73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: Tazman on April 26, 2011, 07:51:19 pm
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My truck is a daily driver and God knows I love driving it as much as I can.Yet with gas getting out of hand I need to get better milage.I drive 55 take it easy always and get 17 to 18.5.It has a stock 350 with the 700r trans auto.Any ideas how I can stretch that milage a little more?Thanks
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not much besides keeping it tuned up as best as possible and keeping a light foot.
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You're already getting pretty good mpg's for your combo. Keep up what you're doing.
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Tow it with a cummins.
Seriously, you're doing pretty good as it is. What jaredts said.
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-Bed covers are supposed to help a little.
-Or you could open or remove the tailgate.
-A vacuum gauge will help your driving habits if you pay attention to it.
-keep your tires inflated properly.
-I wouldn't mess with the engine at all as you are getting pretty good mileage already.
-synthetic fluids can help some.
-get rid of any unnecessary weight.
-keep your air filter clean.
-all in all your best tool is using your right foot a little less.
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You're ahead of the game...
My 06 trailblazer gets 10-12 around town.
My 87 K5 gets 10-12 around town...
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I've learned a bit about hypermiling from driving a Prius. Use the throttle like you have an egg between your foot and the accelerator pedal. Is your air dam installed below the bumper? I've read that this will actually give you an extra mile or two
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Geez... if mine got what yours is getting I'd praising the Good Lord! Not sure what else you are going to do other than just keep on keeping on.
What rear end ratio do you have? I have an 88 Corvette with and L98-350 (multi-port injection) with (believe it or not) 2.59 rear gears. I have thought about swapping them out for something stouter many times, but I gotta admit, the 20mpg I get around town (driving it however I dang well please) and the 25 or so I get on the open road is pretty dang nice... especially nowadays.
Anyway, that would probably be the next step, but it won't be cheap.
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You're doin better than a lot of new trucks. Just go with it man.
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There's probably not much you can do engine wise with the 350 to increase your fuel economy. So at this point, your best bet would be to work on the aerodynamics. These trucks are super boxy so there's actually a lot to be gained there. 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.
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Impressve mileage for a tough truck.
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I don't know what I'm getting out of my '77 3/4 ton full-time 4x4 but I KNOW it's a LOT worse than that! 18.5 is decent.
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yes, very impressive numbers
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i spent $468 on food last month and about $128 in gas.
Track how much you spend in food vs. gas, then report back.
My point is look at the big picture----- 17-18 is pretty good for a pickup. i assume it's paid for? So, you're total cash output for this truck is not as high as you might think.
We all do want to get better mpg though; You may want to check out my in depth mpg thread, which i admit i have updated in a while.
P.S. i think if your total transportation costs anually exceed 5% of your gross income you have a problem. Obviously you want to get this cost as low as possible, but i think 5% is a reasonable number.
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very well said
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You're doing great with those numbers. Mine is an 87 as well but with the 305 and gets the same mpg as yours.... but you probably have lots more power with the 350.
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i spent $468 on food last month and about $128 in gas.
Track how much you spend in food vs. gas, then report back.
My point is look at the big picture----- 17-18 is pretty good for a pickup. i assume it's paid for? So, you're total cash output for this truck is not as high as you might think.
We all do want to get better mpg though; You may want to check out my in depth mpg thread, which i admit i have updated in a while.
P.S. i think if your total transportation costs anually exceed 5% of your gross income you have a problem. Obviously you want to get this cost as low as possible, but i think 5% is a reasonable number.
This is the voice of wisdom of here. We're saving money driving an old vehicle like what we've got over paying payments on a new vehicle. However, you can improve your fuel economy by installing a lip on your bumper and extending it down almost to the ground. The next thing would be to install a cover that angles downward from the cab down to the tail gate. Or you can do like me and just drive 55-60 mph on the highway. At 60 mph, my Suburban diesel will get 27 mpg but if I drive 80 mph, the fuel economy plunges to 18 mpg due to the poor aerodynamics.
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I think one time Vile posted a picture of a truck with a fiberglass bumper cover the looked like ground effects. I'll bet that would help with what the guys were saying about lowering the bumper and making sure your air dam is installed. If you keep the air out from underneath, it will help out. You get all wild and maybe tape off some the front grill like NASCAR guys do for qualifying :-\. It would probably help the aero but it would look strange. :-\
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Here are several truck that were ecomodded to the extreme to give you an idea what I was explaining.
