73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Stewart G Griffin on May 20, 2008, 02:37:14 pm
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Well, this is the first tankfull that i've run with the digital speedo/odometer.
Initial figures, while not "disasterous," were not too "comforting" either; 15.83 mpg. Mostly highway driving.
The setup:
350 Crate engine---260 horse version, everything stock--all vacuum, emmisions, air cleaner installed. Stock, non-CCC quadrajet. Stock exhaust manifolds.
AC delco R45TS plugs----for now.
TH-350C
2.56 rear diff gear.
Off brand 235/75 15 tires aired to 35psi.
Dual exahaust with dual cats after the stock manifolds. Flowmaster 40 series.
Truck is at stock height---not raised or lowered.
Weight unknown, but probably between 3800 and 4200
The engine turns 1800 at 55 and 2100 at 65.
As far i know, and to the best of my ability, the engine is set at 8 degrees BTDC initial. Also, the non-esc dist, we think, is out of a 76 chevelle station wagon, but this is really unknown as well.
At first, since this is not my daily driver, i was going to pretty much leave everything as is and not really worry about it; .24 cents per mile fuel cost for something i can use to go to home depot, move furniture and large stuff around is not too bad---if this was a stable price. But since, lately, gas seems to be rising at .10cents per week, this is unstable. So we'll see. i may very well have to go to high-compression heads and water injection.
For now, the short-term items i'm proposing are:
1) Since i need an oil change badly, i'm probably going to go with synthetic. What weight oil should stock SBCs run?
2) Aerodynamics. i think this could really help. Tonneau cover, the open grill area can be made smaller.
The underside.
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Didn't we already talk about all this stuff?
Advance your timing and make sure the distributor advance and vacuum advance are working correctly, forget the synthetic, Adding the tonneau cover is going to add weight, and your high compression heads aren't going to help either. Change your final drive ratio and plop a 700R4 in there. Those are your best most cost effective mods.
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do a cost analysis, too. if you only drive a couple of thousand miles a year in it, it will take a long time to recoup the cost.
planned savings at $4/gallon:
1mpg increase at 1000 mi/year = savings of 1000/4 = $250/year
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Your almost 16 mpg will likely be 11-12 around town going to Home Depot. I'd say your probably close to ideal with what I would expect. That is about what my 454 does but I put less that 1500 miles on it a year.
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I have found that a bed cover will give you about 1 mpg improvement on average. As mentioned with your minimal driving it would take several years to recoup your cost. But then again gas is on the rise once more....:(
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my '84 with the holley when I first got it set up right was getting about 15-17 w/ a 305/th350c/2.73 out on the highway at 65 mph..when that trans died, a non-lockup th350 was installed and mileage dropped to 14-16, I started using the soft tonneu cover again (very lightweight), and my mileage went down to 12-14 average, took the tonneu cover back off, mileage went back up. Dropped the tailgate, mileage went down to 11-14. Took the tailgate off, 13-15 mpg. Best mpg was no cover, tailgate up, windows up, AC on, cruise on. Gave it to my dad, before it ate a cam lobe, he was getting 10-12 with all the junk in the bed. These aren't one tank readings, thats the mileage i got making regular 120 mile trips.
+1 on the cost analysis..if you only drive 1000-4000 miles/year, it will take awhile to recover what you spend to improve the mileage by 1-3 mpg..even at $5/gallon for gas..
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For the second tankful, 16.89. i'm not sure of why the big jump; The only thing different this time was i switched to Mobil 1 synthetic 10-30W oil. And i don't think synthetic would account for a 1 mpg increase? The previous oil was the same oil as when i bought the truck---i have no idea what kind/weight it was and how long it was in there.
But i do everything the same; i put the nozzle all the way in and let it click it off---i don't top it off.
It was 305.7 miles and 18.09 gallons to fill up. $74.69 ouch. i will get my previous figures when i get a chance.
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$74.69 ouch. ha ha ha ha try $143.40 over here!!
I guess cost comparisons are always relevany tho
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Move closer to Home Depot.
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Move closer to Home Depot.
:D nice..
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Let us please not joke around at a time where gas is over $4 per gallon.
Thank you.
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It doesn't hurt to keep a sense of humor about it since there's no point in getting upset. It's just the way things are, get used to it. You could always sell your truck and hire contractors to do everything around the house. But that would cost alot more than keeping fuel in your parts/supplies go-getter, depending on how much work you've got to do. And if its your play thing or hobby truck, suck it up, fun/hobbies cost money (lots of it), always have.
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Hey, just find yourself an 82 Special Economy C10 and you're all set:
http://www.73-87.com/7387info/ads_GM/82_20mpg.jpg
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LOL, that's back when they tested fuel economy downhill, gearbox in neutral, in the slip-stream of a semi-truck, with a 30mph tailwind.
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i don't doubt that the truck could make 20mpg, but 28 is a bit of a stretch.
i was reading more about that engine---it was a special 305 with 9:5ish compression, special heads, special Q-jet. i'll try to locate a link shortly.
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Ok, for the third "cup" it is 17.20. i really can't explain the continual rise upwards except that when i switched oil, i was already, say, 1/4 into the second tankful. So, therefore that might explain the rise from 3rd tank from 2nd tank. But switching to synthetic wouldn't account for a 1 and a 1/2 mpg increase? Or would it? i also forgot to mention that during the oil change, i also added "Prolong" engine treatment. Now, there probably is a big controversy regarding engine additives and, honestly, i really don't know. But i do know that one of the proponents of "Prolong" was Smokey Yunick and he was not a B.S.er, nor was he a sellout. And that is the only reason why i use it.
302.6 miles, 17.59 gallons to fill up. $71.41 lasted about 5 days.
The only reason why i'm driving the truck everyday is because the cavalier, my daily driver, needs new brake pads and i ordered ceramics and they haven't come in yet; The use of ceramics vs. semi-metallic, looking back on it, was probably unnessesary as the semi-metallics lasted 3.5 yrs. But my philosophy is when you don't have monthly payments, you can afford to buy the best parts.
2) Here is a link to the economy special engine:
i've cut + pasted the info regarding the LE9 305 engine. It is from wikipedia, so it's ok to cut and paste. And, yes i am aware of the accuracy problems with wikipedia, but i think in this case the info is pretty accurate:
LE9
Years: 1981-1986
The LE9 305 was the truck/van version of the High Output 305. It also had flattop pistons for a 9.5:1 compression ratio, the "929" truck 350 camshaft for more torque, 14022601 casting heads featuring 1.84/1.50" valves and 53 cc chambers, a specially calibrated 4bbl Q-Jet, the weird hybrid centrifugal/vacuum advance distributor with ESC knock sensor setup, and lower restriction exhaust. The engine made 210 hp (157 kW) @ 4,600 and 250 lb·ft (339 N·m) @ 2,000 rpm.
Or you can scoll down to the LE9 section under the 305 section:
http://en.wikipedia.org/wiki/Chevrolet_Small-Block_engine
3) i'm thinking maybe i should have held out longer for a TBI truck or better yet a 4.3 tbi truck.
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A truck high-output 305? Wow, never heard of it. And that was what they put in the "special economy" package? Doesn't make a whole lot of sense they would market it that way, since it made around 60 or more horse than the regular 305 in the trucks. I'm trying to think in what application they would have sold that in the trucks. That made more power than the 350 too, if it indeed was 210 hp. A special economy 305 I believe, but one that makes more power than the rest I do not, when considering factory-built engines in the early 80s.
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1) yes, this was, apparently, the "truck" hi-output version of the 305; The monte carlo ss had the car version----L69. Both were very good engines; i'd like to duplicate either one. i think chevy marketed the engines along with the base engines due to cost----the special ones were higher priced; The monte carlo ss's engine made more power AND got better mpg then the other monte carlos with 305. So why would anyone want a base LG4 305? Go figure?
2) For the forth "serving," the "honeymoon" is (possibly) over. 16.11 290 miles even and 18.0 gallons even. $71.82. i seem to be getting 5 days usage out of a tank. The only explaination i have for the mpg drop is that i got caught in a bad traffic jam this time. i couldn't shut the engine off because it was the kind where you creep up every few seconds etc. This was for probably a 1/2 hour. Also, there was a little more "city" driving this time.
3)Did any of the 73-87 have CCC and if so, it would be interesting to know what kind of mpg these trucks get?
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LE9 was NOT the economy version of the 305.
The economy version was the LG9. It was a 2bbl 8.5:1 305 without the ESC. It made 130hp and 240lb/ft and was only available in 1981.
Wikipedia is about as accurate as the person inputting the information, and that info is fairly broad and inaccurate. In 1981 the LE9 only made 160hp and was the same in 1986 when it was replaced., it never saw 210hp. It also was only 9.2:1, not 9.5:1. LE9 was the base motor for all 81-86 trucks and it was the ONLY engine for 1/2T 2WD pickups from 81-86.
1986 I am pretty sure was the only year CCC was used...
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Upon further research----checking the brochures, it turns out that the LE9 engine generally "only" made 160hp and 235 tq at 2000rpms, but in the 1/2 tons it made 185hp and 240torque at 2000rpms which is still pretty good.
It's unfortunate about wikipedia; i guess the moral of the story is we really can't trust wikipedia all the time at this point. I thought the 210hp was a bit of a stretch; Maybe they got it confused with the big-block which was rated at 210 for these model years.
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Wikipedia is good for nothing. Don't believe everything you read unless I wrote it ;D
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And I proof read it... ;)
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LOL You guys sound like my brother when he posts stuff about car audio. Few, if any, can challenge him though.
Heyyyyyyy, I'm pretty sure than my 81 Jimmy 2wd had that LG9 motor. It was an 81, did not have ESC, had a 2bbl 305 and........it was gutless lol And I sure don't remember it ever getting anything good for gas mileage. But hey, I was 17 and gas was 50 cents a litre (unlike $1.50 now). I wouldn't have noticed if it got good mileage anyway lol
I remember when I bought it in 1992 it did 0-60 in 14 sec. I had a tune-up done, put on a 10" open-element air cleaner and shaved 3 SECONDS off. Too funny.
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Gads I love this post.. LOL :D what happened to Sgt Del?
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what happened to Sgt Del?
As Buckweat would say,......"Here I is!"
Stewart wants us to get serious, so I had to bail. Serious is no fun. In actuality, when I said....
Move closer to Home Depot.
I was being half way serious. Moving closer to a Home Depot is not a bad idea, point being, if you live out in the sticks, you gotta pay for it.
