Fuel mileage and overall cost of burning E85

Alky V6

Let's go racing, boyz!
Jul 29, 2001
12,802
84
48
Santee, CA
www.drwtransmission.com
I don't know about the rest of the country, but in San Diego, I'm noticing a move away from E85. The fuel is getting harder to source, and the few racers at the track that have tried it have been switching away from E85. It reminds me of a high school fad.
 

Turbo6inKY

Short Guy
Jun 18, 2001
1,434
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Louisville, KY
blog.andrewdscott.com
so...

i've got a low compression engine and i'm considering an upgrade to e85. Anyone out there convert an almost totaly stock car? if i were to upgrade total fuel system(pump,lines,injectors,conversion kit, everything) what am i looking at $??

oh ya- and stroking it out a bit
I converted mine. Only bolt-ons I had were a THDP, 2.5" ATR exhaust, a pump hot-wire kit, and an accufab regulator. Stock injectors and stock turbo. I could run 8.4 @ 83mph in the 1/8 all day long on 100 octane race gas (2.0 60' on regular all-weather radials).

I bought the injector + chip combo and a Walbro 340 from TurboTweak for about $500 all in, installed it in about two hours (including replacing all the rubber lines back at the tank with new stuff), and then ran 8.3 @ 84 mph on E85. That's about as apples-to-apples as it can get, and it turned out to be just as fast in the 1/8, but the fuel costs less than half as much (E85 is $3.45/gallon today, VP 100 is ~$7/gal here). I did not upgrade the fuel lines, and I'm having no trouble with fuel pressure creep from the Walbro overpowering the return line.

I run it most of the time now. My car pings on the pump premium they sell now. It didn't do that a few years ago. I switched to the E85 mostly to get rid of the pinging and prevent a blowup. I'll swap chips and run a tank of gasoline through it every now and then to try and rehydrate the rubber bits. Don't know if that actually helps or not, but it's worth a shot.

I'm seeing 13-15mpg in town, depending on how heavy my foot is. On pump gas I'd get 17-18mpg, again, mostly in-town driving.

As has been said before, E85 makes no sense compared to normal gasoline. The gas mileage hit isn't made up by the cost reduction. But compared to race fuel, it's a clear winner.
 

fast86gn

Texas Moderator
Staff member
Sep 28, 2001
3,207
355
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Garland,Texas
www.lspbc.org
Just thought I would add my 2 cents :) Interesting topic. I run E85 on my 98GS and get about 11-12 mpg. I don't drive it everyday so it's not to bad. Not many stations around here carry it, you have to find a Kroger that has pumps. The closet station is 8 miles away from my home so I don't let it get to low. It is $3.15 per gallon in this area versus $4.00 for 93 octane.

My son had converted this car over when he owned it. I don't think I would convert the GN, I would rather go the alky route. For now it's just 112 octane and keep in kill mode. Most of my street driving is back and forth to the track anyway. :) 6-7 gallons at the track gives me plenty for the street.
 

jiho2

Sporadic Poster
Apr 4, 2004
391
15
18
Redding, CA greater metro
it sounds like you would have to go to 16:1 - 18:1 compression to get better mileage
I wonder at what point the compression is so high, that enough more heat is being generated, that the cooling advantage from the ethanol is lost and it becomes a zero-sum game.

(I might add that a stock Hot Air motor does not reach the "equivalent" of 16:1.)
 

2swoosh

aka BURNRBR
Mar 9, 2006
196
11
18
119
South NJ border of Philly
I converted my GTR to Pro-Efi and can run on pump gas or e-85 i don't take it to work but drive it as much as weather permtting plus track time gas mileage is maybe 17-19 mpg combined i guess it's ok since C-16 is around $14.50 a gallon! in Atco Raceway here in NJ.. With e85 @ $3.69 per gallon is like heaven for my tune without fear of detonation so far she had gone 10.60s @ 134 with 1.7+ 60' on e-85 with the same street tune. I'm hoping the corn husk will stay for a while.
 

Turbo6inKY

Short Guy
Jun 18, 2001
1,434
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Louisville, KY
blog.andrewdscott.com
I just took a ~220 mile round trip from Louisville to Bloomington with the E85 and tracked the mileage.

15.4mpg in mostly 45-65mph country road driving.

I also tracked the mileage over a few days of in-city driving and got 11.8mpg.

This is with 60lb injectors and a TurboTweak 5.7 chip. So there it is.

The same vehicle recently did 20.8mpg on gasoline over a 300mile tank that included a run down to Bowling Green and back at 70+mph on I-65.
 

