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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Stewart G Griffin on August 27, 2016, 12:07:09 PM

Title: MPG, Part 2
Post by: Stewart G Griffin on August 27, 2016, 12:07:09 PM
320.6 miles / 17.010 gallons = 18.85 mpg
$2.199 per gallon regular at exxon,  $37.40 to fillup

Now that's more like it.  Not all highway miles either.   i still think there is plenty of room for carb tweeking.  Runs ok though.

New setup:
GM reman 4.3 v-6  LB4  roller lifters, 9:1 compression
Jeg's reman quadrajet #15805
TH-350C trans
2.56 rear gear
235/75-15  Hankook Optimo 727's
Single stock exhaust---stock exhaust Y then rest of exhaust cobbled together with flexpipe and stock type muffler.
Title: Re: MPG, Part 2
Post by: Irish_Alley on August 27, 2016, 01:13:16 PM
do you have a fan on it this time?
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on August 27, 2016, 05:40:09 PM
Yes, definitely----a 14" Spal electric.
Title: Re: MPG, Part 2
Post by: redhot1.4 on August 28, 2016, 05:46:29 PM
My goal is to get my 78 to at least 16mpg.im currently best at 11 mpg. .. Is it possible I have a 350 with a th350 1,2&drive lol
My next upgrade is electric fans

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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on August 28, 2016, 06:48:52 PM
My goal is to get my 78 to at least 16mpg.im currently best at 11 mpg. .. Is it possible I have a 350 with a th350 1,2&drive lol
My next upgrade is electric fans

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i think it's possible, but tell us more.   Also, i don't think electric fans are going to make that much a difference if any, UNLESS you have a fixed fan.   The only reason why i went with electric was to save space and it's not easy to find a shroud for my application.
Title: Re: MPG, Part 2
Post by: redhot1.4 on August 28, 2016, 06:51:43 PM
Plain 350. With the new eps edelbrock performer intake manifold and new 600cfm edelbrock carburetor headers dual exhaust

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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on September 06, 2016, 09:49:55 PM
Plain 350. With the new eps edelbrock performer intake manifold and new 600cfm edelbrock carburetor headers dual exhaust

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What differential gear do you have?


275.7 miles / 17.945 gallons = 15.36 mpg
$2.119 per gallon regular at Shell, $38.03 to fillup


It turns out the choke was not adjusted properly as i had previously thought;  It would get stuck on low-mid step for too long and not go down to curb idle for a good 10-15 mins.   i did not really notice this for the previous tankful because it was mostly highway driving.

Also my tires were pretty low.  My other inflator broke, so i got another one.

So hopefully, the next tank will be better.
Title: Re: MPG, Part 2
Post by: redhot1.4 on September 06, 2016, 10:04:15 PM
Plain 350. With the new eps edelbrock performer intake manifold and new 600cfm edelbrock carburetor headers dual exhaust

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What differential gear do you have?


275.7 miles / 17.945 gallons = 15.36 mpg
$2.119 per gallon regular at Shell, $38.03 to fillup


It turns out the choke was not adjusted properly as i had previously thought;  It would get stuck on low-mid step for too long and not go down to curb idle for a good 10-15 mins.   i did not really notice this for the previous tankful because it was mostly highway driving.

Also my tires were pretty low.  My other inflator broke, so i got another one.

So hopefully, the next tank will be better.
Gears I don't really know.  I'm running a 285 75 16 tires.  It's a tall tire. I wanna say at 26 2700rpm I'm going 70mph
I was trying to up the rear end with a tall tire. I'm driving 56 miles round trip on the old truck all highway with a total of 3 stop signs and 2 red lights total.

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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on September 13, 2016, 07:51:58 PM
322.6 miles / 18.232 gallons = 17.69 mpg
$2.559 per gallon v-tech (premium) at shell.  $46.66 to fillup


i accidentally pushed the v-tec (premium) button at the pump because i'm not use to filling up at Shell.  i normally get regular.


Lots of idling this time;  The traffic situation around here just is not working out anymore.  :(

Got the choke adjusted right.  Engine runs better than ever.

Title: Re: MPG, Part 2
Post by: zieg85 on September 13, 2016, 10:21:11 PM
322.6 miles / 18.232 gallons = 17.69 mpg


not to shabby for a bunch of slow traffic
Title: Re: MPG, Part 2
Post by: zieg85 on September 13, 2016, 10:24:07 PM
If you ever need a trans go to a 700R4.  1st. gear would be easier to get the truck moving requiring less throttle.  OD may never be needed unless you hit 85
Title: Re: MPG, Part 2
Post by: LTZ C20 on September 13, 2016, 10:36:11 PM
If you ever need a trans go to a 700R4.  1st. gear would be easier to get the truck moving requiring less throttle.  OD may never be needed unless you hit 85
85! With a 700, you can go 35 in OD, you can go 40, 45 in OD and lock up. Some even go into lock up in 3rd.
Title: Re: MPG, Part 2
Post by: zieg85 on September 13, 2016, 10:44:25 PM
If you ever need a trans go to a 700R4.  1st. gear would be easier to get the truck moving requiring less throttle.  OD may never be needed unless you hit 85
85! With a 700, you can go 35 in OD, you can go 40, 45 in OD and lock up. Some even go into lock up in 3rd.

He has a 2.56 rear.  Final drive would be 1.87... probably idle down the road at 45
Title: Re: MPG, Part 2
Post by: LTZ C20 on September 13, 2016, 10:52:21 PM
If you ever need a trans go to a 700R4.  1st. gear would be easier to get the truck moving requiring less throttle.  OD may never be needed unless you hit 85
85! With a 700, you can go 35 in OD, you can go 40, 45 in OD and lock up. Some even go into lock up in 3rd.

He has a 2.56 rear.  Final drive would be 1.87... probably idle down the road at 45
Oh what a drag. In my opinion 3.73 and 4.10 gears are the only 2 worth using, they are the only 2 GM still puts in new trucks.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on September 22, 2016, 08:46:16 PM
326.3 miles / 16.736 gallons = 19.49 mpg
$2.259 per gallon regular at Exxon,  $37.81 to fillup

Even though there was much less idling this time, this might not be super accurate because i filled up at a different station---the previous two times was Shell and i normally use EXxon.   The pumps at shell are much slower and may allow more fuel to be pumped into the tank?

However, i do sense things are improving overall;  The engine continues to run smoother---i think it is still breaking in more.
Title: Re: MPG, Part 2
Post by: Irish_Alley on September 22, 2016, 11:38:39 PM
might be the pumps or it might be the quality of gas. need more test cause right now its only a variable and not a consistent
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 03, 2016, 06:41:44 PM
302.1 miles / 17.464 gallons = 17.29 mpg
$2.199 per gallon regular at Exxon, $38.40 to fillup
Title: Re: MPG, Part 2
Post by: MrFiveOh on October 04, 2016, 08:23:27 AM
302.1 miles / 17.464 gallons = 17.29 mpg
$2.199 per gallon regular at Exxon, $38.40 to fillup


Get an app called fuel log. Works really well.
Title: Re: MPG, Part 2
Post by: redhot1.4 on October 05, 2016, 07:43:17 AM
Do you think a new carrier bearing will improve mpg. We will see tomorrow morning when I fill up.

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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 05, 2016, 07:44:47 PM
Do you think a new carrier bearing will improve mpg. We will see tomorrow morning when I fill up.

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Unless something was wrong with the old one, then no.  i think there are new ceramic type bearings which are supposed to produce less friction, but even then i don't think it would make a significant difference.
Title: Re: MPG, Part 2
Post by: redhot1.4 on October 05, 2016, 09:02:35 PM
Yes sir. My carrier bearing was in bad shape

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Title: Re: MPG, Part 2
Post by: redhot1.4 on October 06, 2016, 08:49:36 AM
Do you think a new carrier bearing will improve mpg. We will see tomorrow morning when I fill up.

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Unless something was wrong with the old one, then no.  i think there are new ceramic type bearings which are supposed to produce less friction, but even then i don't think it would make a significant difference.
What a bust. Not even a little  bit improvement.  I'm betting electric fans and an Overdrive is the only thing gonna help my mpgs

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Title: Re: MPG, Part 2
Post by: 79 Royal Sierra on October 06, 2016, 08:54:27 AM
When I switched from my crappy cast power glide to a 700r4 in my 61 Impala it doubled the gas mileage. Other then driving really slow there is not much that will make it get any better mpg.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 08, 2016, 09:31:29 AM
In the meantime, here is an interesting read concerning MPG, specifically regarding RPM:

http://www.oldsmobility.com/old/carlife_apr67.htm


2) i've noticed that the newer trucks, silverado tundra etc. have much larger cabs and are much taller than the squares.  So if a square was to get an LS it should produce wonderful mpg?
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 11, 2016, 07:28:18 PM
300.5 miles / 16.778 gallons = 17.91 mpg
$2.249 per gallon regular at Mobil.  $37.73 to fillup


i think my air filter may be clogged (the cheap Mr. gasket unit i bought just to get the truck running).  i don't have time to look for a new one right now.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 22, 2016, 09:45:14 AM
292.1 miles / 17.175 gallons = 17.00 mpg
$2.199 per gallon regular at Mobil,  $37.77 to fill up
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 29, 2016, 07:46:39 AM
287.2 miles / 16.313 gallons = 17.60 mpg
$2.169 per gallon regular at mobil,  $35.38 to fill up
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 08, 2016, 07:46:11 PM
298.6 miles / 16.43 gallons =  18.17 mpg
$2.149 per gallon regular at Mobil, $35.31 to fillup
11/7


That's a little better although i'm still not happy with these numbers.
Title: Re: MPG, Part 2
Post by: DustyRusty on November 08, 2016, 10:49:13 PM
298.6 miles / 16.43 gallons =  18.17 mpg
$2.149 per gallon regular at Mobil, $35.31 to fillup
11/7


That's a little better although i'm still not happy with these numbers.

