On a quest for better MPG's (E85)

TT/Ameasap

The White Blur
OK, I am getting horrible fuel mileage ever since the switch to E85 and I am determined to do something about it. Here are the things I am going to try within the next couple days to help this car from being so thirsty.

1. Set lean cruise to 16-17 AFR
2. Regap plugs from .023 to .028 ( stock ignition system...But volt booster should help)
3. Maybe play with idle from 13.5 to 14.5
4. heck I have already lightened the car up a couple hundred pounds.
Anyone with a success story please chime in with details.
 

StageII86

Member
Kinda think it just comes with the territory. If you can lean it out some great, it may help improve your average on longer trips. But as soon as you begin to engage in any varied throttle conditions or get anywhere near boost It'll be guzzling it again.

Years ago I ran one of mine on c16 all the time and tried to help the mpg out some. Had near stalling at steady state cruise and as lean as I could get 83's to idle. Having the stock sender/analog gauge plus filling it up out of drums made it too hard to quantify the gains. I know it helped some though.
 

TT/Ameasap

The White Blur
Ya, but I went from around 16-17mph around town on 93/alky to around 8-9mpg. I think a lot has to do with the tune. I leaned out idle to 14.2 and it still responds great, so I will leave it there. Next is lean cruise.
 

we4Mateo

Double you eee what?
30% lower energy coefficient coupled with a low compression motor and there is simply only so much that can be done. Some E85 guys are getting ready for power tour and having these same discussions.
 
stoich is 30% lower and price is typically also around 30% lower , should be a wash but it will use more gallons anyway you slice it .

dollars of fuel per mile its competitive and performance per mile is where e85 should shine over pump premium and race fuel.

e85 can take more timing and or more compression to narrow the gap in normally aspirated platforms , but forced induction I guess you need to decide how to balance boost/compression/timing/fuel used
 

TT/Ameasap

The White Blur
Im already aware of everything you guys are talking about. I am just adjusting my tune/plug gap and seeing how much I can improve the MPG's. It is not right at all at the moment. I can literally watch the fuel gauge move every 10 miles or so. Im fully capable of doing this myself, but It would be nice to help someone searching in the archives and show how to optimize a tune for MPG's.
 

Ttype6

Well-Known Member
The most effective way to increase mileage with E85 is to mix it with 93. E85 uses 30% more fuel than gasoline ans there's nothing you can do to change that. See what the car will do on a 50/50 mix and work from there.
 

TT/Ameasap

The White Blur
Im not going to start blending fuels. Im gonna do all the things I listed and go from there. It is what is it after that. Im still on winter blend too.
 

BEATAV8

The Engine Whisperer
You should be able to get 13 or 14 mpg just by leaning it out a bit, assuming you are running rich now during light throttle as it sounds like maybe you are.

I haven't obsessed over it on my Buicks but I gander they are in the 12-14 range. With my SD car being the worse one and the MAF car being better.

My 2014 Silverado has been averaging 19.2 on E85 over a 600 mile mix of city/highway. It does 20.6 mpg with 87.
 

larry33kc

Well-Known Member
I went from 9.9 when I first started using it which shocked me to 15.8 after leaning it out and bumping timing.
 

TT/Ameasap

The White Blur
After doing most of the stuff mentioned, I am a LOT better now. I dont know what the MPG's are as of now, but it is much better.
 

BEATAV8

The Engine Whisperer
I checked mine yesterday since your post had me curious. 200mi/13.5gal = 14.8mpg (Maf car)

A little better than I thought, but the wife has been driving it to work all week and she's a pussy foot
 

CGASTON

Well-Known Member
You should be able to get 13 or 14 mpg just by leaning it out a bit, assuming you are running rich now during light throttle as it sounds like maybe you are.

I haven't obsessed over it on my Buicks but I gander they are in the 12-14 range. With my SD car being the worse one and the MAF car being better.

My 2014 Silverado has been averaging 19.2 on E85 over a 600 mile mix of city/highway. It does 20.6 mpg with 87.
Because the Siler a do has variable valve timing and compression around 11:1.

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turbonut85

Rarely used member
Just long hauled the power tour...(3200 miles in one week) on nothing but e85. Average mpg was around 16.5mpg. Saw as little as 14, and as high as 19. Just stating what I saw. Running 120s and a TT chip. Single walbro 340 on a stock long block with a TA61. Cruise AFR was 14.7-15.0 not much boosting while driving, but there was some for sure (all but impossible to keep the foot out of it...lol) car also pulled 390hp at the wheels and 410 ft-lbs on the dyno in Bettendorf. :)
 
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