When it comes to MPG, I really have no input. My sub gets around 12 on good days, and my 383 stroker, well, she won't top that ('cause I like to keep my foot in it and pass a Ford each time I see one ;D those duals sound so niiiishe). But, I live within 4 miles of three Lowe's, two Home Depots, three McDonald's, two libraries, and 3 WalMarts (no kidding). Except when I am pulling my home on wheels on vacation (my 30' camper trailer), I don't use much gas because of my location. In fact, wife, son and I went out to dinner tonight---had to travel a whole 1/2 mile to get to the restaraunt--which is right next to the Richmond Amtrak Station. Son likes watching the trains go by. (we drove the Taurus [29mpg] to save gas.)
MPG? who cares? What is, is, and what ain't ain't. How's that for the thought of the day? Nuttin' much we can do about the trucks we drive. Besides, we don't have $700/month truck payments! For some reason, an 80's era song comes to mind....ooohh,ooooh,ooooh, Don't worry, be happy....ooooh,ooohoooooh.
Now I need to calculate which month I need to fill up my sub tank....maybe late August I'll drop another $130 on it--gotta start saving now--darn, why did we go out tonight when I could've fixed hotdogs for everyone for less than $2 and shown my son pics of trains?
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3 Wal-Marts?! I would move! lol
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With 3 Walmarts he can probably barely get outta the neighbourhood with all the traffic.
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I gotta say, it's convenient. Not too much traffic, i live off the main highways so my street is kind of quiet. It's rare to have a traffic jam 'round here---except on I 95 when accidents occur. Three miles west is a pretty busy place w/ all the big stores. 4 miles north, same thing. Two miles east is a pretty big shopping complex. I am kind of centrally located. Oh, I am 1.5 miles from work.
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Wal-Mart, you'll never find a more
(http://www.littlechocolatedonuts.com/images/shirt-wretched.gif)
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Tell us what you really think ;D
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I'm guessing you don't get C-SPAN?
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For the 5th "serving" we have 15.86; 276 miles even, 17.399 gallons, $70.27
i don't have any explaination for the declining figures. Perhaps the temperature rising?
i think some carb and ignition tuning could really help things out but i don't have time to learn right now.
i'm not too disapointed though; i have a decent running, dependable, rust-free truck which i got for $1500. i could go buy a new Silverado for 29K and get 20 mpg, but it would take alot of driving just to break even (nevermind "saving") for the 27K spent to get 5mpg more.
2) about the home depot thing---i live about 4 miles away from the nearest which is close enough for me. Pls see above rationale.
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Wal-Mart, you'll never find a more
(http://www.littlechocolatedonuts.com/images/shirt-wretched.gif)
Classic! ;D
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I've had 1/4 tank of fuel in my truck for at least 6months. Uses very little, infact I probably have more evapourate than I use ;)
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just filled up my tank on the 383 stroker 79 big 10. First time since early May. 17.6 gals for $70.50. Did i ever mention i love driving that truck? I have to fix a few cancerous spots on it though.
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Just for interesting's sake, the cavalier got 32.45; 400 miles even, 12.325 gallons, $49.16
This is with the 2.2 4cyl which is, i believe 134? CID
3 spd auto, i believe the axle ratio is 3.18 or something; The rpm at 65 is 2600ish.
Everything is stock.
This is a pre-air bag model and thus the weight is 2300lbs and some change.
Interestingly enough, i'm using royal purple synthetic 20W-50. Why so thick? Because i think i might have had a problem with low oil pressure, but that has since "vanished."
Future plans include swaping in a 305 SBC while staying/keeping FWD when and if the current engine stops running. And yes, i have done some measuring and i think it will (just barely) fit.
i guess one of the points here is that you don't have to go with hondayota and co. if you want better mileage; All j-bodys, despite what anyone says, are very dependable and fairly easy/cheap to maintain and are very durable.
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I've had 1/4 tank of fuel in my truck for at least 6months. Uses very little, infact I probably have more evapourate than I use ;)
I took my bed off about this time last year and painted everything with chassis saver, including the tanks. Each tank was half full. This was in the 100+ degree spell we had July thru early Sept, and by the time I was ready to crank it all the gas had evaporated.
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We dont see 100+. Lucky to get 70!!
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i guess one of the points here is that you don't have to go with hondayota and co. if you want better mileage; All j-bodys, despite what anyone says, are very dependable and fairly easy/cheap to maintain and are very durable.
I mentioned somewhere here that my wife had a '96 Saturn with a 2.0 4cyl and 5 spd manual that routinely got 39 mpg on the highway on 87 octane. We traded that in for the peppier 2.2 4-banger with DOHC, 5 spd, air conditioning, and power steering (yes, the first Saturn was a $#@% to park with no P/S, and hotter than heck with no A/C) and that managed a cool 36 mpg.
And all these hybrids that get "an amazing 36 mpg highway" - Please, just go get yerself a $12,000 4cyl with a stick and you can get the same mileage driving it like you stole it versus driving it like your grandma "to optimize fuel economy".
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Right; What i'm perplexed about is the new aveo (i think gm's smallest car) is rated at 34, meanwhile i just knocked down 32 with a 1990 cavalier. Another perplexing thing is that the cobalt, which is larger than the aveo, is actually rated higher--36 vs. 34 than the smaller aveo?
So newer, as usual and with mpg, does not nessesarily mean better.i wonder why the current subcompacts are heavier than previous subcompacts? Again, my cav is 2300ish vs. today's cobalt at 2800lbs?
To their credit, the new malibu is rated at 32. And the malibu is much larger than any cavalier.
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The Aveo gets worse highway fuel economy than the larger Cobalt for the same reason the Honda Fit gets worse highway fuel economy than the larger Honda Civic. The engines are considerably less powerful in the Aveo and Fit and obviously under considerably more load on the highway than the larger engined Cobalt and Civic. This is the same reason that under certain conditions a 350 will get better gas mileage than a 305 (or even a 4.3 V6) as we are discussing in this thread (http://forum.73-87chevytrucks.com/smforum/index.php?topic=8949.0), which has turned into a big sythetic oil vs petroleum oil debate. Also I'm sure you know that the EPA has revised their fuel efficiency test to better reflect the average maniac American driver, so more conservative drivers can actually average better than what the EPA predicts. In other words, if you can get 32 out of a '90 cavalier you will likely get better than 34 out of an Aveo or 36 out of a Cobalt, if you use the same driving style.
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My wife bought her mom's Taurus 4 dr sedan for $1k. Mother in law doesnt drive. Father in law died.
That thing got me 30 mpg with three guys in it with A/C on. And she ain't underpowered. Not bad, huh?
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You were in a Ford!? Shame on you!
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Fords are all my company allows as lease cars. I have had 3 Taurus and 1 Sable which I still have. The deal my company gives on these cars when they are 2 years old with 70-80K on them I can't pass them up. Good cars which have an excellent service plan that we are required to have done. I drive them for 2 years, sell it and give someone a deal selling it for the same money. Never got 30 but a pretty constant 26-27 with ours. I got an 08 Escape I am not fond of but 26-27 with the V-6 is not bad.
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Never got 30 but a pretty constant 26-27 with ours.
Yeah, I was amazed. But this is interstate driving from the river house. I drove for mileage, so I am sure that made a little difference. Without three adults in it, or w/o AC on, I would have gotten even more.
You were in a Ford!? Shame on you!
Guilty as charged. When you get a good deal on a car, gotta go 4 it. I still have my moostangs too. :o
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The Taurus/Sable line up of 2000-2006 where excellent cars. The only issue was a fan motor because of a bad housing that was covered under. Bought my last 2 company cars, drove every mile, for $5K. Not bad for a 2 year old car in this day.
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This might be slightly off topic, but then again maybe not:
The cavalier got 33.01 mpg for the second tank; 408 miles, 12.359 gallons, $48.56
i would like to further point out that this was with Throttle body fuel injection, not port injection. You would think port injection would be more precise, but i'll cheerfully take what i got for now.
Also, the car is approximately 1500 lbs. lighter than the truck. It is also much narrower and has a much smaller frontal area than the truck.
2) i don't like the styling of any taurus/sable although the current ones are getting better. i feel that detroit has forgotten that styling sells cars, not mpg.
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I've just clocked up 61k work miles in 15 months so the engine is nice and loose. I'm getting between 55 & 59 mpg at 70-80mph. 2.2Diesel ;) oh its a Honda Accord!!
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That's pretty good Mate. You sure you are converting those Kilometers and litres correctly? That's pretty good mpg Bitzer.
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deffo mpg and mph Sir :) i get roughly 750 miles to a tank! its amazin how much more economical a vehicle is when you drop the speed even by 5mph. i tried a few months back and done 180 odd miles at 65mph and returned 67mpg. Unfortunately 65mph on our motorways/freeways leaves you in and around the artic's (er semi's? tractor&trailer!) and its not pleasant!!!
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As far as daily grind commuting I try to keep it limited to 65 tops and usually cruise around 60 (55 if traffic is slow and scattered). I actually enjoy it alot more than I did cruising at 70+; fewer tailgaters, less frequently caught in a dense cluster of traffic, less engine hum, less windnoise, less stress 8). I save all the juvenile delinquent stuff for those occasions when I'm all alone on my favorite backroads.
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Continued: OH NO!
11.92 mpg with the "new" 305.
214.4 miles traveled, 17.972 gallons to fill up (click off) = 11.92 mpg $48.51 at chevron
This is big-block mpg with 6 cylinder power; How did i manage that?
i think the choke was not adjusted right(and may still not be) until about 100 miles into this last tankfull.
UPDATED SPECS:
Stock 305 from a 78 malibu with rochester 2GC carb
TH-350C not sure if the converter is locking up, but either way the engine is still running about the same rpms at highway speeds
2.56 rear gear
tires are all mismatched 235/75R 15's from junkyard/pepboys.
i still keep it at or below 65mph and no aerodynamic changes have been made yet.
i will report back later, hopefully with some improved news later.
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Bummer Stewart. My carb needs rebuilt but I did a 250 mile round trip Saturday delivering a garden tractor pulling my 14 ft. steel floor car trailer and averaged 12.1 with my 454 4 speed 3.21 gear doing just under 70 mph 150 of those miles.
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I just filled up both tanks for $105. I get around 13-15MPG regularly. Depends on where I get gas. Shell sucks, bp sucks, quicktrip is good come of the time, texaco seems to have the best gas, the most often, around here anyway. shell and bp price gouge, so unless im near a bp or shell i dont drive around looking for a better gas price.