Oh, I think that's pretty durned good.  Best I ever got was 19+ mpg.  That was when the speed limit was 55 mph.  All good highway and interstate.  I always drove judiciously, proper tune up, and proper tire pressure.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 17, 2016, 07:18:25 AM
11/15
293.7 miles / 17.769 gallons = 16.52 mpg
$2.11 per gallon regular at shell, $37.65 to fillup


Not sure what is going on here.
Title: Re: MPG, Part 2
Post by: MrFiveOh on November 17, 2016, 11:09:26 AM
11/15
293.7 miles / 17.769 gallons = 16.52 mpg
$2.11 per gallon regular at shell, $37.65 to fillup


Not sure what is going on here.

Weather change? Causing different air fuel mixture possibly
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 17, 2016, 05:35:11 PM
11/15
293.7 miles / 17.769 gallons = 16.52 mpg
$2.11 per gallon regular at shell, $37.65 to fillup


Not sure what is going on here.

Weather change? Causing different air fuel mixture possibly

Could be.  Also, i notice when i fill up at Shell the mileage tends to differ more from average.   

Now, i will say this----that the carb that is on there now, while it runs great may not be optimally jetted for a 4.3;  Jeg's advertised it for 305's and 350's, so it may be a little rich.  i have not had time to get a 4.3 carb out of the junkyard and have it rebuilt.
Title: Re: MPG, Part 2
Post by: MrFiveOh on November 17, 2016, 05:36:14 PM
11/15
293.7 miles / 17.769 gallons = 16.52 mpg
$2.11 per gallon regular at shell, $37.65 to fillup


Not sure what is going on here.

Weather change? Causing different air fuel mixture possibly

Could be.  Also, i notice when i fill up at Shell the mileage tends to differ more from average.   

Now, i will say this----that the carb that is on there now, while it runs great may not be optimally jetted for a 4.3;  Jeg's advertised it for 305's and 350's, so it may be a little rich.  i have not had time to get a 4.3 carb out of the junkyard and have it rebuilt.
Just get a tuning kit is what i would do.

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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 19, 2016, 07:51:40 AM
Also, i'm pretty sure my converter is not locking up at any time.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 28, 2016, 08:16:49 PM
11/28
290.7 miles / 17.871 gallons = 16.27 mpg  :-[
$2.099 per gallon regular as Shell,  $37.51 to fillup.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 05, 2016, 07:02:13 PM
303.9 miles / 16.045 gallons = 18.94 mpg
$2.29 per gallon regular at Mobil, $36.89 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 12, 2016, 07:04:34 PM
258.9 miles / 16.613 gallons = 15.58 mpg  :(
$2.299 per gallon at mobil  $38.19 to fillup



i was having a little problem with the fast idle cam---it would not come down from low/mid step for some reason for about 2 days.  The choke, as far as i know however, did work ok.

Title: Re: MPG, Part 2
Post by: MannyDantyla on December 19, 2016, 11:45:10 AM
That's some good MPG!

I'm getting about 15mpg highway. I can't calculate overall though because my speedo and odometer are not callibrated to tire size. What I do is find a gas station (point A) and fill up the tank completely. I drive down the highway to where ever I'm going and find a gas station (point B) and fill up there. However much fuel I just added to the tank is exactly how much I used to drive from point A to point B. Then I use google maps to see how many miles it was from point A to point B. Then divide that number my the number of gallons of gas used.

I have a SWB K10 half ton. SBC 350 with 305 HO heads, sm465, 33" tires and 3.42 gears. Edelbrock 1400 carb (this is the 50-state legal, EGR, high MPG model for California). Long tube headers with true dual exhaust.

Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 21, 2016, 07:43:59 PM
12/21
297.6 miles / 18.1 gallons = 16.44 mpg 
$2.239 per gallon regular at Shell,  $40.53 to fillup


 :(

i am having a little issue with the high idle.  Also i think the Mr. gasket air cleaner #1487 is already clogged, but not totally sure.
Title: Re: MPG, Part 2
Post by: redhot1.4 on December 23, 2016, 03:14:27 AM
Man what's up the sad faces
An old school chevy pulling those kind mpgs. Is awsome,  I stop checking mine,, I stop trying to milk the old truck. And drive it like I stole it until I get me an overdrive

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Title: Re: MPG, Part 2
Post by: gunrac on December 23, 2016, 07:02:30 PM
HA HA 12 MPG....... Loaded or empty........always good 4 me......but it does work.....    85' 4x4 350.......
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 24, 2016, 09:15:11 PM
https://www.youtube.com/watch?v=bFcfhZrk-EA
Title: Re: MPG, Part 2
Post by: 79 Royal Sierra on December 30, 2016, 12:43:45 PM
U are better gas mileage then my 14 GMC Z71 with 6" lift and 35s. I think that is pretty good.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 31, 2016, 01:22:21 PM
NOTE:  Not accurate or official

313.8 miles / 17.095 gallons = 18.35 mpg
$2.259 per gallon regular at High's,  $38.62 to fillup

i don't think this is entirely accurate because my electronic speedo is acting up and actually went totally kaput today.   If anything i think the total miles should be higher.

i will have to fix the speedo or get a new one.

This is the Cyberdyne digital speedo/tach combo which worked well for the past 8 years and 20,000 miles.

i think it's best to put the mpg measurements on hold until then.
Title: Re: MPG, Part 2
Post by: Irish_Alley on December 31, 2016, 01:52:07 PM
use your phone and get a gps app
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on January 01, 2017, 05:27:57 PM
use your phone and get a gps app

How can we make this work without:

1) Having to remove/reinstall the phone each time i drive.  i can get a 2nd phone, provided it's not as expensive as getting a new gauge.

2) Having to turn the phone on and off each time i drive.  Is there a way to wire it in so that it will recharge?  Or can i use a car charger?  Will this draw on the battery when parked?

The cheapest GPS speedo i've seen is at least $300.  i'm not saying i won't go that way, but i don't WANT to.    Really i just need an accurate odometer.  i can go back to the stock odometer, but it's not as accurate as the digital speedo i've been using all this time.
Title: Re: MPG, Part 2
Post by: Irish_Alley on January 01, 2017, 08:54:08 PM
what what what? download the app on your phone. turn the app on while youre driving then close the app when youre stopped driving. if you want to reset the data you can at anytime.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on January 08, 2017, 06:40:03 PM
i know that a lot of times i'll ask for something, then turn it down.  But maybe we can all use this as a learning experience?

So what happened was i thought i would at least try to fix what was wrong with the gauge, if i possibly could, rather then to try/buy something new.

So in checking all the wires, the temp gauge wires, both ground and positive going to the gauge were loose.  The temp gauge was acting up too, but i didn't think it was a big deal since it would only be for a second or so when i applied the brakes ( i assumed it was because i was low on coolant and the coolant would surge forward and the gauge would momentarily go to zero since the sender would then not be touching the coolant.  But it turns out that was not the case).

i have all my gauges on the same ground circuit and power circuit.   So i tightened up all the wires and knock on wood, the tach/speedo gauge as well as the temp gauge have not acted funny since.


NOTE: Not accurate ( i think the gauge was missing around 90 miles this time)
286.1 miles / 17.193 gallons = 16.64 mpg
$2.399 per gallon regular at Wawa, $41.25 to fillup


Title: Re: MPG, Part 2
Post by: VileZambonie on January 08, 2017, 06:48:30 PM
Even though I never calculate fuel mileage, it is good to know that you are attempting to track yours and display the results. I am sure this info will help people in the future looking for data as well
Title: Re: MPG, Part 2
Post by: 1967KaiserM715 on January 09, 2017, 06:28:13 AM
I find it informative to keep track of fuel usage, I always use the trip meter between fill ups, and mark the cost of fuel. Had a fuel issue with my jeep once-temp switch went, so it remained on cold fuel circuit, seemed to run fine, but mileage went down, only like 2-3 miles too, and if I hadn't been writing it down I might not have noticed.

I like this thread, I find it cool to the steps run out and the results posted.


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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on January 12, 2017, 07:57:17 PM
291.7 miles / 17.520 gallons = 16.64 mpg
$2.299 per gallon regular at Shell,  $40.28 to fillup


The only thing i can come up with is that the air filter is clogged.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on January 20, 2017, 07:56:12 PM
298.8 miles / 16.79 gallons = 17.8 mpg

$2.299 per gallon regular at mobil,  $38.60 to fillup


We will notice something funny here----whenever i fill up at Shell i tend to get the best mpg.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on January 22, 2017, 05:14:42 PM
1/22 Sunday
309.6 miles / 16.99 gallons = 18.22 mpg
$2.299 per gallon regular at Mobil,  $39.06 to fillup


Took a long trip, thus more highway miles.

