Author Topic: MPG, Part 2  (Read 22819 times)

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #75 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.

Offline Smitty31

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Re: MPG, Part 2
« Reply #76 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
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Offline juggernaut6625

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Re: MPG, Part 2
« Reply #77 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?

Offline Irish_Alley

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Re: MPG, Part 2
« Reply #78 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 to find out more about your ratio
« Last Edit: October 18, 2017, 09:43:21 AM by Irish_Alley »
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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #79 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....

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #80 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.

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #81 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

Offline Irish_Alley

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Re: MPG, Part 2
« Reply #82 on: November 18, 2017, 07:50:35 AM »
got your trans fixed?
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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #83 on: November 19, 2017, 09:04:43 AM »
Trans turned out to be ok.  i did do a fluid and filter change though.

Offline Irish_Alley

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Re: MPG, Part 2
« Reply #84 on: November 19, 2017, 09:41:36 AM »
good deal. what was the issue? lack of fluid?
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #85 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.


????????

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #86 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.
« Last Edit: November 23, 2017, 07:57:06 AM by Stewart G Griffin »

Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #87 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

Offline MrFiveOh

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Re: MPG, Part 2
« Reply #88 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)
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Offline Stewart G Griffin

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Re: MPG, Part 2
« Reply #89 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?