--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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delete
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That poor, poor Dodge. If trucks had emotions, I'm sure it would be humiliated.
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hahaha
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Also investigate natural gas conversion. i think it's $2.30 a gallon now.
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Also investigate natural gas conversion. i think it's $2.30 a gallon now.
It's even a lot cheaper than that if you have natural gas at your home. However, you would have an initial investment of about $2000 for the high pressure pump and how ever much it costs to retrofit your vehicle. Where I live out in the countryside, it's unavailable otherwise I would have gone this route a long time ago. However, the reason the public is not buying into it is because only a few cars are appropriate for running on natural gas. The retrofit adds a considerable amount of weight to the vehicle due to the extremely heavy tanks. However, it would work like a charm on our trucks especially if they're 3/4 ton and have a big block engine.
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I've put my '90 gmc 4x4 on dual fuel (gas/propane) the day after I bought it. The mileage is a bit less on propane, but over the years it's been about half the price of gasoline. Right now gas is $1.31/litre ($6) and propane is .61; I run propane probably 98% of the time.
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I've put my '90 gmc 4x4 on dual fuel (gas/propane) the day after I bought it. The mileage is a bit less on propane, but over the years it's been about half the price of gasoline. Right now gas is $1.31/litre ($6) and propane is .61; I run propane probably 98% of the time.
Unfortunately, propane is hardly any cheaper here in the states. You could gain back a lot of the mileage by upping the compression but then it would run horrible on gasoline.
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How much is propane there? I do have 10:5 compression on my '90, but I install a dual curve ignition and it's set up very nicely to adjust timing between the two.
Here's a pic of it, the blue box on the left is the dual curve box:
(http://i2.photobucket.com/albums/y8/JohnnyCanuck62/P1030168.jpg)
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UPDATE:
Food $287.48
gas $93.40
rent+utilities over $950
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UPdate: New strategies for increased mpg, in my opinion:
Think ----higher compression and/or cam---mega rv type cam with massive bottom end torque and no top end.
-----jet down smaller in the carb.
-----electronic fuel injection is getting a little cheaper.
-----keep it at or below 65mph.
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UPdate: New strategies for increased mpg, in my opinion:
Think ----higher compression and/or cam---mega rv type cam with massive bottom end torque and no top end.
-----jet down smaller in the carb.
-----electronic fuel injection is getting a little cheaper.
-----keep it at or below 65mph.
Wouldn't a higher compression ratio and high lift cam by themselves lower mpg's? If you did those two things to allow you to run an ultra high gear maybe?
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Wouldn't a higher compression ratio and high lift cam by themselves lower mpg's? If you did those two things to allow you to run an ultra high gear maybe?
Higher duration cams usually lower mpg's but not high lift. High lift cams help with breathing.
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UPdate: New strategies for increased mpg, in my opinion:
Think ----higher compression and/or cam---mega rv type cam with massive bottom end torque and no top end.
-----jet down smaller in the carb.
-----electronic fuel injection is getting a little cheaper.
-----keep it at or below 65mph.
I would also add aerodynamic mods. There's much more to be gained with aerodynamic mods on our square trucks than with the powertrain. I would start off with the simple first such as:
-----Lower resistant tires (think tall and skinny)
-----Lowering the vehicle
-----Extending the bumper down
-----Canopy that angles down towards the rear
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i swapped in a 468bbc in my 79 malibu(brick square nose) over the 305sbc i had in there... town mpg nearly doubled and i picked up ~2mpg on the freeway i avg 18-19mpg @ 75
dynod it it does 305hp @ ~4800 and 435lb@~2400 i still have oem 2.41 gears i cruise about 1900rpm
short duration big lift create torque and inproves effciency.. hydrualic roller cams are the best for that... but thats ~1000.00 to retro fit a gen 1 block... simple conversont would be find a 88-98? gen 2 or 1 piece main block that had a hr cam already in it.. flywheel bolt patern is the only real difference.. some had mech fuel bose newer ones dont.
anything more need a diesel 6.2/6.5 or dmax swap 6.2/5 work very nice in DD applications and put out almost with peak tq about 2000rpm.. on most the the vairants. you arent goign to go very fast but you will pas alot of fuel stations.
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sounds to me like your where you need to bed! there is not much you can change to make a difference really! i get 15mpg in my 454/th350! it feels real nice getting as good as mpg as some newer trucks!