Title: Re: MPG, Part 2
Post by: Stewart G Griffin on February 13, 2017, 07:49:31 PM
2/13 monday
279.4 miles / 17.951 gallons = 15.56 mpg

$2.299 regular at shell, $41.27 to fill up.
Title: Re: MPG, Part 2
Post by: septantrionalis on February 14, 2017, 12:00:30 PM
Sure beats mine.  I have a 1974 Chevy K10.  3.73 gears.  35" tires.  4" lift.  350 engine.  NP203 t-case.  TH350 transmission.

Filled the gas tank to full.
Went 53 miles before having to fill up again.  Put in around 13 gallons.  Thats 4.38 MPG.

I need to try it again because this was going through mountain passes here in Colorado.
Title: MPG, Part 2
Post by: roundhouse on February 14, 2017, 09:29:44 PM
In the meantime, here is an interesting read concerning MPG, specifically regarding RPM:

http://www.oldsmobility.com/old/carlife_apr67.htm


2) i've noticed that the newer trucks, silverado tundra etc. have much larger cabs and are much taller than the squares.  So if a square was to get an LS it should produce wonderful mpg?
Swapping an LS into mine did not help the mpg

Felt like it Doubled the power of an old worn out engine though
An LS with a NV-3500 5 speed manual Trans is a real blast to drive
Even with 35" tires and 3.73 gears


We could never determine what engine we took out
305/327/350 ?
No casting numbers on it at all
Either a crate motor or more likely since the truck has a state issued VIN and no factory numbers on the frame or dash. It was a stolen recovery that had every number ground off at the chop  shop




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Title: Re: MPG, Part 2
Post by: redhot1.4 on February 15, 2017, 02:06:57 AM
That's crazy good mpgs for what it is. I had my wife's 2009 gmc acadia v6 3.6 2wd in the shop for a timing chain job plus new plugs and cv - axles and a full service, , finally I get to drive it for a long hual , 18.3mpg a little disappointed
It gained a whole 1 mpg lol.. nl

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Title: Re: MPG, Part 2
Post by: Captkaos on February 15, 2017, 07:53:23 AM
My LS swapped twin turbo truck gets 17mpg on the highway (with me not driving conservative, think PowerTour)  It gets about 13-14 city, again, I drive it aggressively some times.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 15, 2017, 08:55:49 PM
Tuesday 3/15:

305.8 miles / 17.329 gallons = 17.65 mpg

$2.259 per gallon regular at mobil  $39.15 to fillup
Title: Re: MPG, Part 2
Post by: roundhouse on March 20, 2017, 10:13:04 PM
I don't worry about mpg on any of my vehicles

You lose way way more money on depreciation than the fuel cost
 And since I almost allways get my vehicles for half price I figure I saved enough on the purchase price to pay for the fuel , even if it's 10 mpg

And square bodies are old enough that there is no depreciation , so worries there
I haven't noticed it with the pickups.  But the K-5 Blazers are rapidly gaining in value


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Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 22, 2017, 07:33:17 PM
I don't worry about mpg on any of my vehicles

You lose way way more money on depreciation than the fuel cost
 And since I almost allways get my vehicles for half price I figure I saved enough on the purchase price to pay for the fuel , even if it's 10 mpg

And square bodies are old enough that there is no depreciation , so worries there
I haven't noticed it with the pickups.  But the K-5 Blazers are rapidly gaining in value


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i was thinking about this the other day.  i don't do all that much driving, so the fuel savings between and 8 and a 6 cylinder really isn't that much.

i think the blazers are going up because it's a very durable vehicle that is easy to modify---no computers.  And if there is a computer like that later models and/or with TBI, it's easy to disable.   i'm thinking of getting one.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 22, 2017, 07:35:49 PM
Weds. 3/22
268.0 miles / 17.82 gallons = 15.03 mpg ????
$2.329 per gallon regular at Shell,  $41.50 to fill up.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on April 11, 2017, 08:46:04 PM
Tues 4/11

302.8 miles / 16.589 gallons = 18.25 mpg

$2.359 per gallon regular at Mobil,  $39.13 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on April 17, 2017, 08:16:29 PM
Mon 4/17

313 miles / 17.445 gallons = 17.94 mpg

$2.459 regular at shell,  $42.90 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on April 25, 2017, 07:27:03 PM
tue 4/25

304.4 miles / 15.981 gallons =  19.04 gallons   (more highway miles/less stop and go this time?)

$2.399 per gallon regular at Mobil, $38.34 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 06, 2017, 08:54:04 AM
Thur, 5/4

306.0 miles / 18.122 gallons = 16.88 mpg

$2.349 per gallon regular at Shell, $42.57 to fillup


The odometer may have been acting up though---total miles lower than actually.  Hopefully minor issue with speedo gauge.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 11, 2017, 11:13:21 PM
Thurs 5/11

311.6 miles / 17.517 gallons = 17.79 mpg

$2.299 per gallon regular at shell,  $40.27 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 18, 2017, 08:54:29 PM
Thurs 5/18

317.9 miles / 16.489 gallons = 19.27 mpg

$2.299 per gallon regular at mobil,  $37.72 to fillup


Much more sustained highway driving this time.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 24, 2017, 08:34:06 PM
Wed 5/24

316.8 miles / 16.97 gallons = 18.67 mpg

$2.359 per gallon regular at mobil, $40.03 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on June 03, 2017, 11:53:21 AM
Thurs  6/1

334.4 miles / 17.164 gallons = 19.48 mpg

$2.359 per gallon regular at Exxon,  $40.49 to fillup


More highway miles, and i think these figures are pretty close, but i think there is something going on with the gauge---either the gauge is going out or the speed sensor is going out.

So i will temporarily stop tracking mpg until the issue is resolved, but i'm too busy to mess with it now.

i still thing the figures are fairly accurate though.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on July 05, 2017, 09:09:16 PM
Wed. 7/5

350.8 miles / 18.226 gallons = 19.24 mpg

$2.139 per gallon regular at exxon,  $38.99 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on July 14, 2017, 08:15:11 PM
fri 7/14

325.6 miles / 17.879 gallons = 18.21 mpg

$2.199 per gallon regular at mobil, $39.32 to fillup



Oil change   19800
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 03, 2017, 07:37:20 PM
10/3

302.1 miles / 17.558 gallons = 17.21 mpg

$2.379 per gallon regular Sunoco,  $41.77 to fillup.
Title: Re: MPG, Part 2
Post by: Smitty31 on October 04, 2017, 10:40:23 AM
If it's a v6 shroud your looking for Stewart go to car-parts.com make sure to include dash inbetween car and parts. I found quite a few there for 25 or less. They will send you pics of it before you buy. They represent salvage yards all over the U.S. I paid 25 for the shroud and 25 to have it shipped. I had previously looked all over my area and the net for one with no luck. Also zieg85 has one on here.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 08, 2017, 03:38:16 PM
If it's a v6 shroud your looking for Stewart go to car-parts.com make sure to include dash inbetween car and parts. I found quite a few there for 25 or less. They will send you pics of it before you buy. They represent salvage yards all over the U.S. I paid 25 for the shroud and 25 to have it shipped. I had previously looked all over my area and the net for one with no luck. Also zieg85 has one on here.

i was in that boat, but decided to go with an electric fan.  Works great and there's more room underhood.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 10, 2017, 09:33:07 PM
314.5 miles / 16.934 gallons = 18.57 mpg

$2.31 per gallon regular Mobil,  $39.27 to fillup.
Title: Re: MPG, Part 2
Post by: Smitty31 on October 11, 2017, 04:41:54 PM
how do you get such great mileage ? I have a 4.3 v6 and the best i can get is 18 all interstate miles. driving back and forth to work which is mainly backroads i aveage about 13.5
Title: Re: MPG, Part 2
Post by: juggernaut6625 on October 11, 2017, 05:52:37 PM
This is a great thread. I have a 83 swb stepside w/ 350 w/ an edelbrock carb, 5x14 K&N filter, short headers, and true duel exhaust. I'm unsure of the diff or transmission. I am told the diff is original and the transmission is a stock replacement. My big goal is for my truck to be a daily driver and of course good on gas. I was told EFI was the only way to get over 13. Im currently getting 10-13. What are the major things to check and replace to get great MPG? Also do any of yall run ethanol free? Does it seem to help?
Title: Re: MPG, Part 2
Post by: Irish_Alley on October 18, 2017, 09:34:56 AM
the best and free mod you can do is on your right foot. keep speeds lower than 60 and ease into the gas when youre taking off. your trans could be a th400 or th350 (if auto) and you wont have OD with those just a 1:1 final gear. if you have to replace the trans due to it burning up is the only time it might be feasable to replace it. if you replace a good th400 with a 700r4 you will be spending too much money that you prob wont never recover in the saved MPGs unless you can get the trans, crossmember and driveshafts for free or cheap. axles may help but again its going to depend on what you have for a ratio

also take a look HERE (http://forum.73-87chevytrucks.com/smforum/index.php?topic=30546.0) to find out more about your ratio
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 22, 2017, 07:51:44 AM
how do you get such great mileage ? I have a 4.3 v6 and the best i can get is 18 all interstate miles. driving back and forth to work which is mainly backroads i aveage about 13.5

Sorry it took so long---was/am very busy.

i think one thing is i usually don't go above 65, although i will attest that the 4.3 has no problems going much faster than that :)

i think the 2.56 rear gear helps.  This is great for the highway, not so great for anything/everything else....
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on October 22, 2017, 08:00:26 AM
This is a great thread. I have a 83 swb stepside w/ 350 w/ an edelbrock carb, 5x14 K&N filter, short headers, and true duel exhaust. I'm unsure of the diff or transmission. I am told the diff is original and the transmission is a stock replacement. My big goal is for my truck to be a daily driver and of course good on gas. I was told EFI was the only way to get over 13. Im currently getting 10-13. What are the major things to check and replace to get great MPG? Also do any of yall run ethanol free? Does it seem to help?

i don't run ethanol free----can't find it.  We have, i think E10 and some stations have E15.  Going thru the thread, i noticed that i tend to get better mpg when i fill up at Shell.  But i don't think this is conclusive at this point.

i don't think running efi is the ONLY way to get over 13mpg, although it probably will help.   i don't know anything about Edelbrock carbs, but i run a quadrajet and i think it's a pretty good way to go, not just for mpg, but overall.