This reminds me of a trip to the lincoln dealer when I was a kid. I went with my uncle and we looked around at the big lincolns. well a salesman came over and my uncle asked what kind of gas mileage it got since it used premium fuel only, and the salesman turned up his nose, laughed slightly and said, sir if you have to ask that question, you cannot afford this car. and then he walked back inside. ;D
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i forgot to add that i think most of the gas around here including and especially exxon (my favorite) is E10.
While i feel E10/15 M10/15 etc. is a great idea long term, this is not doing any wonders for mpg and very probably hurts it.
There is a website which i'll try to find that is a database of gas stations that sell only 100% gasoline.
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Somebody said forget the Synthetic. I use Amsoil Signature series, and I get 20 MPG from my suburban, TPI, of course. But we switched to the Amsoil in my wifes RAV4, and gained 4MPG.
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I'm sure no one on here is going to like to hear this but if you want better fuel economy get a truck with the 6.2 diesel in it. I have a 1984 K20 with the SM465 and 4.10 gears and it gets about 20-21 in town. Its slower than anything I have ever driven tough.
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i love the 6.2 and i think it's one of the best engines ever produced by GM, but i'm not real familiar with getting them to run and for that matter diesels in general. This is why i've chosen to stick with gas for now.
i do know it will bolt right in place of a smallblock---same mounts and same bellhousing pattern. So, it would be easy to physically get it in there. But as far as the fuel pump and injector system etc. i'm lost.
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I'm sure no one on here is going to like to hear this but if you want better fuel economy get a truck with the 6.2 diesel in it. I have a 1984 K20 with the SM465 and 4.10 gears and it gets about 20-21 in town. Its slower than anything I have ever driven tough.
Very true......Slower than Cold molasses running downhill, but, built for fuel economy.
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I've just clocked up 61k work miles in 15 months so the engine is nice and loose. I'm getting between 55 & 59 mpg at 70-80mph. 2.2Diesel ;) oh its a Honda Accord!!
Just had to send the Honda back :'( It got to 3 years old and work said the contract was up! 135k on the old girl and still getting 55+mpg
Sadled with a Toyota Avensis Estate - its horrible and struggle to get 50mpg. It's done 8500miles in 6weeks!!
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http://pure-gas.org/
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Thanks! Exactly the website i was looking for.
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np. this thread got me thinking about the crap gas nowadays. My lawnmower, Monte SS, and Camry were all recently running crappy; either hesitation, loss of power, and/or loss of mileage. I didn't think about the correlation between the different older vehicles till now. I'm going to start gassing up at a station that sells 100% gas, and hopefully notice a change for the better.
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OK, that's more like it------269.9 miles, 16.588 gallons to fill up = 16.27 mpg.
$45.93 at Exxon. $43.46 after rebate which i'll talk about in another thread.
Choke was better adjusted this time. Still not quite 100% but pretty close.
We can see that minus 45 cubic inches(305 vs. 350) probably won't make much a difference in a heavier vehicle.
Do you think that the quadrajet is remarkably more efficient that a 2G all other factors being equal? Even if it does, i'm not really interested in changing over right now.
(http://i223.photobucket.com/albums/dd31/sencraig/gmc1.jpg)
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Ethanol has to be one of if not the biggest comsumer rip off scams ever devised. I noticed I get worse gas mileage with it. So, in the long run I burn more gas! Plus it ran up the costs of everything else in the grocery store due to shortages of some types of grain because of all the farmers swicthing to corn. Fed prices went up because all off the corn for feed going to make ethanol. Thank you Federal Government for once again making the working people suffer while making your croony buddies flithy rich! :-[
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Ethanol definitely was a stupid invention, worse fuel mileage and ethanol attracts water gas' biggest enemy. I work at a marina and we had a really bad run of fuel from the local marina the problem was it was ethanol fuel and any amount of water will end up in the carb and the motor runs horribly. The marina had to switch fuel companies to a pure gas.
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Well, we've opened up a can of worms haven't we?
i though i would mention this before i forget:
i just read that the E10/15 blends have a lower boiling point than 100% gas which can cause leakages out of the carb when the engine is shut off hot. i'm not sure what is going on here when this phenomenon happens, so please discuss this.
Here's the link---i'm not sure how i ended up there, but i thought i would post it before i forgot about it:
If you could scroll down to the bottom
http://www.pontiactripower.com/blog/
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Alcohol absorbs water. Great. >:(
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Stewart, I don`t know where you are located, Altitude wise, But have you considered changing the Metering rods/jets a step or two down? I can remember doing this on a friends 75 k10 with 350, and our best was 21mpg. Timing was at 4btdc. Magnaflows, stock manifolds.
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i'm on the east coast; Not high---i'm ASSuming 200ft above sea level.
But yes, moving down one(or two) jet sizes is a good idea. i may consider that.
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Also consider getting a carb riser.
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Stew- whats up with your picture?
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Stew- whats up with your picture?
Looks fine to me...just a custom job.
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What kind of mileage would be expected with a 4.3 700r4 3.08 combo?
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Well, we've opened up a can of worms haven't we?
i though i would mention this before i forget:
i just read that the E10/15 blends have a lower boiling point than 100% gas which can cause leakages out of the carb when the engine is shut off hot. i'm not sure what is going on here when this phenomenon happens, so please discuss this.
Here's the link---i'm not sure how i ended up there, but i thought i would post it before i forgot about it:
If you could scroll down to the bottom
http://www.pontiactripower.com/blog/
Fuel leaking when the engine shuts off because of the fuel blend? No
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Stew- whats up with your picture?
1) It's just something i was fooling around with as far as a hotrod idea; i'm not real good at drawing or with creativity. i have better napkin drawings which i may reveal later.
2) As far as the 4.3/700r combo, this intrigues me as well; i'm thinking maybe 18mpg IF 2WD and shortbed. Did you see the article at Jeff Drew's site? The article claims 21.9 mpg with 4X4 which i do not believe but hey, maybe it is possible.
p.s. the vortec concept was actually started on cavalier engines.
(http://i223.photobucket.com/albums/dd31/sencraig/gmcattempt2.jpg)
(http://i223.photobucket.com/albums/dd31/sencraig/d57a5b57.jpg)
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the truck is 2wd swb i was thinking around 20
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If it IS possible, then great. The question to me is will losing 40 more cubic inches from 305 and 80 inches from 350 really make much a difference when there is not that much weight loss? (although the article claims 200lbs lighter!)
The v-6 concept does intrigue me deeply though.
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i agree the v6 will have to work harder than a v8 to keep the truck at speed but i am very curious as i am looking into buying this truck and using it as a dd
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Ok, after looking at the brochures, the 4.3 v-6 has 9.3 to 1 compression. That plus the vortec heads maybe 20mpg is possible after all.
i like the v-6 even more now.
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OK I know I have only driven my V-6 a couple of hundred miles but the gas mileage was terrible, 10 at best... Truck ran well but I had to keep a heavy foot to keep it going down the highway at 65. I would play with the jets until you got the exhaust pipe a light grey and the spark plugs burning right. I did that with a 2 bbl on a 350 on my 1972. It had an ever slight hesitation starting out but I managed to squeeze 16 mpg out of it.
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256 miles even, 16.9 gallons to fillup = 15.14 mpg This is at Exxon and it's confirmed--- "contains ethanol" on the pump.
Not quite sure what is happening here; The choke is still not right, still too rich and the carb itself may need some tuning. This is a remanufactured carb from Champion, and i can't say i'm too pleased with it right now. If you need something to get your car running ok, but other than that i don't know.
2) If you're still interested about 4.3 v-6 mpg, there is a former gm engineer getting 20mpg with a shortbed in the 67-72 forum; Will post link if i get around to it.
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it normally costs me about 80 bucks to fill up but i can get around 840 out of a tank of fuel
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I took my Aluminum intake off and replaced it with the factory one. I replaced the headers with the factory cast iron manifolds. I put my stock factory heads back on and went from 2 1/4" duals with headers to 2" duals with manifolds. Mileage went from 12MPG down to 10.7. Still have the flat top pistons and around 9.5 compression. Would love to see anything anywhere close to 15.14. But hey, it's a 3/4 ton. So I don't expect much anyway. :-\
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I took my Aluminum intake off and replaced it with the factory one. I replaced the headers with the factory cast iron manifolds. I put my stock factory heads back on and went from 2 1/4" duals with headers to 2" duals with manifolds. Mileage went from 12MPG down to 10.7. Still have the flat top pistons and around 9.5 compression. Would love to see anything anywhere close to 15.14. But hey, it's a 3/4 ton. So I don't expect much anyway. :-\
Why did you do all that? In an attempt for better mpg?
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267.6 miles, 16.00 gallons = 16.725 mpg.
$41.27 to fillup @ $2.579 per gallon Exxon
i don't drive it very much hence the slow responses.
More choke adjustment----almost there. And both idle mixture screws were adjusted using a vacuum gauge; Trying to get as lean as possible while keeping max vacuum---about 21-22 hg's.
i continue to try to only make one change at a time, so i/we can accurately see what works and what doesn't.
But for anyone who hates 305's, this is what a 305 can do. And i think i can get more out of it.
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259.4 miles 16.105 gallons to fill
16.1 mpg
$44.43 @ $2.759 per gallon, exxon.
$42.02 after rebate.
Looks like this is a 16mpg truck and i have to accept that.
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I took my Aluminum intake off and replaced it with the factory one. I replaced the headers with the factory cast iron manifolds. I put my stock factory heads back on and went from 2 1/4" duals with headers to 2" duals with manifolds. Mileage went from 12MPG down to 10.7. Still have the flat top pistons and around 9.5 compression. Would love to see anything anywhere close to 15.14. But hey, it's a 3/4 ton. So I don't expect much anyway. :-\
Why did you do all that? In an attempt for better mpg?
No, I just got tried of that stuff. It started when my truck ran hot and I cracked one of my 882 heads. A 3/4 long bed is no way ever going to be a hot rod and still have any reliability if I build it. While I had it down, I just decided to put the factory stuff back on. I feels like it has more torque now but you tell the difference in HP around 60 to 70 MHP. Correction: I meant 2" duals with glasspacks, not manifolds. I just noticed that.
I do have an update: I replaced the factory air intake with the big hose to an open element air cleaner I had and my mileage is back up to almost 12 again. Like 11.7 MPG. That's with a K&N filter. It rides a little better with the extra weight of the cast iron back on the front.