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Wish I could get that kinda mileage! I get about 11MPG average! 350/TH400 combo with 4.10 gears (K20). Leaning heavily toward a higher gearset since I don't tow often enough to need the 4.10's.
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You guys are all lucky. My truck gets 8 on a good day. 350, stock qjet, sm465, and 4.11's. It usual gets 6 or 7.
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I checked my mpg today for the first time in my '80 2wd swb.
355 cid, crower torque beast cam, flat top pistons, vortech heads, efan, no a/c,
holly street avenger; jetted f-68 r-72, edelbrock performer vortech intake, 1" spacer, timing 32 degrees advanced,
vacuum advance connected, no egr or any polution emission stuff, flotech headers, 2.5 magnaflow dual in/dual out exhaust,
dyno tuned to 393 hp and 432 tq peak
nv 3500 5 speed trans.
lowered 2/4, bed cover.
trip of 104 miles combination interstate, hwy and city driving equaled 20.9 mpg today.
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1980c10, what rear end ratio are you running?
I'm running a 383 with somewhat dished pistons with vortec heads, isky 264 megacam, quadrajet carb, 1" spacer, should be close to the same timing and getting less than 8 mpg. I'm going to try a new coil and maybe pull the module to see if the coil damaged it somehow. I've got a 700r4 and 2.73 gears but I've been driving in 3rd to keep the RPMs up but the MPG has gone down.
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I don't know what ratio i have but it's probably pretty high(it's stock) as i can pull 65+ in second gear. This truck is still a work in progress, getting to the rearend sometime as I need to replace the pinion seal and a few other things-so I will check then.
You do have a little more cam than I do, more cubes, less compression and an automatic transmission.
Why you would want to keep the rpms up?
Do you have your vacuum advance hooked up?
Is you spacer open in the middle? Mine is open and is a phenolic spacer.
What spark plugs are you running?
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in my 79k20 i have 4.10 and a 350/sm465 with that set up when i had my 38x16x16 i was running about 8 or 9 i switched it to 37.5x12x16.5 now im 11. next mods will be electric fans and cleaning out the tool box of all the unused junk
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1980c10,
Actually, our compression is fairly close at 9.4 to 9.5:1.
The cam makes more torque at higher RPM and the overdrive can cause a too low of an RPM to generate sufficient vacuum to keep the carb out of enrichment.
My vacuum advance is hooked up to manifold, I may switch to ported.
I'm running some kind of autolite plats for vortec heads. My spacer is a four hole spacer for the qjet.
I'm going to see if I can get an external coil adapter and get my module checked. That should eliminate some doubts.
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TexasRed
just some thoughts
I forgot to mention I am running flat top pistons with 4 valve reliefs. I estimate a 9.7+ to 1 CR
when I had the engine on the dyno is when I added the open spacer. the object wasn't to streemline the air or to create more space.
The objective was to even out the right and left banks air fuel ratio and it did also added hp.(one bank was running lean and one was running rich)
I don't see any reason you couldn't use an open spacer with the q-jet.
btw at 65 mph I am running pretty low rpms at 50 Is borderline for having to downshift.
Also I am running a/c delco platinum plugs (probably very similar to what you are running)
Why are you having doubts about your coil? Anytime i have had a bad one it was very noticable.
Just a thought also check your choke to be sure it is completely opening.
also note that my truck is a non a/c truck, the only acc are the water pump, alt and ps pump.
I also was running 91 octane fuel-(don't know if this hurts or helps)
my dist is a Proform hei and wires are msd streetfire.
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Didn't mean to hijack the thread.
Well, I suspect the coil because it's one of the few things that hasn't been replaced yet. It's a jeg's high performance one. I read on another forum that you really can't test them with an ohm meter anymore and it can cause the module to fail which mine was bad but the engine still ran. So I'm thinking it caused the earlier module failure and maybe causing it's replacement to fail. I need to pull the module and get it checked, then I'll be pretty sure.
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If you weren’t supposed to test them parts stores would touch them. Cause then the whole reliability thing would be pointed at them. Never had a coil work but not be good they either work or not but temp also affects that, that’s my experience with them. Now i would point more towards plugs wires. But pretty much anything in the coil can be tested.
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New MSD wires.
The module failed. Now I'm collecting parts to convert to external coil.