What are the specs on the engine?   Also, if you look at the SPID sticker, this can help determine what rear axle ratio you got.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 17, 2017, 08:59:00 PM
11/16
313.2 miles / 17.61 gallons = 17.79 mpg


Don't know exactly how much to fill up because they were too cheap to print a receipt (a different Shell), and i was in a hurry,  but around $41
Title: Re: MPG, Part 2
Post by: Irish_Alley on November 18, 2017, 07:50:35 AM
got your trans fixed?
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 19, 2017, 09:04:43 AM
Trans turned out to be ok.  i did do a fluid and filter change though.
Title: Re: MPG, Part 2
Post by: Irish_Alley on November 19, 2017, 09:41:36 AM
good deal. what was the issue? lack of fluid?
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 22, 2017, 04:38:10 PM
11/20

285.6 miles / 18.727 gallons =   15.25 mpg   ???

$2.359 per gallon regular mobil,  $44.18 to fillup.


????????
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 23, 2017, 07:52:55 AM
good deal. what was the issue? lack of fluid?

i noticed that i did not update my trans problem thread.  What happened was the water pump weep hole was leaking----all the way down onto the trans cooler line----which made me think the trans cooler line was leaking water (and of course water is NOT supposed to be in the trans----so i thought the trans was hosed).   As it turned out, i traced the leak back to the pump and replaced it with an Edlebrock 8811.  REALLY not happy with the Advance Auto budget line pump, which seemed to only last about 12,000-15,000 miles.  VERY happy with the Edlebrock.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=35709.msg301880#msg301880

Trans seems to work fine.

On a side note:
As i did some premature research on transmissionses, because i thought i would have to replace mine,  i heard that a 700r4 is the same length as a TH-350 with 9" tailshaft, and this appears to be true.  So, if most trucks came w/ 9"tailshafts, then it's a bolt in swap, although the trans crossmember has to be moved up 2", or modified, or maybe there is an aftermarket bolt-in crossmember..............because the 700's trans mount location is 2" further up than the TH-350's.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on November 28, 2017, 07:07:52 PM
11/28

305.9 miles / 18.435 gallons = 16.59 mpg  >:(    ?

$2.47 per gallon shell, $45.70 to fillup
Title: Re: MPG, Part 2
Post by: MrFiveOh on November 28, 2017, 10:48:37 PM
good deal. what was the issue? lack of fluid?

i noticed that i did not update my trans problem thread.  What happened was the water pump weep hole was leaking----all the way down onto the trans cooler line----which made me think the trans cooler line was leaking water (and of course water is NOT supposed to be in the trans----so i thought the trans was hosed).   As it turned out, i traced the leak back to the pump and replaced it with an Edlebrock 8811.  REALLY not happy with the Advance Auto budget line pump, which seemed to only last about 12,000-15,000 miles.  VERY happy with the Edlebrock.


http://forum.73-87chevytrucks.com/smforum/index.php?topic=35709.msg301880#msg301880

Trans seems to work fine.

On a side note:
As i did some premature research on transmissionses, because i thought i would have to replace mine,  i heard that a 700r4 is the same length as a TH-350 with 9" tailshaft, and this appears to be true.  So, if most trucks came w/ 9"tailshafts, then it's a bolt in swap, although the trans crossmember has to be moved up 2", or modified, or maybe there is an aftermarket bolt-in crossmember..............because the 700's trans mount location is 2" further up than the TH-350's.

You are correct about the 700r4 swap. If the existing TH350 had the 9 inch tailshaft (which was common for a TH350 in a truck) then all you have to do is move the crossmember back and drill new holes OR you can do like i did and put in a  aftermarket cross member ( from my friend as Tejas Steelworks (does LS swaps on our trucks) which cleaned it up and weighs alot les than factory)
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 05, 2017, 06:45:19 PM
12/5

301.0 miles / 16.201 gallons = 18.58 mpg

$2.399 per gallon regular at mobil, $38.87 to fillup.



Whenever i fillup at my regular shell, i tend to get better mpg?
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 13, 2017, 07:30:43 PM
Wed 12/13

270.8 miles / 16.716 gallons = 16.19 mpg   :-\

$2.399 per gallon regular at mobil,  $40.10 to fillup
Title: Re: MPG, Part 2
Post by: justin_jj_taylor on December 20, 2017, 06:40:20 AM
So you got worse mileage on the Mobil fuel or the Shell fuel? I'm currently working on a 1979 1 ton with a rebuilt 350 that has had issues for quite some time now, finally just discovered that there's water in the tank, which keeps causing issues in the carb. We believe the culprit is poor fuel. Regardless, there's really no other way that water could have got into the tank besides poor fuel quality, so I think your biggest opponent now is wherever is offering worse fuel!
Title: Re: MPG, Part 2
Post by: Irish_Alley on December 21, 2017, 07:41:31 PM
could you have a hole in the top of the take or the seal for the fuel pump assembly isnt intact or isnt in place
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 25, 2017, 02:06:08 PM
So you got worse mileage on the Mobil fuel or the Shell fuel? I'm currently working on a 1979 1 ton with a rebuilt 350 that has had issues for quite some time now, finally just discovered that there's water in the tank, which keeps causing issues in the carb. We believe the culprit is poor fuel. Regardless, there's really no other way that water could have got into the tank besides poor fuel quality, so I think your biggest opponent now is wherever is offering worse fuel!

According to the log, i tend to get better mpg with Shell.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 25, 2017, 02:08:13 PM
Fri 12/22

281.2 miles / 18.071 gallons =  15.56 mpg  :(

$2.429 per gallon regular at Mobil, $43.89 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on December 31, 2017, 09:42:13 PM
Sun 12/31

284.5 miles / 17.582 gallons = 16.18 mpg  :(

$2.499 regular at Mobil, $43.94 to fillup

Lame.
Title: Re: MPG, Part 2
Post by: juggernaut6625 on January 03, 2018, 06:03:37 AM
i don't run ethanol free----can't find it.  We have, i think E10 and some stations have E15.  Going thru the thread, i noticed that i tend to get better mpg when i fill up at Shell.  But i don't think this is conclusive at this point.

i don't think running efi is the ONLY way to get over 13mpg, although it probably will help.   i don't know anything about Edelbrock carbs, but i run a quadrajet and i think it's a pretty good way to go, not just for mpg, but overall.

What are the specs on the engine?   Also, if you look at the SPID sticker, this can help determine what rear axle ratio you got.
[/quote]

My SPID reads G01 rear axel - standard K34 Electronic speed con, LE9 5.0 liter v8 GAS, MX0 4-spd Auto Trans.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 01, 2018, 04:42:16 AM
Not sure if original poster has lost interest or not.  But interesting real world fuel mileage thread, both part1 and part2.  My experience from decades ago plus a few observations might be of interest on this topic. 

Way back decades ago I bought a 1971 Buick LeSabre with 31k miles and 350 Buick V8 (when GM divisions had own
 unique inhouse V8)  Had TH350 and 3.08 rear end.  This was pre-pollution era, points ignition, no overdrive or lockup converter.  Got 13mpg in town and 22mpg on long trip.  This is 4200 pound car.  The later pollution era version of this engine in similar weight car got 14mpg tops.  Buick 350 ended in 1980.

Moving forward I had a 73 C20.   350 Chevy V8, TH350 (not sure why it didnt have a TH400), and I really dont remember its axle ratio.  It got 8mpg.  I was not impressed.  Well until it threw a rod through side of the block, then less impressed.  Needing to get it back on road cheap as possible, I looked in shopper paper for something cheap to put in it to get it on the road.  Found a pre-pollution Buick 350 for $100.  Made some custom engine mounts and bolted it in.  Yes the top two bolts on Olds/Pontiac/Buick enginesI  were different from Chevy, but you can bolt it up to chevy transmission without them if you have to.  I  reused the big bore 2bbl carb from the Chevy engine.  Got it going.  This 5000 pound truck got 16mpg!   For anybody not familiar with 3/4 ton from this era, 16mpg is pretty darn good, amazing with a 350 and  3spd automatic.  Now this is 2wd. 