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I took my Aluminum intake off and replaced it with the factory one. I replaced the headers with the factory cast iron manifolds. I put my stock factory heads back on and went from 2 1/4" duals with headers to 2" duals with manifolds. Mileage went from 12MPG down to 10.7. Still have the flat top pistons and around 9.5 compression. Would love to see anything anywhere close to 15.14. But hey, it's a 3/4 ton. So I don't expect much anyway. :-\
which intake,,heads and headers do you have ??
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278.3 miles, 16.72 gallons = 16.6 mpg
$2.799 per gallon @ exxon = $46.80
$44.30 after rebate.
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$46.80 per gallon
kind of expensive ;D
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$2.799 per gallon ;D
i work odd hours, hence the flub.
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261.9 miles, 17.153 gallons = 15.27mpg
$64.48 to fill up. Sign price was $3.75 for regular. After i got my .15 per gal discount because i have the exxon credit card, it was $61.90
i am going to get serious about aerodynamics. Stay tuned.
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You know the slower you drive the less influence aerodynamics have. Have you tried out the "driver mod" yet? Are you practicing some "hypermiling" techniques?
http://www.cleanmpg.com/cmps_index.php?page=hypermiling
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Um.. not really into hypermiling; Really my whole goal with mpg is to be able to drive without worrying about mpg. In other words, for example, i never worry and have never worried about mpg when i'm driving my cavalier even though it still takes gas and money to operate one of these or any honda or similar mpg vehicle. But it gets 28-32 mpg so i don't worry about it even though this still does cost money, but not enough money to point where i'm worrying about it.
Regarding speed, right now i don't go faster than 65 mostly for mpg reasons but also because it's easier on the engines. i want to be able to cruise at 70-75 and again not have to worry.
i think 20 mpg, which i feel is actually a realistic number for these trucks, would get me to not worry anymore. 24 is a stretch but technically possible. Actually psychologically, which is what it's really about for me, diesel would be the best/easiest solution, but at $8000 entry fee it does not pencil out for me---it would take 100,000 miles just to break even before seeing any savings. This is not taking into account if we put the 8K into a conservative CD at 3-5% instead of buying the diesel engine, it will take maybe 150,000 miles to catch up or we may never catch up...
i will probably start a thread concerning mathematical calculations concerning this very topic. Gas vs. diesel vs. 6 cyl etc.
P.S. The short term thing i'm going to do is advance the timing a little before getting into aero. i don't know exactly how much i'm going to advance it because i can't find the timing tab.
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Really my whole goal with mpg is to be able to drive without worrying about mpg.
Like any relationship, if you can't control the parameters, you can usually at least control your mind. Yes there are things that can be done to improve mpg's with these pigs, but they will still be a pig when you are finished. In the time they were made, with the technology that was available, and the speed limits that were enforced, these trucks did just fine. Compared to new technology vehicles and their fuel economy, current gas prices, expansion of cities and the city traffic, and higher speed limits on interstate highways, a vehicle with the ballistic coefficient of a box of potato chips will never compete with what is now considered the 'norm'. All that's left is to wrap your mind around the fact that these trucks are cheap on parts and easy on labor, so go ahead and drive without worrying about mpg, because you will still most likely be saving money in the long run compared to buying a new vehicle or swapping everything under the hood to try to gain .08976 mpg.
If you're running a 305 it should be up at the 12 o'clock position. You can always advance it til it pings and back it off til it's right.
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Are you practicing some "hypermiling" techniques?
I just drive slower and try not hyperventalate when I pay for the gas. :-\
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Regarding aerodynamic mods, here are some ideas.
I would first start off with extending the front bumper down to almost the ground and installing a cover that angles downward from the cab down to the tail gate. You can use thick rubber to bring that bumper down. There are a bunch of other things you can do such as using pizza pans as hub caps or rear fender skirts but then the truck starts to look silly. Also, make sure you are using low resistant tall and skinny tires. If your truck is 1/2 ton, go with a 30x9.50 and if it's 3/4 ton, go with a 215/85/16.
Here are several truck that were ecomodded to the extreme to give you an idea what I was explaining. Pay particular attention to the slopping canopy and the front bumper. These guys also smooth out the bottom of their trucks with a pan so they don't need to extend the bumper so far down.
--And oh by the way, that 1994 Toyota T-100 went from 23.3 mpg to 32 mpg at 75 mph. And that truck was a lot more aerodynamic than our trucks so there's even more gain to be had on our square bodied trucks.
(http://www.blogcdn.com/green.autoblog.com/media/2010/01/toyota-truck-ecomod.jpg)
(http://ecomodder.com/imgs/knox/knox-1962-dodge-z.jpg)
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I'm sure no one on here is going to like to hear this but if you want better fuel economy get a truck with the 6.2 diesel in it. I have a 1984 K20 with the SM465 and 4.10 gears and it gets about 20-21 in town. Its slower than anything I have ever driven tough.
Very true......Slower than Cold molasses running downhill, but, built for fuel economy.
Yup, they are very slow in stock form but can be woken up quite easily which usually ends up gaining some additional fuel economy. The 6.2 diesel in my 1982 came with 135 hp from the factory and it was dangerously slow. However, the engine would return mid 20's on the highway. I later went in and installed headers and large free flowing pipes. I also matched and ported the heads and turned up the fuel injection pump. The thing now is fun to drive and has plenty of power. I'm also able to tow my 26' Airstream travel trailer weighing approximately 5000 lbs. with ease. And better yet, the fuel economy increased from the mid 20's before the mods to 30 mpg on the freeway driving between 55 and 60 mph. The truck has a 3.08 rear end and a 700R4 transmission.
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Um.. not really into hypermiling; Really my whole goal with mpg is to be able to drive without worrying about mpg.
Regarding speed, right now i don't go faster than 65 mostly for mpg reasons but also because it's easier on the engines. i want to be able to cruise at 70-75 and again not have to worry.
i think 20 mpg, which i feel is actually a realistic number for these trucks, would get me to not worry anymore.
Well you are saying you are ready to perform extensive body mods for improved aerodynamics, but are unwilling to make slight adjustments to your driving style. ???
It's not a "worry." It's easy. The single most important thing you can do is slow down on the highway. I have found that not getting caught up in the stupid little daily rat race makes driving a little nicer too - just slow down, hang out in the right lane, turn on the tunes, and cruise. As long as there isn't a big difference in speed between you and majority of traffic, it's safer too. I feel that 5 mph slower than the flow of traffic is hunky dory (just stay out of the left lane), but 10 mph slower could be dangerous in anything more than very light traffic.
I think that's a realistic number too. And I don't think any aero mods would be necessary to achieve it.
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256.6 miles, 16.712 gallons = 15.35 mpg
$59.81 to fillup, after rebate = $57.31
$3.579 per gallon regular.
Advancing the timing did not seem to have any effect.
The situation will be dealt with.
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256.6 miles, 16.712 gallons = 15.35 mpg
$59.81 to fillup, after rebate = $57.31
$3.579 per gallon regular.
Advancing the timing did not seem to have any effect.
The situation will be dealt with.
At what speed was you driving? If you were driving 65-70, that would not be too bad. However at 55 mph, you should get somewhat better than that considering you've got a 2.73 rear end and a transmission with a lock up torque converter. Have you looked into having the carb jets sized/tuned?
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At what speed was you driving? If you were driving 65-70, that would not be too bad. However at 55 mph, you should get somewhat better than that considering you've got a 2.73 rear end and a transmission with a lock up torque converter. Have you looked into having the carb jets sized/tuned?
i keep it at or below 65, it's got 2.56 rear, haven't gotten around to jet resizing yet.
255.1 miles, 16.167 gallons = 15.77 mpg
$56.89 to fillup at $3.519 per gallon
i also did some towing last week and here are the specs:
270.3 miles 17.452 gallons = 15.488 mpg partially with empty trailer about 100 miles were regular unloaded, no trailer miles, and the other 170 were with unloaded trailer.
203.7 miles 14.646 gallons = 13.90 mpg 153 miles were loaded with car.
198.1 miles 14.975 gallons = 13.22 mpg all miles were loaded with car.
P.S. the other frightening thing as you look thru the thread is that gas has risen $1 since september!
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yea,, that sucks so bad. a whole dollar is insane. sadly, we more less have to accept it
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tonneau cover installed. Will report back asap.
Grill dam is being worked on as we speak.
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294.5 miles, 16.772 gallons = 17.56 mpg :) This is the best mileage since i started keeping track.
i did not install the tonneau until about 140 miles into this tank.
i like these numbers, but let's say for now results are inconclusive----should run a few more tanks to verify.
$3.59 per gallon. $60.36 to fill. Price has risen .15 in one week.
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297.8 miles, 17.007 gallons = 17.51 mpg. i had more stop+go driving this time.
i think i would like to confirm it; Tonneau cover works! i'd like to say 1.5 mpg improvement but would have to recalculate to be accurate; i thought/think that i was averaging around 16mpg all along and with the addition of the tonneau it's 17.5 although with just two tanks this might not be accurate to call it now.
Unfortunately the aerodynamic testing and experiments are going to have to be put on hold indefinitely due to large amounts of fertilizer being spread at work.
So no more testing, but i will continue to report mpg.
Exxon regular at $3.659 per gallon. $62.23 to fillup.
Updated specs:
78 LG3 305 engine completely stock. This means 8.2 ish compression?
Rochester 2GC carb
Not sure where timing is because i can't find the timing tab and i'm not going to make any effort either.
Stock exhaust manifolds but with true dual exhaust but no crossover pipe. Flowmaster 40s after dual flowmaster cats.
TH-350C trans
2.56 rear diff gear
Truck is at stock height. Weight is probably 3800 or more.
One new pepboys "cornell" 235/75R 15
two other salvage yard$10-$20 specials Yokohama/general 235/75R 15 probably came off a toyota or mitsubishi suv/truck
One salvage yard $10 special BF goodrich 205/70R 15 Note: this smaller mismatched size is mounted on the front.
i plan on switching to new michelin harmonys or X soon.
1/2 ton longbed; Maybe longbeds benefit more from tonneau covers than shortbeds?
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Last month totals:
1) $389.59 food
2) $112. 59 gas.
Just to put it in prospective.
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Those numbers are really good, I went on a trip with my girlfriends father to PA a few weeks back we were getting something less than 19 mpg the whole way, almost all thruway. His truck is a 2008 Silverado 1/2 ton 2wd 4.3 V6 No CC. we had the air on windows up and nothing in the bed. all the times we checked mpg it was around 18.6, now he drove it a little harder than I would have if I was going to try for good mpg but it was thruway miles and not too hard of the gas pedal. So realistically your truck is getting only slightly less mpg than an almost brand new truck.