NEARING

Active Member
Apr 9, 2002
1,458
2
38
Schertz, Tx./ Smithland, Ky.
E85= Performance….How much? I have read several threads about the performance gains but no numbers. Does anyone have dyno results before and after?
Not a buick but my Zo6 picked up about 95hp and 50ftlbs at the wheels. E85 vs 110 both at 17psi on a dyno jet. Previous owner converted it to E85. I haven't picked up a copy of EFI live yet so I don't know how much timing it's running.

Makes me want to convert my Typhoon to E85

I got a tad over 17mpg (highway) on a 700 mile road trip last month. Around town it's CRAP!
 

XLR8ONU

Member
Nov 28, 2011
90
17
8
Arizona
I will make you all feel good about your mileage. Over the last 15 gallons of gas I pulled 7.6 mpg:)

I will admit that is with probably 15-20 all out pulls including 4 passes at the track.

I put a full tank in it for this week and going to try to play nice.

But none of this matters when you get to put down 25lbs of boost with out race gas cost or alcohol every day on the street!

Posted from the TurboBuick.Com mobile app
 
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larry33kc

Well-Known Member
Aug 19, 2001
1,504
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Latrhop MO.
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As far as the question about difference in performance with E85 VS gas. It's easy to figure. How many pounds of boost can you run(without) alky? 15-16 #'s somewhat safely? E85 you can safely run 27-29#'s. That's what about 150-200 HP Gain +\- depending on setup. That's cheap HP

That's a hugh difference. Now as far as mileage goes. I was getting around 9 at first which shocked me I have played with the tuned a little and got it to 14.5 and there might be a little more room left. But I switch to E85 because it is cheaper than race gas which I can't afoard and I can turn it up to 28#'s and not have to worry about it. I do have alky on the car but it is off unless I can't get E85 for some reason then I would turn it on.
 

TT/Ameasap

The White Blur
Jan 31, 2002
4,786
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I'm figuring out my tuning this spring with MPG's because I'm getting around 10mpg. I can watch the gauge move with my eyeballs.
Spark plug gap probably has an effect on it too.
 

696

Active Member
Jun 11, 2009
798
28
28
Southern IN
With a TT Chip set at 11.2 a/f for 1 & 2 then 10.8 for 3 & 4, I babied it for a full tank..13.2 mpg

Posted from the TurboBuick.Com mobile app
 

TT/Ameasap

The White Blur
Jan 31, 2002
4,786
435
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696,Those are WOT AFR's
Next time this weather decides to warm up again, I will be targeting 13.5 idle 16.5-17.0 cruise
I need to Loosen my plug gap to .030 ( I have a volt booster now)..That should net a lot better fuel economy for cruise.
 

MNwe4

Member
Sep 29, 2008
428
7
18
Minneapolis, MN
Glad to see I'm in the same boat as everyone else. Last year I was always around 13 mpg tooling around town, jumping on it every now and then. Haven't done an all hwy trip on it yet.
 

belsie

Active Member
May 16, 2011
785
28
28
Central Fl.
Throw the MPG out of this, is the HP and piece of mind worth the switch? Assuming fuel at the door and the differences in mods and equipment maintenance & personal tolerance, what is the concensus? Each has + and - but one has to be favorable???
Opinions are important while preferences make the choice..........:banghead:
 

TT/Ameasap

The White Blur
Jan 31, 2002
4,786
435
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I just got done burning another 1/4 tank today and it goes fast. Switching to E85 adds to the ''pain in the rear'' list for getting fuel all the time for me. I was always a pump gas alky guy and never worried about something so insignificant as getting fuel.
When your pumping 2.80 race gas in the car, it does make you giggle a little tho. I like the smell of E85 vs gasoline too. MPG has been the biggest drawback for me... I guess its just annoying.
 

XLR8ONU

Member
Nov 28, 2011
90
17
8
Arizona
So if you street drive everyday probably not the best as it is difficult to find some places and it goes quick. I don't care about MPG cause I'm hauling ass anyway and loving it. With that, You can't beat not putting race gas in the car and running 26 lbs on the street. I got so sick of worrying what gas was in the car and or paying for expensive race fuel, it was worth the switch. Today I pulled 13 mpg but I have seen 7 mpg as well over a 50 mile stretch. Just depends on how far you shove your foot through the floor board.
 

belsie

Active Member
May 16, 2011
785
28
28
Central Fl.
As I consider the switch to e-85 I wonder if mixing w/ gas for mileage when planning to just cruise on a longer trip. Obviously discipline on the pedal would be crucial (maybe turn boost down for the calm driving) but safer while possibly better mpg? Seems like extra work but worth it to prevent damage or........?
Any thoughts..................
 
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