Now been thinking lot about this after past couple years battling a high mile 1994 Ranger with 4.0L V6 and manual transmission where at one point it was getting 9mpg.  Yea really.  I am old man and not big fan of computer engine controls.  But finally got it back to 12mpg city and 16mpg hiway.  The devil is always in the details and on computer engine, there are a LOT of details.  And yea the OHV 4.0L though very durable engine, truly not very good mileage despite all the computer stuff.  I find it ironic that a compact Ranger gets same mileage as that old C20 with the Buick engine and automatic, and not much better than my 6000 pound 4wd F250 with non-computer carb six.  Tell me again about progress we've made protecting the environment...  How again do we pollute less by burning more fuel?  Is EPA secretly run by Exxon?

But I digress.  Having thought lot about my experience with the Buick and C20 while suffering 9mpg with the Ranger,  and reading online about SBC fuel mileage.  Came to conclusion fuel mileage in carb V8 mostly revolves around camshaft profile and of course distributor advance curve.  This assumes you have an appropriate size carburetor that is tuned for that particular engine.  Most non factory carbs get way oversized and not jetted properly.  Same with huge exhausts people think they need that kill low end torque.  Seriously a fuel efficient vehicle probably only rarely go over 3000rpm, you dont want it set up for racing where you pump most gas/air through it for super high rpm race track speed.  Just makes it painful in traffic.

Now saying this from searching and reading various forums.  For stock carburetor SBC the best economy cam that gets mentioned again and again is the GM cam used on the pre-pollution 327 that they referred to as the 300hp cam.  Thats a cam that has 194/204 duration at 050 inch lift.  Lot clones of it, but best deal for SBC probably the Summit 1101.  When I actually got to searching amazing how popular this cam profile is on older flat tappet cam engines of all makes.  If you look enough you can find this profile cam for lot of old engines even the straight sixes.  Though availability fading away as those engines fade away.  The first generation SBC was just super popular so cheap parts continue for it... to certain extent. 

Now to curve a distributor without a machine made for this purpose is lot trial and error changing springs and such on centrifugal advance.  But the modern world does offer some interesting aftermarket shortcuts.  Not particularly cheap but interesting.  Where you have a magic box that you can hook to laptop and program the advance curve you want.  I can only say I have read about them not used one.  But if I were trying for best gas mileage, I think I might if I wasnt having any luck playing with springs and such. You lock down any centrifugal or vacuum advance and the magic box does the work.  There is a programmable MSD box for like $400 and some lot more expensive.  Ouch.  But found two cheaper.  This one is around $200:  http://www.cbperformance.com/product-p/2013.htm  And here is link to a thread where there is lot discussion.  https://www.thesamba.com/vw/forum/viewtopic.php?t=606203&postdays=0&postorder=asc&start=0
 Yea its by company specializing in VW stuff but its universal, can use it with any distributor engine except odd fire V6. 

The other is around $300:  https://www.retromotioninnovations.com/   This one seems to have lot better thought out software to program it and can connect directly to laptop with usb cable rather than having to use a serial to usb conversion cable.  Whether its worth the extra $100, have no idea.  Like say I dont have any personal experience with any of the magic boxes.  But if I am going to computerize, then being able to do my own tweaking rather than rely on big brother seems way to go.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 01, 2018, 05:13:04 AM
Oh yea, been reading about the 4.3L V6.  You can get that same profile cam for the TBI versions.   None for the Vortec with the balance shaft unless you can get one custom ground.

Oh, bit trivia I picked up, the 1990-91 Astro van seems to had best factory camshaft profile.  Though probably worthless info.  No idea why just those two years and just in the Astro.

I suspect you might get a C10 to top 20 with a carburetor V6, but probably only with five speed manual and right cam, etc.  I personally rather attempt it with 250-6.  People understimate the straight sixes they are not like a V8 or modern V6 or even OHC straight six.  There was an thread I think on the 67 to 72 Chevy pickup board.  Without changing anything else some guy put a progressive Weber 2bbl from Vega or Pinto or something on his straight six and got 19mpg.  Dont remember now if that was a 230 or the 250.  He of course had to rejet it.  But Weber is very tunable. 

I have owned three half ton Chevies from 60s.  The 1960 Apache 10 with 235-6 and granny four speed got 16mpg.  The 66 C10 with 230-6 got  about same.  The 67 C10 with 283-8 and three on the tree got around 15.  NOne of these were geared for economy.  They were farm trucks.   Put say 3.27 rear in the 1960 and probably got 20 just from that change alone.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 09, 2018, 07:02:24 PM
Haven't lost interest----i've had the truck parked for the last 4 months because i didn't want to drive it in the snow.   i will be switching back to it soon.


Thanks for the writeup.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 15, 2018, 05:00:22 AM
http://www.hotrodders.com/forum/67-camaro-327-rebuild-gas-mileage-help-137498-2.html

Having read heck of lot stuff on fuel mileage with carb engine, thread above contains some of best advice I think.   I do agree with their opinion that people overdo the gearing in the quest for bit extra fuel economy.  You might get bit more gas mileage, but you lose lot drivability.

Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 17, 2018, 01:09:32 PM
Truly annoying, keep thinking about what kind mileage I could get in full size pickup with non-computer carb engine mostly with cam I mentioned and one of the magic boxes for custom distributor advance.  And to do experiment on the cheap.  I dont want to spend lot money rebuilding lot stuff or buying crate engines or the like.  Thing is I dont drive enough anymore to need another vehicle or for fuel mileage to matter that much.  Long as fuel mileage is double digits (single digit fuel mileage truly sucks) then life goes on. 

But I get an idea in my head, really like to see if it works.  And not wanting some big body restoration basket case like most affordable antiques tend to be.  Newer half tons have gotten amazingly heavy too, up there similar to older 3/4 ton and usually long cabs and short boxes.  Maybe a Ranger/S10/Dakota, the 90s era compact trucks weigh nearly as much as the full size 60s and 70s  half ton trucks though alas none had 8 foot bed on them.  Least not that I know of.  Manufacturers didnt want them competing directly with their half ton full size trucks.

 Probably wont get this out of my system until I eventually do the experiment.   I know this is Chevy forum, but personally I am pretty well brand agnostic.  I have owned lot GM stuff over years mostly cause it was most available at best price in places I have lived.  Ford seems little cheaper where I live now, so I currently own Ford also I like manual transmission trucks and Ford trucks lot more likely to have a manual transmission.  GM new vehicle buyers truly loved their automatics from 70s on up. Though some here might be interested that when the light duty 5spd grenaded in my Ranger (stupid ford engineers put same dang 5spd they used with the four cylinder behind the 4.0L whereas the 5spd behind the 4.2L in full size was lot heavier duty), I replaced the grenaded five speed with a SM420 granny four speed out of an early 60s Chevy pickup since I already owned this transmission!  And I had the fun of adapting it.  Love mechanical puzzles. Those old granny four speeds were bullet proof, noisy, slow shifting, but bulletproof.  They were originally designed for medium duty trucks so overkill for pickups.  Way Ranger geared I never saw point in an overdrive anyway.  I rarely drive over 60mph.  Driving it now reminds me lot of my favorite old 1960 Chevy Apache 10.   All manufacturers made some good stuff and some that was better to forget.  I have current Ranger where its usable and reliable and check engine light stays off.  So rather not tear it apart to try different drive train.
Title: Re: MPG, Part 2
Post by: Irish_Alley on May 17, 2018, 01:48:19 PM
im sure gearing does play a role in the mpgs but power is also a factor. take my cummins that ive talked about before. with the 350 tbi i was getting 12mpgs now im getting 16 with the same setup behind it (4l80e and 4.10 ratio) in my 91 crew cab v3500. so i got a little over 30% better millage with a different engine that operates in a different rpm range. and the dodge was putting 3.55 behind their cummins for a better mpgs. now the sad part is if you regear or swap motors the price might not ever pay for itself. not sure how much is gained by the OD trans but it might help
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 18, 2018, 12:26:03 PM
I am not familiar with that 305-8 economy truck GM sold in 80s.  Mostly for marketing purposes I am sure and probably not a joy to own in real world.  But I am very familiar with similar 300-6 Ford super economy model also for marketing purposes.  Whatever else they did, Ford put in something like 2.21 gears, it was some insanely high economy ratio that pretty well made truck undrivable considering the power to weight and light duty manual 4spd overdrive.  But they advertised like 30mpg  EPA estimate.  Friend owned one of these.  Literally it would get real world mid 20s mpg which was about as good as the little 4cyl Japanese pickups of the time.  Yea with a carburetor. But just starting off on level ground required major struggle slipping the clutch.  Each and every time. Manual transmission doesnt have the help a torque converter gives an automatic with such high axle ratio. You could smell the clutch lining each and every time.  And unless you lived somewhere that all roads were flat it made you to truly want to avoid driving the thing let alone ever trying to carry a load with it.  Most people quickly decided to put more realistic rear axle gearing in it which promptly lowered fuel mileage to mid to high teens like most half ton pickups.  Or some put in a granny 4spd and started off in granny low.   Overdrive in such a vehicle was a joke.   