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250.4 miles, 16.155 gallons = 15.49 mpg
i took the toneau cover off because i was helping someone move and then i could not decide (and still cannot decide) if i want to build a shed in by parents' backyard. i will probably put the cover on soon.
The only other change is i got a new tire.
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well i only get 16 with a 2007 GMC Sierra Z71 with the 5.3 but i got a big right foot
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257.9 miles, 17.506 gallons = 14.73mpg
$3.3319 per gallon regular at mobil $58.10 total to fill up.
i think/hope part of the problem was that i was using the very tiny mr. gasket type air cleaner---the 3 1/2" diameter and i think it got clogged. The reason why i ran this filter since i think summer 09 was to get the carb worked out---it's easier this way but then i forgot about it----because it seemed to work well. i have now switched back to the stock 14" filter.
The other thing was that i still left the tonneau off. i really think aerodynamic modifications really work.
Also, there was a stretch of about 20 miles where i really had to hammer it because i was late for an appointment. Like going 75+, which i normally keep it 65 and below. 305's run better than you might think.
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275.7 miles, 17.446 gallons = 15.80mpg
$3.199 per gallon, $55.81 total to fill up,
i'm not sure what is happening here. Maybe it is the "winter blend" gas?
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(http://ecomodder.com/forum/attachment.php?attachmentid=1213&d=1216790008)
You could try a partial (rear mount, leave the front part of the bed open) cover, with a flap/spoiler mounted to the cab roof
angled down a few degrees. According to quite a few studies, it almost shows the drag reduction of a full aero cap, without
destroying access to the bed. I figure I'll try that on Earl in the not so distant future.
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YES! i like the partial tonneau idea---it seems counterintuitive, just like leaving the tail gate up as opposed to down, but research indicates that both are better for mpg.
i was doing some more thinking and i've realized that maybe most of my driving is not strictly highway cruising; It is mostly on the highway (2 lanes in each direction w/ median strip, 55 speed limit), but there are quite a few traffic lights. And when you have that, you don't have steady state cruising. It's more like a combined city/highway mix.
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For that, I'd be tempted to find a relatively simple, non-obtrusive "hybrid" setup, maybe a plug in electric "booster" motor tied in to the drivetrain or a wheel to take up some of the acceleration load, maybe even with some regen on braking. Also, the hydraulic hybrid that UPS is using on some of their trucks appears to be making some really impressive numbers as well.
I know some folks aren't gonna like the idea, but I think someone with enough ingenuity and the ability to scrounge can probably have a setup that pays for itself pretty quickly.
If it's mostly highway miles, the aero mods are probably the big ticket.
I've even considered a 4bt swap in Earl, but I'm a long way from doing anything major at this point.
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I have been driving my cummins 4bta suburban for about a week now. I did the math and it will take me 70000 miles to recoup the money I have in the swap at todays fuel prices, but that includes a new tranny as well. I don't have definite numbers on the mileage yet, but I am guessing 20mpg with mixed city and highway, but I would not call it slow. I will post numbers when I have them. It is not fast by any means, but it will pass and move in and out of traffic fine. A 6.2 could be done a lot cheaper I just didn't want that engine for lots of reasons.
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I have also been reading that with a lighter vehicle like a 2 door truck that this engine will get mixed 25mpg or higher. If I could do all over again. I would in a heartbeat. Next time might be a Jeep.
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I've heard rumors of 30+ mpg with that setup on a 1/2 ton 2wd truck, but I'd have to see it. If that were the case, however, my pickup would be right up there with my little HHR, and close to my wife's Cruze. Since I tend to want to keep vehicles a long long time, it'd eventually pay for itself. I wouldn't be averse to a 6.2 swap if I felt it would hold up for the long haul (ha! pun!), and I'm not hard on trucks at all.
Then again, if I could figure out how to beat 20 with my 350, I'd just keep it... but by the time I got to that point, I might have spent what a reasonable diesel conversion would cost. I also considered a 4.2 Atlas swap, but again... for the cost/effort, an oil burner might be more economical in the long run anyway.
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I don't have exact numbers yet, but I went about 600 miles on a 31 gallon tank with mainly city driving. I wrote down what was on the odometer and will report when I fill up again. Just let ya know I have 6000 into this swap with a new tranmission, having everything rebuilt, and a few hundred dollars worth of road blocks. I did all the labor myself. I have had this truck up to 85. Acceleration could be better, but it's pretty much all stock.
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Wal-Mart, you'll never find a more
(http://www.littlechocolatedonuts.com/images/shirt-wretched.gif)
If I owned land as you entered DC, I'd have that made into an official looking sign and have it planted out by the road.
But Stewart, your MPG problem is exactly why I'm going with a 5.3L LS engine swap instead. I know that doesn't help now, and may have been well outside your budget, but I think mileage is one of the main reasons people choose it these days (if they can) as opposed to one of those older boat anchors like we have. The LS just beats the crap out of all those old motors, I'm afraid.
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i agree and what i would really like to look into is an LS with cylinder deactivation. You know maybe get one out of wrecked impala or gxp. You can have power AND economy.
But the hangup is how long will it actually take to install one and get it running? i've seen threads on these swaps. They tend to drag on and on...... They don't look plug and play.
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If you get everything ready before pulling the old one out, is shouldn't take too long.
I am about to yank the 305/700R4 out of my R10 and plan to document all that is required.
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So you're going to do an LS swap capt? That will be interesting to see. Are you doing a 5.3? When I finally do my 5.3 someday, I'm going to get the newest one I possibly can, regardless of the challenges that may present. Hopefully just a year old. The benefits to getting one that is next to new with very low mileage far outweigh any obstacles to overcome imo. Cause I know some people will say you should get a certain year or else you're going to have to do this and this and this...but I want the new stuff like stewart was talking about like cylinder deactivation.
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269.2 miles 16.756 gallons = 16.07 mpg.
$52.26 to fillup. @ i guess one good thing is that it's $3.11 per gallon regular at mobil. After my discount i think i will pay $49.75 total.
i will continue to report mpgs although i don't think it will change much because i haven't made any changes and don't plan to for a while because other stuff came up. i have to go back on what i stated earlier-----i now can't confirm that the tonneau cover actually helps in my particular case.
2) As far as the cyl deactivation go for it! i'm not sure if the current silverados have this. i also think you could get a brand new LS crate AND cylinder deactivation but i am not sure.
3) i want to eventually start a new thread dealing with a new topic of saving money on gas (as opposed to getting better mpg), but i don't feel i can actively contribute to it. So, until then just a heads up exxon/mobil is offering a free $10 gas card if you buy a $100 gift card----So basically $100 of gas for $90. i think they are allowing 2 per "household" whatever that means, so you can get $200 of gas for $180.
If you purchase these cards with a credit card that offers rewards points etc., then the cost can be even less. For example, i have the fidelity american express that offers 2% off everything----so this means $200 of gas for $176. (further $4 discount)
You have to purchase the cards by dec 31st though. And i think you can only get them at the actual stations---can't buy them online?
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There is a small bag of tricks that you can use to get better MPG. They all sound small, but they do eventually add up. I've always wanted to see what kind of MPG a motor made that had ALL of them done. Even if its just a little bit, these days it seems like it might be worth it. Again, some of these, you may not even see an increase at all. But once they all add up, and they all start to work together, you might get a little bump in MPG.
1. Full synthetic drivetrain. In my stang, I have FULL (not partial like mobile 1 and so many other fakes) in the engine, transmission, and rear end. I even have it in the power steering pump, which runs much more quiet now. My preference is Redline synthetic fluids, which AMSoil who claims to be the best of the best of the best, is so scared of that they won't even test against. I spend a lot of time over at bobistheoilguy lol
2. Make sure your tune up is up to par. You just put in a new motor so I'm sure yours is.
3. A nice unrestrictive exhaust system. Think everyone knows that it frees up power and helps out a little with MPG.
4. Those E3 spark plugs. They've done tests that show a 0.7 increase in MPG in a wide range of vehicles. While that isn't even 1%, it almost is. And 1% will eventually pay off at these prices. Especially given the fact that they're spark plugs, and not really all that expensive. Not something I'd bother doing until I needed new plugs, but the day is going to come so why not get some that help you out a little bit.
5. Low rolling resistance tires. Michellin makes some good ones. Those are the ones I'd go with. Something else that you wouldn't buy until the old ones were wore out though. Just like the spark plugs.
6. As for engine mods, aside from headers... I really don't know. There are a thousand tiny little mods you can do, but in the end, the general consensus seems to be that they don't help out all that much. Or at least, that the cost of such mods would take years to realize your savings in MPG. Like say converting to a roller lifter setup. Or buying more efficient rocker arms. Or even indexing the spark plugs to point towards the intake valve. Or using floating pin pistons/rods. Different cam, advanced ignition, the list goes on and on. There are so many, many engine mods like that, that all claim to be a slight efficiency increase. Which, yeah, I assume would all finally add up to give you more power, and of course more MPG. But due to the overall cost of implementing all of them, it seems that you'd save a lot of time and money just doing the LS swap instead. Where you'd get most of those mods already in place, in a motor that you didn't even have to build.
7. I know someone will say it, so I'll say it. Keeping your foot off the gas. Although me personally, I never had a problem with that in one of these old trucks. I'm under no illusion that they were ever built for that. In fact from my experience, performance what the furthest thing from the engineer's mind when they designed these trucks. Its not a sports car so I don't drive it like one. I'm sure most of you guys probly don't, but I can still see some of you mashing on the pedal from time to time. I guess so you can hear it get louder but not actually go any faster? lol
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Little things like letting off the gas just before cresting the hill, letting the speed come down a bit, and coasting down the other side... stuff like that allows me to beat EPA by a pretty nice margin on my HHR, and would make a noticeable difference in our trucks, too.
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I just did my first mileage calculation. It's not as good as I hoped for but it is better then the 9mpg I was getting with the weak 350 I will post my numbers in the mileage section too. This is 95% city driving 532 miles/28.32 gallons =18.77 mpg and my truck really needs an alignment and tires. I put drop spindles on it and it has been pulling to the right ever since.
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So you're going to do an LS swap capt? That will be interesting to see. Are you doing a 5.3?
Yes, I started the process today. I am putting a 6.0L/4L80E in my 87 R10. Will be posting to both the Rides section for the removal process and start a LS swap in the Project section...
