Author Topic: MPG, Part 2  (Read 25971 times)

Offline Stewart G Griffin

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MPG, Part 2
« 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.

Offline Irish_Alley

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Re: MPG, Part 2
« Reply #1 on: August 27, 2016, 01:13:16 PM »
do you have a fan on it this time?
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #2 on: August 27, 2016, 05:40:09 PM »
Yes, definitely----a 14" Spal electric.
« Last Edit: August 28, 2016, 04:28:07 PM by Stewart G Griffin »

Offline redhot1.4

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Re: MPG, Part 2
« Reply #3 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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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #4 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

Sent from my SAMSUNG-SM-G870A using Tapatalk

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.
« Last Edit: September 22, 2016, 08:41:32 PM by Stewart G Griffin »

Offline redhot1.4

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Re: MPG, Part 2
« Reply #5 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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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #6 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

Sent from my SAMSUNG-SM-G870A using Tapatalk

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.

Offline redhot1.4

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Re: MPG, Part 2
« Reply #7 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

Sent from my SAMSUNG-SM-G870A using Tapatalk

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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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #8 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.

« Last Edit: September 13, 2016, 08:01:50 PM by Stewart G Griffin »

Offline zieg85

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Re: MPG, Part 2
« Reply #9 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
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline zieg85

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Re: MPG, Part 2
« Reply #10 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
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline LTZ C20

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Re: MPG, Part 2
« Reply #11 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.
LTZ Cheyenne C20

Offline zieg85

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Re: MPG, Part 2
« Reply #12 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
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline LTZ C20

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Re: MPG, Part 2
« Reply #13 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.
LTZ Cheyenne C20

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #14 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.