If you want overdrive IMHO, then you want something like 4.11 rear or something 3.xx numerically close to that.  Something that lets you start easily but then slows engine down at hiway speeds with overdrive engaged.  Thats whole idea of an overdrive or was traditionally until EPA rules made offering overdrive with 3.27 or higher gears somehow magical.  All it means is an overdrive you can never use in real world.

And yes, my point exactly about spending anything just for few more mpg.  You have to drive a lot miles to pay for it unless 1. you do all labor yourself and 2. parts are cheap, maybe from a you pull it type yard.  And truly makes you wonder about new half ton truck starting out around $30k and I bet most go out the dealer door at much higher price.  If you have that to spend on a vehicle that isnt earning an income, then fuel economy is least of your worries.  I cringe just thinking of the mortgage payments on such a truck.

Like that guy in hotrodders.com thread I gave link.  The one that rebuilt the 327 on his 63 Impala.  He regularly gets over 20mpg with 3.25 rear and M20 4spd (close ratio, not an overdrive).  He said yea there are benefits of fuel injection and overdrives, but you would have to drive lot miles to pay for small gain.  Obviously if he is regularly getting 20+mpg on a 4000 pound car, exactly how much would there be to be gained?  Now on the old Ford he mentions with the 292 Y-block, it has a 2-spd automatic.  He gets 16mpg city or hiway.  On that car no doubt changing transmission would be big benefit.  Those old 2spd automatics, Ford or GM were not terribly economic to drive and I always found them annoying to drive compared to a three speed automatic or manual.  They were meant as a super cheap automatic for the low end of the market I guess.  Personally never understood the attraction of an automatic at all, but most people seemed to love them.  My brain just automatically tells my foot to clutch and my hand to shift a manual without me thinking about it too much.  Is annoying switching vehicles with very different shift patterns.  Back in those days you could, for economy minded, buy a three speed manual with an overdrive.  You pulled out this knob on dash to engage overdrive.  Not that popular though.   Bit like that electric overdrive on 70s era Volvos, which had little switch on top of the shifter knob. That was lot nicer than pulling knob on dash.  I liked those old Volvos but never figured out why they didnt just have a slot for fifth gear in shift pattern.  They did eventually do that sometime in 80s I think.  But not so many people buying a manual transmission by that time.  You could afford a new Volvo, you wanted all the bells and whistles I guess.  Sad for those of us driving them at the end of their life when automatics truly suck cause they can go anytime and cost a fortune to replace.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 19, 2018, 12:17:41 PM
I apologize again for posting non-GM examples.  But this is a fuel mileage thread, and for me old OHV engines with carburetor vs high tech stuff computerized up the wazoo is more important comparison than Ford vs Chevy vs Dodge vs the world.  Like I said I have owned good and bad of several makes and am pretty brand agnostic.

Anyway this is interesting blog page of guy with a 1984 Crown Vic with 302, and running automatic without the overdrive hooked up. http://www.vinny.us/archives/298  He converted it from TBI cause of difficulty around parts for it due to age.  Anyway more important its a 3900 pound car with a 3.08 rear axle.  Sound familiar?  Apparently stock cam and an old Motorcraft/Autolite 2bbl carb off a '79 400-8 engine, which personally I think would run somewhat rich for a 302 but he didnt mention rejetting it. 

But he is getting 22mpg to 24mpg hiway after carb and Chinese aftermarket vacuum advance distributor.  I would say without knowing specs of  the stock cam and such, that this is pure lucky combination.  I had heard of some of the 80s Crown Vic and Lincolns getting pretty good hiway mileage.  But hotrodders seemed to hate these mild 302s, probably good reason to consider such for an economy vehicle.  Its just impossible to find accurate info on factory cam used in these.  You look at parts sellers and they just have generic stock cam that no doubt isnt what was actually stock in these and the generic hot cam they sell to the Mustang crowd.  You can however get a 194/204 at 050 aftermarket Schneider cam.  Or there is a Summit cam for these that is 204/204 at 050 which is close enough.

Ok, here is link to a third party test of the 1984 Crown Vic when it came out. https://www.cars.com/reviews/the-morning-call-and-mcallcoms-view-142068910676 The test car had the towing package with a 3.55 rear axle and got observed mileage of 12mpg in city and 19 on hiway.  So first link with the 3.08 axle sounds correct and not just bragging.  Makes me think this engine in 1984 had a cam much like I pointed out in the pre-pollution cars that got similar mileage.  Wish there was way to know cam specs in that 1984 Crown Vic.  I am just betting when Ford went to TBI, it controlled emissions enough they could use a more mileage efficient cam.  Here is key remark in the review: "rated 134 horsepower at 3,600 rpm and 232 foot pounds of torque at 1,600 rpm"  which says to me they were interested more in good fuel economy than some crazy high horsepower at some crazy high rpm for marketing purposes,  that nobody ever drives at on street.


I was looking at Ford V8s cause its way easier to find a good cheap low mile 302 than a Chevy 305.  Forget finding a cheap used low mile Chev 350.  That ship has sailed.  Ford 351W not nearly as common as the 302 either.  Ford pickup people really like them.  No idea why but the Ford and Chevy straight six engines also getting up there in price if they dont need total rebuild.  Probably just getting rare anymore. Now Chevy 4.3L are very common and pretty cheap even some low mile versions.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 19, 2018, 04:11:27 PM
Ok, sure these details all that useful to Chevy owners, but found out that apparently that 1984 Crown Vic 302 used a cam just slightly less than one I keep mentioning.  Oh and Summit sells a SEALED POWER CS1158R for 302 for $107 that is 194/204 at 050   That would be the bargain mileage cam for the flat tappet 302.  Only shown as mild performance cam for late 60s to early 70s Windsor engines.  Dont see it used in carb pollution engines or  the TBI or later computer engines.   Though that last 302 that was optional engine used in late 90s Exploders had a roller factory cam close to this.

I do have an old 83 Malibu fence row decoration out back with a 305.  Guy traded it to me in exchange for tuning up his ancient VW.  I dragged it home must be 15 years ago, never did anything except steal couple parts off it.  Never tried starting, knowing the guy, figured either engine seized or transmission shot.  Or perhaps it laid down a smoke screen for mosquitoes....  The other day did put a socket on the crank and wonder of wonders it still turned.  No idea if its still good enough to do a shade tree overhaul with new bearings/rings and lap the valves or not.  Not worth putting much money or time into it since I can get low mile Ford 302 or Chevy 4.3L for around $400 to $500.  Wait until I find a cheap rolling truck body/chassis that doesnt need body work, see what fits best in it.  Preferably a single cab long bed, but those in good shape getting rare.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 20, 2018, 06:03:43 PM
Not sure if i've already posted this, but read:

http://www.oldsmobility.com/old/carlife_apr67.htm


RPM is a big factor.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 21, 2018, 06:57:53 PM
Yes you did post that.   And it was interesting.  But on a pickup that is more truck than car, really cant see going higher than 3.2x  and probably more like 3.5x  rear.   Should be able to get pretty good mileage with 3.2x axle I think as maybe best compromise.   This being with non-overdrive transmission.  If I had an overdrive then I would something 3.7x to 4.11, somewhere in there.  I truly dont see point of an overdrive with a 3.2x rear axle  unless you are spending all your time driving high speeds on the interstate.   

Interesting looking Craigslist.   I found an 1985 C10 longbed in very nice condition, somebody had done body work and gave it new coat paint.  Very pretty. Also had 4spd transmission which is rare in 80s C10.  Said it didnt run, no other details.  Wanted $1200.  New tires.  Probably worth it if I was wanting a primary vehicle.  Very nice condition body for a 1985.  No doubt would most likely need an engine.  I mean seller be stupid not to put a little money into it and sell it in running condition if it was trivial problem, the body was that nice.

And found a 2000 F150 single cab long bed with blown engine.  $450 with solid body and paint still pretty good.  Thats a bargain if you are wanting something to stick a cheap engine into.  No emissions inspection in my state so not problem putting older engine/transmission in it.

But looking in my own back field there is my old 1976 Dodge D100 that I walk past most days and its just become part of the scenery.  I bought it cheap at auction back in 90s.  Drove it couple years until auto tranny started slipping.  Parked it where it sets.  so its set for 20 years.  Ugly but no rust to speak of.  I opened hood today and  could move crank pulley back and forth a bit, meaning take out plugs and put some ATF in the cylinders  and no doubt it would completely free up.  I had intended to put a 4spd in it but got busy with other things and it never happened.  Do have an old Dodge 4spd I got cheap at some farm auction for it, but never bought a bellhousing and flywheel, etc.  Anyway its still relatively solid old truck and I already own it so it would make ok vehicle to experiment with.  One neat thing about this generation Dodge pickup is that it has a rain gutter above the windshield and circling around above doors.  I have seen so many old Ford and Chevy trucks that the windshield seal at top leaks and water gets in and rusts inside the cab above the windshield.  Absolutely no rust above windshield on this old Dodge.  That alone made me smile and think this would be worthwhile project.