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Its a 366 cubic inch motor. I'm not certain, but is the 350 dead? Has the 5.7L been replaced with the 6.0?
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Depends on what you are talking about. trucks come with 4.8L standard, most opt to get the 5.3L
Corvettes come with 6.2L standard now.
5.7L engines are no longer produced in the LS series. At this time is has been replaced by the 6.2 on performance vehicles and 5.3 on everything else.
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261.6 miles, 17.285 gallons = 15.13 mpg
$3.29 per gallon = $57.02 to fillup.
Not sure what is happening here?
i've been looking further into diesels and i've found places that offer remanufactured 6.2/6.5's starting at $2300+$600 core. This could be a game changer.
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I am not sure if game changer is the proper word for a fuel that's been used for 60 plus years. I wish people i the US would start taking a hard look at diesel for a different fuel source until we could find an alternative especially in trucks. If you are looking at the 6.2 there are usually quite a few on craigslist under 1000. I couldn't imagine driving a non turbo diesel. Depending on how long you keep this truck and how much you felt comfortable spending. I would suggest looking into small computer controlled diesels. The new isf cummins is only available through import but you could probably get 35 mpg and have significant power. I would do your research if not for kicks alone and look into Mercedes and isuzu for transplants. If you are looking for gas mileage all I see is around the 20 mpg range with that big of displacement and very little power gains. You can learn a lot at 4btswaps.com. They have more then the 4cyl cummins. Have fun and plan to open your wallet. You will have a truck you will be proud of.
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Depends on what you are talking about. trucks come with 4.8L standard, most opt to get the 5.3L
Corvettes come with 6.2L standard now.
5.7L engines are no longer produced in the LS series. At this time is has been replaced by the 6.2 on performance vehicles and 5.3 on everything else.
So even the 6.0 is out now, when it comes to LS. Wow I'm behind the times. What series is the 4.8, if not LS? From wiki- "The GM LS engine family is an engine design intended as the only V-8 engine used in General Motors' line of rear-wheel-drive cars and trucks. The LS series was a "clean sheet" design with little in common with the classic Chevrolet small block V8."
Maybe they've changed their plans since then. Makes me wonder if the 4.8 would actually be the more economical choice for getting good MPG. Maybe it would result in better MPG than the 5.3LS
But wait, there's more. It looks like they also build some kind of 5.3L vortec motor these days. Which is not an LS, but may be easier to find in an all aluminum model.
"5.3 L
Vortec 5300
The Generation IV Vortec 5300 engines are truck engines that share all the improvements and refinements found in other Generation IV engines. At present, four versions of the 5300 are in production: two iron block versions (LY5 and LMG) and two aluminium block versions (LH6 and LC9). All versions feature the Active Fuel Management system."
The active fuel management system is what you were looking for stewart.
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AFM is a game-changer too. Wouldn't it be nice to find a shop that does nothing but LS conversions start to finish?
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Another thing that most people don't consider, which has a very dramatic effect on gas mileage, is aerodynamics. These trucks are about as aerodynamic as a brick sailing through the wind. Put it this way, at 60Mph, the average car uses HALF its fuel fighting the air resistance. Think of how much better mileage that car would get, if it could save half its fuel at 60Mph. That's how big the effect of aerodynamics is. You should see the awful, awful things they're doing to cars over at the ecomodding forum. They look hideous, but they see a big jump in MPG. I'm certainly not willing to go that far. The most I would do, is maybe come up with some of those covers that cover up half of the rear wheel, like some of those old cars used to have.
But not on my truck lol. Only on my toyota Yaris which already gets 35 MPG city.
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281.7 miles, 16.73 gallons = 16.83 mpg
$56.22 to fillup @ 3.359 a gallon Exxon.
i'm baffled why there is a 1mpg difference between this time and last.
2) i agree with aerodynamics. i'm a little short on time right now, so any further experimenting will have to be put on hold.
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Another thing you might try are those MPG helper things. Forgot what they're called but I'm sure you've seen one at some point. They help you change your style of driving. Its just a little screen that you mount somewhere and plug into... something. The wife's volvo S-80 had one built in from the factory. Tells you exactly how many MPG you are getting at any given time, or you can look at your average. I started using that thing and was able to see a 2 MPG increase. Mainly just because I stopped accelerating much to stop lights, and coasting down hills. Applying the brakes as little as possible. Stuff like that. The little readout starts showing your mileage going down the toilet when you accelerate and it makes you drive better.
A lot of those overpriced programmers have them built in these days, such as those "Bullydog" products and the like. Although, you can get just the gauge for much less.
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i have a link to one of those computers that i can dig up maybe later.
But i think the most basic thing which i don't think has been mentioned here is tire air pressure. i think a weekly check is reasonable. Although monthly could work also.
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Depending on whether your truck has OBD. The old-school method is to use a vacuum gauge so you could see what sort of engine load you have. They were (are?) sold as economy gauges, and work on older vehicles with carburetors.
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I don't know if this helps anyone, but I'll throw this in the mix...
My Dad had a '87 GMC R1500 350, 700R4 (don't know what rearend ratio) that he would usually get 20 mpg.
Additionally; while driving the straight, flat highways on the high plains, his '96 GMC C2500 350, 4L80, 3.73 would 20 mpg.
However, I rarely get over 14 mpg in my 2005 Chevy 2500, 4x4, NV4500 with 4.10's... And I've never got better than 12 mpg in either of my '70's GM trucks.
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But i think the most basic thing which i don't think has been mentioned here is tire air pressure.
I have been studying up over at the ecomodding forum. Its pretty common for those guys over there to overinflate their tires by about 5 psi. They say it gives you a small boost, while not really hurting the tire. They say that the old bias ply tires were the ones that were more prone to wearing funny when overinflated. Plus only going 5 PSI over doesn't do much harm anyway. But you gain a small percentage of MPG. Might be something I try out sometime.
I don't know if this helps anyone, but I'll throw this in the mix...
My Dad had a '87 GMC R1500 350, 700R4 (don't know what rearend ratio) that he would usually get 20 mpg.
Additionally; while driving the straight, flat highways on the high plains, his '96 GMC C2500 350, 4L80, 3.73 would 20 mpg.
However, I rarely get over 14 mpg in my 2005 Chevy 2500, 4x4, NV4500 with 4.10's... And I've never got better than 12 mpg in either of my '70's GM trucks.
I've heard a lot over the years about the TBI trucks being able to get 20 MPG if you do the right stuff. One of the things that some people do to them is raising up the throttle body. Some guy came into the tire shop I worked at as a teen, and he had some kind of weird looking, double throttle body spacer setup. He said his truck often got 22 MPG. Had some kind of weird looking open intake thing going on too. Now that I have one of the trucks I wish I knew who he was.
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Before the transmission went out on my 87, it always got 17/22 and it was completely stock, around town it was getting 20mpg.
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244.9 miles, 16.7 gallons = 14.66 mpg mostly highway miles.
$64 at exxon to fillup. i think sign price was $3.81 The reciept didn't print out fully.
i may start a part 2 as i want to get into aerodynamics but i can't promise anything.
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265.5 miles, 17.538 gallons = 15.13 mpg
$3.639 per gallon at BP
$63.82 total to fill up.
P.S. i've had to take my tonneau cover off temporarily for hauling reasons if that makes a difference.
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Wow. It's hard for me to believe the thread is almost 5 yrs old. i really need to get on it.
One thing we can see is that the price of gas hasn't really moved that much in that time. Gas around this time in 08 was over $4.
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278.6 miles, 17.411 gallons = 16.00 mpg
$3.479 per gallon $60.57 to fillup at mobil.
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274.2 miles 16.856 gallons = 16.27 mpg
$3.399 at sunoco, $57.29 to fillup
Mostly highway, some flat bar towing--the cavalier (2500 lbs.) and hauling lumber. Had the tonneau cover off the whole time.
Still much cheaper than buying a new silverado.
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1975 chevy Scottsdale camper special 454 3 speed auto. 8 mpg lol
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how are you getting 15-16mpg? i wasnt able to get better that 8.5mpg with the edelbrock i had on and since i put on a Q-jet but havnt gone through a couple tanks yet to confirm my average mpg but the last tank i got only around 10mpg.
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how are you getting 15-16mpg? i wasnt able to get better that 8.5mpg with the edelbrock i had on and since i put on a Q-jet but havnt gone through a couple tanks yet to confirm my average mpg but the last tank i got only around 10mpg.
Oh, any of these 1/2 tons can get 16-ish even with a 350. Here is how i'm "doing it:"
Tires no larger than 235/75 15's and make sure they are aired to at least 35psi.
2.56 rear diff gear TH-350C with lockup converter
2WD
STOCK 305 with STOCK 2G carb. i think the wilder the cam, the less mpg.
HERE IS A MAJOR THING------i accelerate gently and don't drive faster than 65. i think this is an important factor.
Sometimes i use a tonneau cover.
Have you confirmed that your odometer is reading correct?
My latest: 255.3 miles, 17.054 gallons = 14.97 mpg
$3.599 per gallon regular at mobil $61.38 total to fillup
i was doing a lot of hauling wood w/out the tonneau cover.
i am planning on starting an mpg pt.2 a.s.a.p. that will take it to next level.
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Yeah my truck is quite a bit different that yours. on mine i got 32X11.5X15 tires and filled up to 40psi. 3.73 gears in rear diff. then the sb 350 and a TH350 not sure on a lock up converter or what it is then 4wd and a quadrajet on top of engine with sp2-p intake and as far as i know engine is stock and i do try to accelerate gently and drive "softly" and i never am really on the highway very much up to even 60mph and the odometer i believe is correct, but how do you check it? never had a tonnueau cover just a tool box. and on my last take i average 11.35mpg which is a ton better than before. and that last tank included being out on the highway at about 70mph for 40 miles round trip and trying out the secondaries on the carb a few times just for fun. so im gonna try on my current tank to take it easy as possible and get the best i can.