Anyway its still solid body.  No doubt need some tires that hold air and brakes gone through.  But be good test bed for testing carb fuel mileage.  Even if my state gets emission inspection, carb engine be no problem in it and its probably old enough they wouldnt even want to test it.

So interesting choices.  I should pull that Chevy 305 out of the Malibu and disassemble it to see its condition, as I have a Chevy 4spd and bellhousing and flywheel etc so be cheapest way to go.  I imagine however this 318 is in better shape even if parts bit more rare and costly.  And if neither engine is good, wouldnt offend me to put in a cheap low mile Ford 302 though I dont have a spare granny tranny for a Ford.

Oh I do remember when I was driving the Dodge before transmission started slipping, it never got better than 13mpg.  Course this is a pollution engine so sure a decent cam combined with manual transmission would get me into high teens.  People have said the pre-pollution 318 could get 20mpg.  I have just never seen one do that.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 23, 2018, 02:56:34 PM
I maybe sorry on the Dodge, well if I keep the 318.  The carb pickups with this engine just were not known for great gas mileage.  Dont think the later "Magnum" roller cam fuel injected versions that great mileage either.  My 13mpg was pretty well par for the course with the carb V8 pickups.  Course lot Chevy and Ford V8 of this era similar.  One in great condition and geared 2.71 could get 16mpg hiway.  Little more, maybe 18mpg with lean burn.  I remember lean burn era for Chryslers, thankfully dont have that mess.  No idea of my rear axle ratio until I get the truck pulled out of its grave and tires that hold air put on it.  Hopefully tag still on the axle.  I have feeling its going to either be 2.91 or 3.21.   Hoping for the 3.21.  From memory and how it drove, really doubt it was lower than that though.

Only cam changes anybody mentions is to hotrod an older A-body and great love of something called the purple cam from late 60s 340 version of the small block.  Dodge pickup people dont seem to change cams much.  Seems odd since cam change from pollution cam be one of cheapest improvements possible.  Only two places selling aftermarket 194/204 at 050 for it and they are expensive.  Cheapest would cost $200 to get one shipped and you have to then buy set new lifters on top of that.  The 204/214 at 050 lot more common and lot cheaper.  Summit sells generic package deal of this more aggressive cam plus lifters for $117 but it requires a set of expensive special aftermarket valve springs.  Which in my opinion means its a more aggressive cam than those promoting it want to admit.  A mileage cam should be able to use stock valve train.  How much difference exactly for fuel mileage???  From all I have read, I still think the 194/204 is the mileage sweet spot cam for most older OHV engines.  And possibly one could advance the cam timing with adjustable timing set might even things out with that somewhat hotter cam?  I believe advancing the cam timing 4 degrees lowers torque curve by 200rpm.

No mention of recurving the distributor either.  Think one of those magic black boxes to change timing curve on the fly with a laptop would be way to go.  Lot more control than playing with springs.  Though if doing it on fly, be better to have a friend manning the laptop while you are driving.

Oh ran across this article on historical gas mileage improvements of pickups over the years:  http://www.trucktrend.com/features/1602-truck-power-and-fuel-economy-through-the-years/  They dont seem to want to talk about huge price increases and great increase in complexity to achieve very meager improvement.  Nor the big weight gains.

I did find a $70 318 clutch bellhousing.  Would need flywheel and clutch kit whichever engine I went with.  But this was bargain for a 318 truck bellhousing that will bolt to the granny four speed.  Anymore lot those old bellhousings seem to be made of gold way they are priced.  Lot of them up around $200+.  Separate bellhousings seem to ended in 90s when manufacturers went to manual transmissions with bellhousing cast as part of the transmission.  Now separate bellhousing either ancient factory stuff or very expensive aftermarket.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 24, 2018, 11:33:57 AM
i think cylinder deactivation may have a lot to do with it.

On one hand, yes i think there has been a large improvement in pickup trucks in terms of mpg AND power;   i rented a 4x4 crewcab with a 5.3 and the thing DID get 19 mpg highway according to the computer, which i think are pretty accurate.   Now, i've also got 19mpg highway in my own truck, but it was with the 4.3---so less power and i was probably lighter.

On the other hand, i was able to get 17 highway with a 350, carb and conventional (old?) HEI ignition in that same truck.  Power could be comparable to the 5.3 with a few mods with no mpg penalty.

Now the new pickup is probably 800-1000 lbs heavier than mine, but is 2 mpg really an improvement IF the mpg gains are mostly from LS engine---less friction, fuel injection vs. carb (maybe a 10% improvement), Distributor-less ignition and cylinder de-activation?    In other words, put the new engine in a square and you get roughly the same mpg increase?

So, there have been improvements, but there kinda haven't?

Go ahead and get into the new 4 cyl that will be in next years silverado, YES a 4 cyl.  i don't have time to discuss.
 
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 25, 2018, 09:56:51 AM
I really dont understand why the fat half ton pickups.  Seems stupid for me.  Yea heavier vehicles if sprung correctly do ride better and theoretically could pull larger trailer without tail wagging the dog.  Its why luxury cars have traditionally been rather bloated.  I guess way they price new pickups now, that they are LUXURY vehicles cause only wealthy can truly afford them without a 30 year mortgage.

As to a four cylinder half ton.  Four cylinder engine was offered in 90s era second generation 2wd Ranger with extended cab that weighed around 3800 pound.  They discontinued offering four cylinder 4wd Ranger in the second generation because of the extra weight.   4wd extended cab Rangers weighed around 4200 pound!!!!!   So if you used an OHC 4cyl engine like that with a 5spd and you did gearing like 4.56 rear axle, then I think a four cylinder could push around an older full size truck in an acceptable way.  The 4.56 axle even with overdrive would limit speed, so gotta figure this wouldnt probably go over 65 comfortably.  You can even go to something like 5.71 axle but you would need an engine that could run comfortably at high rpm for that to work.  Europeans for decades used very small engines in cars we would consider too big for such, but they geared them low and made the engines turn high rpm.  One reason was that you payed higher tax for a larger engine in Europe.   American cars on other hand traditionally used big engines and high rear axle ratios.  They turned low rpm.

As engineer friend told me back in college, you can push around full size car with a 3hp lawn mower engine.  It would have to be geared so high that it would only move at literal snail speed, but it could do it.  200:1 ratio?

I vaguely remember somebody long ago mentioned in Popular Mechanics or Popular Science (think in 80s?) blue printed a Volvo 2.3L OHC engine and put it in a full size rear drive Caprice/Impala.  Anyway they made it drivable and it got a little better mileage than 6 or 8 offered.  Still four cylinder in a heavy car so no race car by any means, but usable, it could get up to hiway speeds of the time.  Think we still had 55mph limit?  Think they were trying to prove some point that vehicle manufacturers werent doing everything they could for fuel mileage.  And they were correct, except for fact GM simply couldnt sell a four cylinder full size car.  Its like current efforts to sell an electric car, few people want them especially at the price offered.  Time will tell if they can sell a four cylinder half ton pickup.

I guess you dont remember the earlier Cadillac 4-6-8 engines.  Sure it wasnt as sophisticated as current system but people went out of their way to disable it for drivability issues.  I think some arent pleased with this mandatory in current full size GM pickups???  Happens when car companies have to please EPA first/foremost and customers take what they can.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 25, 2018, 10:29:17 AM
Made me look, the early 70s Dodge D100 like mine weighed around 3800 pound best I can find searching on web.  Just not too interested in making it a 4cyl, though for sure it would be unique.  Hmmm, might be interesting, definitely unique....  That 3800 pound was with a V8, so it would be even less weight with a 4cyl.  Might indeed work, would definitely want something like 4.56 rear axle though.  I think those extended cab Rangers with 4cyl were kinda dogs to drive especially with an automatic.  Lot weight for a 4cyl.

You know one best four cylinders ever offered in heavier vehicle was that Mitsubishi 2.6L.  The weakness was all the nonsense added on like balance shaft and 12valve cylinder head (cracks).  But will say it moved those 80s mini vans  which were around 3500 pound around pretty well with carburetor and automatic transaxle.  I never drove one of the rear drive Mitsubishi pickups with that engine and manual transmission.  The simpler version of this engine (8 valve and no balance shaft) used in Mitsubishi/Dodge D50 pickups did last pretty well.  Still see a high mile version show on Craigslist once in a while.  Always a 5spd of course.  Lot of the 2.6L in the minivans died because of oiling problems caused by worn bearing in the balance shaft.  Lost oil pressure and then the complex timing chain setup went to omaha...  Smart people put in kit to eliminate the balance shaft when they rebuilt the engine.

There also was the MerCruiser 4 cylinder 3.0L (181).   It was a stroked Chevy Nova 153 engine from 60s.  Lot simpler than the Mitsubishi engine.  No experience with one in a car though.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 25, 2018, 02:07:26 PM
I kinda need to know condition of the 318 before I go farther.  Pulled plugs and none were oil fouled, but looks like it was running bit rich.  All were uniform thinly coated with black, neither fluffy nor oily. Hmm, could been wrong carburetor, one jetted bit rich.  Or automatic choke wasnt working quite right.  Pulled a valve cover and rockers clean, no sludge.   Actually just way it is, probably could start it up with bit work.  Just as it sets.  I did put some ATF in cylinders and turned engine over with socket on the crank bolt.  It didnt put up any fight, so was just bit stuck from setting 20 years, not rusted or anything.