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the odometer i believe is correct, but how do you check it?
you could always ask a cop to use his laser on you. but dont go by as fast as you can just what you think is the speed limit. had someone do that around here a couple years ago asked the cop to see how fast he was going the cop said yes. the guy flew by him as fast as he could in a 45mph zone. needless to say he didnt need his speedo calibrated lol
but that being said since you know your ratio and tire size you should be around 2800rpms doing 65. its a little high but its kind of right in the middle for performance and mpgs. 11 mpg aint bad for a 4x4 but i have a 350, holley 650 i think, w/ 4.10 ratio and a sm465 manual transmission so no slipping on the converter as you would with a auto. but it been a while but i think i was 9-10mpgs with 38s. now thats keeping it below 60 and easy driving
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Yes, i suppose that's one way you could do it (ha-ha!). Another way is if you have a speed sign that reads your speed and posts it up, you know the "Your speed is" type sign. These two ways can calibrate the speedo, but do not necessarily confirm of the odometer is reading correct.
i think the new GPS units are pretty accurate as far as measuring distance so that's one way to verify your odometer. Another way is to use the mile markers on the side of major highways. But don't just use one or two, use a lot of them.
What i'm using is a digital speedo/tach which also has an odometer and other functions. You may want to look into the new GPS speedometers or regular gps units. The prices are dropping.
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P.S. A lot of smart phones apparently now have GPS capability or apps.
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yeah stew that scares me. when i want a app that requires gps fine location i wont download it. you be surprised on how many applications are running on your phone and what they are doing. i hate having something running when it can track me or see what im doing. granted the phones can do this by default but thats not really something i can change but i can change certain apps
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ok i see what you guys mean by my odometer being correct i wasnt sure at first, but i do have one of those speedometer apps on my phone and it tells me my truck speedo is pretty accurate until i hit about 45 then it is slow as im really going 50( all based off of phone app) and it only gets worse the faster i go such as 55 is 64 and 70 is about 80 so i'm not sure what that can tell you. and i always thought their was a correcter for this on the transmission to compensate for larger tires( wouldn't my tires be the cause). Irish your are correct on the rpms at 60mph. oh and i already failed at keeping this current tank as the best i can get, because i just love to run those secondaries but only did it once to get onto the highway fast so should hopefully still be better than last tank. Also for the differential gears i think that they are 3.73 but i only think that from the sticker in the glove box. Unless someone changed them than that is what they should be.
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So, i take it your tires are not stock to the truck? i can't comment on the phone apps as i haven't used one yet. But i can say the actual standalone GPS units are pretty accurate as far as speed and distance.
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if the rpms are close i would say you do have 3.73. i wouldnt even know where to start guessing on the tire and the speedo gear. i know they make them for different rear ratios but not sure about tires. make sure you do have the 3.73 pop the cover off, im pretty sure you do but double check. BUT lets say you do have 3.73 ratio with 32" tires at your running about 2800 at 65. you would still be running 2800 at 65 with the stock tires 29" and a 3.42 ratio. sooooooooo with that said, if you buy the gear for the th350 and 3.42 rear ratio your speedo should be right.another but im sure theres a proper way of doing this and someone will chime in cause all im doing is guessing lol
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the gear you mentioned for the th350 you mean the compensator right. and I think the biggest factor I have is tuning in my carb a little better. I bought a new(remanufactured) q-jet online and they said the jets would be fairly close to the application, but may need finer tuning. so I think I need to get some new jets and go down 2 sizes from whats in their now and maybe even change the power piston. and I was also told that larger tires helps your mileage to a point until you have extremely large tires since the whole distance traveled per revolution is increased, but it may take more to set the wheels in motion.
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right about the tires. it essentially lowers your rear ratio number wise. like i said before your 32s and 3.73 is like running stock 29s with 3.42 ratio. about the carb i dont know what your talking about lol the gear i was talking about is in the tail shaft of the transmission. right now its set up for 29" tires and 3.73 but with your tires its like running the 29" tires and 4.10. so if you find a 4.10 set of gears/rears that would work but the cheaper way would be to find the gear in the tail shaft. never changed one or know anything about them just like doing math problems lol so my help is limited
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ok i think i see what you are saying. but im still gonna try the carb out first as that is more that likely the cheapest and probably the easiest and can make huge differences. And i will be getting my new tires pretty soon sometime next month when my uncle brings them from Missouri and they are 31X10.5 and in case your wondering why i have tires in Missouri when when im clear in utah. Well the story goes, this spring i went back out to missouri (when he was out here i road back with him) and i also took my dirtbike with me since he had just had a motocross track built. so their i was in missouri helping my uncle run a car dealership when the owner came around( my uncles brother in law) and he hired my to drive some cars back from the auction in springfeild and kansas city both about 2 1/2 hours away. so i made three trips first drive was in a 1988 chevy 2500( funnest to go 75mph on freeway) then a 2007 chevy 2500 both from springfeild and then a 2004 chevy 2500 with large lift and tires from kansas city.on top of it i was helping work on cars and change tires at the dealer ship for free. and one day i saw some goodyear mt/r tires that are brand new up in the corner of the shop and asked what they wanted for them and they told me they would give them to me for $300 which was an awsome deal. so i said yes but it will be awhile until i get the extra cash. Then a couple days go by and the owner calls me up while i was still in missouri and he tells me he'll just give them to me since i had been working at the dealership anyway for free. the day soon came for me when it was time to go home and my parents had decided to put me on a plane to go home instead of driving 1000 miles to pick me up since flying was more cost effective. So now i have a brand new set of tires for my truck and my dirtbike sitting in my uncles shop rotting away in missouri until he comes back out to go camping and to see by sisters wedding next month. All of this back in missouri was clear back in the end of May and First of June when i came back. So the exact same time i was in missouri is when that terrible storm hit Oklahoma then hit the town i was in the next day, luckily though no tornado's touched down when it hit me. quite the story huh:)
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sorry i feel i kinda hijacked your thread ill try to stay out of it more, i was just a little curious as to what you were doing different than me on your truck.
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theres only one way to know what hes done compared to you
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ya i guess thats true. you would have to have a bad example to show the effects and differences of a good one.
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sorry i feel i kinda hijacked your thread ill try to stay out of it more, i was just a little curious as to what you were doing different than me on your truck.
That's ok; i will get into more detail a.s.a.p.
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ok thanks
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sorry i feel i kinda hijacked your thread ill try to stay out of it more, i was just a little curious as to what you were doing different than me on your truck.
That's ok; i will get into more detail a.s.a.p.
i think the main things i'm doing "differently" are 2WD---4WD is a little heavier. Smaller tires and 2.56 rear diff.
273 miles, 17.254 gallons = 15.88 mpg
BP $3.529 per gallon. $60.89 to fillup
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This mileage is atrocious and WILL be dealt with.
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yeah i see what you mean. i know 4wd isnt helping me at all but i should still be getting a little better than i am. i am going to be going down a little in tires. and i am jetting my carb better once i get the time to do so. then well see how well it can do.
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284.1 miles/ 17.297 gallons = 16.42 mpg
$3.19 per gallon regular at Exxon. $55.33 to fillup
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i recently took my jets down to a #70 from a #72 and then the rods down to 51 from 52. and i also put in a softer power piston spring. its seems to be getting better mpg, i haven't checked it yet and probably wont for a while since its in the shop now getting ready for paint. I think that a next big thing for me to do is to upgrade the ignition system since im still running stock.
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274.3 miles/16.316 gallons = 16.81 mpg
$3.399 per gal regular Exxon. $55.46 to fillup
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284.1 miles/ 17.297 gallons = 16.42 mpg
$3.19 per gallon regular at Exxon. $55.33 to fillup
274.3 miles/16.316 gallons = 16.81 mpg
$3.399 per gal regular Exxon. $55.46 to fillup
So what did you do different to increase it .41 mpg, not drive as fast ?
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So what did you do different to increase it .41 mpg, not drive as fast ?
Not real sure. i probably did not sit in as much traffic. Also i put a new tonneau on at about 1/4 tank. i can't drive faster than say 55 because all my tires are either out of round and/or distorted (see other posts regarding tires. i am working on this currently).
i may start a new mpg thread, pt.2 soon. My goal is to get 20mpg. i think it's possible.
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286.4 miles / 17.183 gallons = 16.66 MPG
3.399 regular at Sunoco, $58.41 to fillup
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301.9 miles / 17.025 gallons = 17.73 mpg
$3.389 per gallon regular at Exxon, $57.70 to fillup
This time virtually ALL highway miles, i even went 74ish for a while because i was late one time. i also put a "new" tonneau cover on; i will describe it in another thread.
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260.7 miles / 16.740 gallons = 15.57 mpg
3.359 per gallon regular mobil $56.23 to fillup.
Definitely more stop and go traffic. i also want to say that for me and my personal situation i don't think not running a mechanical fan makes much a difference if any with mpg.
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291.3 miles / 17.76 gallons = 16.40 mpg
$3.329 per gallon regular at mobil $59.14 to fillup
Tonneau cover is currently off because i had to dump a lot of trash and now i need for the sun to really disinfect the bed.
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283.8 miles / 17.415 gallons = 16.29 mpg
$3.299 per gallon regular at Shell, $ 57.45 to fillup
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294.8 miles 17.533 gallons = 16.81 mpg
$3.399 per gallon regular at BP. $59.59 to fillup
i am now using a grill block and tonneau. More detail in the 2nd mpg thread.
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Have you looked into HHO kits?
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What's HHO kit?
276.6 miles/ 16.988 = 16.28 mpg
$3.339 per gallon regular at Mobil, $56.72 to fillup
The grill block not only does not seem to have any benefit to mpg, but actually hinders mpg as i had mostly highway miles this tank. i think what may be happening is that the fan is engaging constantly; i will provide more details and pictures in the next thread.
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I remember years ago someone put a nose on their truck or car it added mpgs
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HHO is a Hydrogen Oxygen mix that is produced by a generator mounted in front of your radiator, ran through a reservoir, then a dryer and right into your intake. It is essentially an additive that replaces the gas used. I have one on my 2007 Altima and have run three tanks of gas through it. Haven't seen a huge jump in mpg but I am still adjusting the EFIE controller mine requires. I have to trick my o2 sensor into telling my engine to ask for less fuel. My mpg has had a small increase but has been more steady regardless of where I refuel.
In a carbureted engine I think you plug the hose right into the intake somewhere and then retard the timing to account for the vapor. Do some research on it. Browns Gas is another name for it. I ordered my kit from www.hhokitsdirect.com. A three person company out of Antioch,California. So far I have been happy with there customer service. A few of the dryers I was sent cracked to due engine heat and he replaced each at no charge and finally got me one of a different design that has allowed me to finally get into adjusting it.
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not bashing what you have found to work edemuch but when someone says
"RETURNS/REFUNDS:
You can return your HHO Generator within 30 days of purchase for a full refund of purchase price* as long as the unit has NOT been installed, filled with electrolyte and/or been turned on and/or used in any manner. Taking apart or disassembling the hho generator or bubbler voids all warranties and refunds. If you have installed the kit in your car, you may NOT return it for any reason EXCEPT warranty repair- no refunds issued after installed in vehicle or used in any manner." thats scary when you just spent $500-$900
i tend to stay away, i mean when i drive to work i get about 19-25 mpgs going 65mph about 25min. when i drove to look at trucks going 75+ mph i get 29-32 mpgs.
even this looks funny
(http://www.hhokitsdirect.com/images/mileage-results.jpg)
look at the 5th one down the cat, they report a lose yet it shows increase same deal with 10th one down. now granted i can understand getting the numbers mixed up but the 15th one (silverado) shows no before or after yet a 42% increase
their website is based mostly of jpg images, seams too "infomercial" to me. the logic seams to be there and i could see this working for a fuel injected car due to the ecu taking over. but in a carbed motor i dont see how it would work well. yeah you can get it tuned when at idle but then get to highway speed and you will prob be running too lean cause you based your cab settings off a setup at idle
Not saying this is a scam or edemich is full of it. what im saying this is a buyer beware type of situation.
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I am not saying it's for everyone. Lots of skeptics with this stuff. From my experience the guy seems on the level. The kit is not built cheap so it appears it is worth at least most of what you pay. Just thought it was a viable suggestion for someone who was trying to hyper mile a V8. I drive 180 miles round trip to work every day so I figured it was a worthy investment if it worked. Just a 3 mpg gain for me is a big savings in a few months of driving. Again this is on a Nissan Altima.
It's sort of ironic because my truck will be lucky to have double digit gas mileage when I start driving it!
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293.4 miles / 17.776 gallons = 16.50 mpg
$3.299 per gallon regular at Shell, $58.64 to fillup
i'll update on the grill block as soon as i'm able to. i used chloropast. Right now, it seems to have NO positive effect on mpg.
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262.5 miles / 16.912 gallons = 15.52 mpg
$3.699 per gallon regular at Exxon, 62.56 to fillup
Really not sure what is going on here. i did get stuck in a big traffic jam though so that may have something to do with the below average, for me, MPG.
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I think i get around 9-11 miles per gallon lol
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I don't know my crew cabs mpgs yet. First test I got 11-12 mpgs on the left tank. The part that doesn't make sense is for the right tank I got 14. After that I unhooked my speedo cause I have a millage limit for my inspection. But I had a couple gallons in each tank the other day and was able to fill both sides up for $100, must be election time again 3.03/gal
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$2.94 regular here near the city.
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Now down to $2.89 per gal regular at mobil.
Although there probably will not be any mpg reports from me for a while (see other post regarding engine) :'(
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212.6 miles/17.181 gallons = 12.37 mpg :(
$1.639 per gallon regular at Mobil, $28.16 to fillup
This is the first serving with the "new" 4.3 v-6. Yes your big block gets better mileage, but for this tankful i was still trying to get everything sorted out and to just get the thing running. i had 3 different carbs on the engine finally settling with a reman jegs quadrajet. There were a few fuel leaks while getting everything setup, one of the carbs, the 2G flooded out the top and i decided that one needed to be rebuilt. The first quadrajet, that came with the engine, is probably junk, totally wrong for the application and just didn't run very well.
There was lots of idling and low speed testing.
i've since got the "new" reman quadrajet running ok to pretty good, finally getting around to adjusting the idle mix screws---these have the funky "double d" heads on them. So i've leaned down the idle a bit.
i've also put in new plugs. The plugs that came with the engine have been in there a while.
So hopefully next tank will bring some improvements.
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249.6 miles/ 16.328 gallons = 15.29 mpg :(
$1.749 per gallon regular at mobil, $28.56 to fillup
A little improvement, but still not quite there. Even the 350 got better mileage. i still think i'm rich on the idle circuit---i didn't use a vacuum gauge just did it by ear and tach. Also one of the idle mix screws is partially blocked by the EGR valve and it was hard to get to.
But i think it's more important to right now to get the fan wired up because it's getting warmer around here. Then i can get to the idle screws again.
Anyways, in the meantime here are the specs on the "new"/(reman actually)carburetor and tell me what you think:
Jeg's model #15805 with the .073 jets and 50M primary metering rods.
http://www.jegs.com/i/JEGS-Performance-Products/555/15805/10002/-1?parentProductId=
i chose this one because i thought it would be the closest to stock. It does seem to idle and run well.
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whats wrong with 15 mpg?
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whats wrong with 15 mpg?
Because even the 350 and the 305 with 2 barrel got better than that----up to 17 and half sometimes.
This is the "new" 4.3 v-6 remember?
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250.0 miles/ 16.362 gallons = 15.28 mpg :(
$1.899 per gallon regular. $31.07 to fillup at Pep-Up.
Still working on carb tuning. i think this engine is tired and needs a rebuild.
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whats wrong with 15 mpg?
Because even the 350 and the 305 with 2 barrel got better than that----up to 17 and half sometimes.
This is the "new" 4.3 v-6 remember?
I think you answered your own wondering here...
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253.0 miles / 15.738 gallons = 16.07 mpg
$1.999 per gallon regular at Sunoco, $31.46 to fillup
A little better but still not quite there. Adjusted the choke pulloff.
i got the idle mix screws about as lean as i can go. i think this engine is tired, worn-out and needs to be rebuilt. It's 30 yrs old after all.
But i can't switch for a few months due to time/money etc.
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also stew you will see a better mpg once they switch back to the summer blend. i know my imp is ussaly around 23 with the winter and 28 summer or something like that
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also stew you will see a better mpg once they switch back to the summer blend. i know my imp is ussaly around 23 with the winter and 28 summer or something like that
Hopefully.
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Bump your tires air pressure up a bit more. Running full sidewall pressure makes for a rougher ride however and possibly over-inflation too.
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265.7 miles / 16.826 gallons = 15.79 mpg
$1.959 per gallon regular at Mobil. $32.96 to fillup
This is just sad. i don't think this engine was very well maintained. It still runs ok though.
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stew think about the power:weight/drag ratio. theres a reason why my mpgs went up when i put a bigger motor in my crew cab, i went from a gas 350 to a diesel 360. im making more power at the lower rpms to get up and moving and my power band is 160 hp at 2500 400 ft lbs at 1600. now these numbers are stock and for a new motor. but i should be around there. im cruising around 1800 rpms at 62 mph she seams happy just to cruise with little effort there. nothing after the engine has changed except i gained a few hundred pounds (cummins is about 1100 lbs). im not sure if its cause im not past my hp band or if its im cruising at my tq band. want to say its my tq band, but shes happy right there. maybe you need to find your tq band and see where that will put you. remember after 55 youre fighting wind more than your weight and tire drag.
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I always heard that a stock 350 likes about 2200 rpm cruising. Can't say how accurate that is. I think 15mpg for a old 350 engine is pretty good. If you want better disconnect the four barrel side and only run two barrels. Or swap a small two barrel onto it. There is only so much that can be done realistically though. These engines are caveman parts compared to today's engines. For the best mileage you need to open the bottom, install a windage tray and wiper setup, remove the water pump drive and make it electric, add electric fans, put synth in the transmission and rear end, buy hard compound tires, get a really good ignition system with multi-spark box, remove as much weight as possible, cover the bed or remove the tailgate, etc. Each by themselves does little to nothing, added together it might get you another 1.5 mpg. Of course, the cost will blow that savings out of the water.... ;)
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You're forgetting that he swapped the 350 out of his truck and put a 4.3 v6 in its place. I used to get around 16 to 17 mpg out of my 4.3 but that was in my S-10's! So your truck getting 15 is actually pretty good considering there's more weight to move around! I tend to get around 13 mpg out of my 350, maybe 14 if I drive it like an old grandma! These trucks were never built for efficiency, they were designed to work and haul loads! As much as we love them, they have the aerodynamics of a brick on wheels! Lol!
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if it makes you feel any better my 02 chevy with a 4.8 ½ton only gets 16
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When gas was 100% I got 15-16 with my 454 4 speed with a 3.21 rear end. That was when the speed limit was 55, I drove as if I had an egg between my go pedal and foot. The 4.3L that was in my 86 got maybe 14 on the trip home from when I purchased it. It ran good but it seemed like I had to really mash the pedal to keep it at speed, that was a 3 speed manual with a 2.73. My 4.1L is getting 15-17 on the highway with the same trans and rear end in my 84 but pushing 70mph. That truck has a topper and 70 series tires
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I find this talk about mpg very interesting now that I just accepted a job offer in downtown Phoenix which is 30 miles from my house and gas just got back to 2 bucks here. Yet I love driving my truck (brick) so I will pay for the gas while doing what I can to save it. I pay very close attention to the shift points while watching the tach. When I can go 65 mph while doing 1900 on the tach I think I am doing okay at saving money on gas.
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I guess I did miss the part about the swap. As an old timer I see mass as the only thing to get these ships moving, that would be the mass of a v-8 crank and flywheel. ;D I know these trucks came stock with I-6 engines, and they were good engines, just don't even try to drag race a fully loaded Conestoga wagon with two ponies pulling it, you will lose every time. What you could do with those I-6's is pull a dozen of the Conestoga wagons over Donner pass in a snowstorm all at once. I see the v-6 as an entirely different animal. It's not a good high torque puller, it has no mass for it either, but they also don't have great high rpm horsepower. They are what might be called eunuchs of the automotive world. They do get good fuel mileage if the power to weight ratio is in their working parameters.
With that said, I had a new 2000 Silverado with the v-6. It was an awesome truck. But it was a standard cab, step-side. It got 20mpg easy. But it was a finicky drinker, the fuel injectors clogged every six months and had to be replaced each time. I got tired of that and sold the truck. Iowa is (was anyway) notorious for dirty fuel. It was hard to get brand name fuel around here though, just convenience store fuel.
OK, I digress....
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276.5 miles/ 16.666 gallons = 16.59 mpg
$2.119 per gallon regular at Exxon, $35.32 to fillup.
Improving, but mostly highway miles. And it's still lame because the 350 and 305 both could get 16.5mpg doing mostly highway miles without even trying.
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i'm thinking of starting another mpg thread to keep things better organized, until then:
300.1 miles / 17.489 gallons = 17.15 mpg
$2.199 per gallon regular at Exxon $38.48 to fillup
That's more like it. Still tweaking the carb.
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whats wrong with 15 mpg?
Nothing, my Crown Vic gets 16mpg :'( even worse my K10 got around 9mpg mixed driving the one time I tracked it. :'( :'( :'(