I will play with it some more, then try to start it as it sets and then do compression test.  I think its still pretty good ole engine.  If I were sifting through a junkyard looking for cheap bargain core engine to use, this one would go home with me as a likely gamble.  Not thrilled that it will cost like $260 for cam and lifters I want.  But if I am going for mileage, thats a necessity to test my theory that bad mileage is mostly from pollution era cam.  Oh and it has two piece rear main seal.  Those are just painful to change out anytime.  Big plus for the Ford 302 same vintage that it used a one piece seal.

Trying to think back 20 years ago.   I know I took apart the 2bbl Carter carb just to get it home.  Some idiot designed the thing so one piece internally could be installed backwards and previous owner had done just that.  These were ok but not great carburetors. Reversed that and it ran ok.  Had to replace left front lower ball joint.  Thats about it.  The truly annoying thing is that the ignition modules kept burning out.  After couple long walks home I learned to carry a spare.  This was back before I knew you could just mount a GM four prong module to chunk aluminum and it would work fine with nearly any magnetic triggered pre-computer era distributor.  With GM module could use either standard coil or GM-HEI/Ford-TFI remote coil. And without a ballast resistor.  That four prong GM HEI module was very robust design and the better mouse trap.  Only thing it didnt like was heat.  So you wanted to mount it remotely on chunk aluminum preferably next to radiator by front grill and use the thermal grease mounting it to the aluminum.  I used them on Volvo, Ford, Nissan, and probably some others I've forgotten.  Never had one fail whether GM or a clone.
Title: Re: MPG, Part 2
Post by: Coasting2aStall on May 28, 2018, 03:58:42 AM
For anybody not familiar with old CJ jeeps, it was about as hard getting good fuel mileage out of them as a full size pickup.  Despite them being significantly lighter weight.

Anyway here is thread on Jeep forum about mileage of CJ with AMC 304-8. http://www.jeepforum.com/forum/f8/gas-mileage-amc-304-a-1296215/   Really interesting posts by "JeepHammer".  He goes on a bit soapbox style, but he does get how things work together as a system.  Some good info in his ..um speeches.  Tells how he gets 20-22 in his CJ with the 304.  Apparently he custom tunes jeeps for a living?

 I never owned an AMC 304 in anything, but did have couple of the 1970s era full size Wagoneers (one was a 2door Cherokee Chief) with FULL TIME 4wd and AMC 360 and TH400.  I actually really liked them.  One got 14mpg and other got 16mpg, amazing mileage with full time 4wd, quadratrac I think they called it.  Yep from the late 70s so pollution era. 

Another bit interesting info on my 318.  Seems Chrysler used a "203/203 at 050" cam in their bigger 360.  Same LA block so using this stock 2bbl 360 cam in the 318 is a cheap upgrade.  I can get this cam and set lifters new for under $100.  Its a single pattern cam but I dont think be worth the extra $100 to get my preferred  aftermarket "194/204 at 050" cam.  Just really cant see there being that much difference.

I swear researching fuel mileage for carburetor V8s is quite the challenge.  So many conflicting views and lot liars.  No one single magic bullet, thats for sure.  I would love to break the 20mpg barrier, but mostly just want to prove to myself I can get better mileage out of a carb V8 pickup than the 16mpg hiway I get with my fuel injected Ranger.... without making it unpleasant to drive.   Even 16mpg isnt bad in a full size V8 pickup, so thats enough of a goal for the Dodge, to at very least match that and hopefully beat it.  Only ran across one guy claiming to regularly hit 20mpg in stock  Dodge  pickup with carb 318.  He had a manual 3spd.  Unfortunately didnt give any more details.  I'd of said he was exaggerating if he had automatic, but if stars were all aligned when his truck was put together or he has very good mechanic that can tune it within a gnats eyelash of perfect, then suppose its possible.  That egg taped to bottom of his right shoe probably helps too....

Getting into hot summer weather so not sure how much progress on Dodge over summer, but no hurry.  The Dodge is more curious hobby than a necessity.   Least like to get it to point it can start and move under its own power around the yard. 
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 08, 2020, 09:07:23 PM
Part 3:

i decided to rent a truck for a while---since i'm still working on the trans in the usual truck as you may know.

'20 Ram 2500 crew cab with 6.7 cummins diesel, single rear wheels
Not sure what trans, but automatic
Not sure what rear, but i would imagine 4.10?

438.5 miles/21.00 gallons = 20.88 mpg    Computer said around 20.3, but i think it's averaging everything, not just last tank?
$2.699 per gallon diesel at mobil,  $56.69 to fillup   i did not fill up all the way because i was returning the truck.    Also, i drove more than 438 miles, but i was only measuring mpg for the last tank.

i'm pretty impressed with the mpg considering the size of the truck which i feel is TOO BIG----i usually have to take up 2 spaces.

If you're not picky about brands, this is a nice truck.  Very quiet.  i did tow a little and it did good.

Of course, i only buy gm generally.  But if i wasn't brand loyal, yes i would buy one.
Title: Re: MPG, Part 2
Post by: Irish_Alley on March 08, 2020, 09:19:14 PM
for the longest time the cummins was paired with 3.55 ratio. i think a few years ago it did change to 3.73
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 09, 2020, 07:01:25 PM
Well whatever rear end ratio it had, it's a pretty impressive drivetrain----IF you can afford it all.

i've not driven a duramax or powerstoke yet, but i imagine  they are on par with the cummins?
Title: Re: MPG, Part 2
Post by: fitz on March 11, 2020, 06:48:25 AM
  I had the privilege of driving a 2019 F250 powerstroke / 4 door / 8'bed truck for 4 months last summer / fall (the truck on the right).  In 4 months I put 15k on it.  The dash computer says it averaged 18.6 mpg's.
  It was an Enterprise Rental courtesy of Ford while they processed the paperwork to buy back my 2019 F250 under the lemon law (the truck on the left).  My truck had the 6.2 gas motor and averaged 14.4 mpg's for the 2,800 miles I owned it.
  I enjoyed driving the diesel,  but I think maintenance would be expensive as the truck gets older.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 11, 2020, 05:52:55 PM
Yes, i rented from Enterprise as well.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 18, 2020, 09:36:39 PM
Part 4:


i've joined the LS club:

'11 colorado crew cab
5.3 LS (LH9)
4L60 trans (which, i think, is a renamed 700R4?)
4.10 rear, but still rpms decently on highway----1900-2000 @70mph  because of OD.
Not sure what the front diff is.

339.6 miles / 16.16 gallons = 21.01 mpg
$2.439 per gallon regular  Exxon   $39.42 to fillup.

i'm not giving up on the square at all.  i'm just very busy these days and don't really have time to really mess with it as the primary transportation----it was down over one month because of the trans.   Plus, i felt i needed another car anyways.
Title: Re: MPG, Part 2
Post by: Irish_Alley on March 19, 2020, 07:50:34 AM
be cautious of the AFM on those causing collapsed lifters. from what i understand its not a matter of "if" but "when", its somewhat of a easy fix and you might be able to luck out and prevent it from happening. theres a few youtube vids on it
https://www.youtube.com/watch?v=pP7I5tbXsfw

you can even disable it. that whole thing about dropping to 4 cylinders sounds good but imo isnt practical. also you might notice your battery volts dropping to 12.8 or so and this is normal and GMs attempt to save some millage
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 20, 2020, 09:14:23 PM
i don't think the LH9 5.3 has any of that "AFM" stuff.   It does have variable valve timing and flex fuel capability.   i need to brush up on my LS knowledge.  i've been very busy lately. 

i hear AFM/Displacement on demand isn't good for the engine long-term.  All these tricks to try to get mpg don't seem to pay off in the long run?    The turbo 4 in the silverado can't tow as well as the 4.3, 5.3 etc.    i will  try to locate the article concerning DOD not being good for the engine long-term.

Diesel seems to work great for towing, but then there's the high-initial cost which may never pay for itself unless you do a ton of driving.

You can't change the laws of physics.......
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on March 28, 2020, 02:36:53 PM
Still on the colorado

271 miles / 16.25 gallons = 16.68

OH NO.......

$2.599 per GALLOn regular at exxon,  $42.24 to fillup.

Now, i was late one day for work, so i was kind of hammering it and maybe that affected it.  Side note at 75 it still rpms below 2500rpm.
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on April 04, 2020, 06:22:35 PM
colorado

317.5 /  16.63 gallons =  19.02 mpg

$2.099 per gallon regular at exxon.   $34.91 to fillup
Title: Re: MPG, Part 2
Post by: Stewart G Griffin on May 15, 2020, 06:34:08 PM
colorado

329.7 miles / 18.067 gallons = 18.24 mpg

$1.859 per gallon regular at exxon,   $33.59 to fillup


i was late one day for work.  i think the colorado is speed limited to  99/100 mph?   i can't confirm this.

i discovered that the 5.3 LS DOES have some top end.
Title: Re: MPG, Part 2
Post by: fitz on May 21, 2020, 08:48:04 AM
With the long weekend coming up have you considered dropping the 4.3 in the Colorado and checking the mpg's?. Ha ha, how are you enjoying the Colorado so far?