E85 VS straight higher octane

[FromRagsToS4]

With ethanol being potentially dangerous if mixed improperly and/or not having the right fueling system for higher E mixes, Im curious to see what you guys' experiences have been with using E85 mixes compared to just straight higher octane fuel. Any performance improvement over ethanol-containing fuel compared to ethanol free? Do our cars (assume stage 2 or higher) like E85 mixes, or are they happier on straight 100 octane gas?

There's only 1 spot where I live that has E85, so I was wondering if it would be better to just buy a case of octane boost (https://boostane.com) instead of having to stock up on E85 fuel containers in the garage.

[jachien]

There are plenty of people that are mixing E85 with various fuels available throughout the country. I currently run full tank of E85 with an off the shelf flash from EPL. Where I live, there is a decent amount of E85 stations nearby to make it convenient for me to use E85. However, due to this car being my DD and living in so cal, sometimes a trip to Vegas is in order and there arent any E85 stations along the way. So from EPL, I wanted both the pump fuel flash files and the E85 flash files.

If you plan on running full tank of E85, an upgrade to the HPFP is in order (which is just a plunger replacement.. costs like $400?) in order to handle increased E85 fuel flow demands. Aside from a sputtering issue (unrelated to E85) I have no complaints running full tank of E85. Actually, about a week ago, I filled up with E85 and about 3 gals of 100 octane gas and the car felt really good. No quantifiable data for that other than seat of pants feel though.

I'm against buying a case of octane booster as i feel octane booster is more expensive than what its worth. I would rather just buy a gallon of toulene or xylene, however california has banned these chemicals from being sold at home depot anymore.

Try not to confuse octane with energy content though... Water technically has infinite octane... however we all know water is not a good fuel...

[onlyaudis]

all of those boosters tend to foul the O2 sensors and spark plugs over time with a nasty orange film. better for old pre cat hotrods than modern cars.

[bhvrdr]

all of those boosters tend to foul the O2 sensors and spark plugs over time with a nasty orange film. better for old pre cat hotrods than modern cars.

all of them that actually work that is ;) MMT will cause some residue. I havent heard of it causing any issues though other than being able to see the color of it and Audi probably denying a warranty claim on a car that has pistons that look like the additive was used. That would be a big deal i guess.

Mike

[onlyaudis]

MMT can also eventually settle out of solution and leave residue build up in the tank, fuel filters,, etc. I know boostane claims they fixed that problem, but how can you be sure? I sometime use boost additives on a couple of pre cat era high compression cars I own, but would hesitate to use it on a modern Audi. its E85 for me. Boostane is also now like $30 a can!

[bhvrdr]

wowzer that is a lot. How little of e85 can you run to make a difference? Such as getting you up to 96 octane or so from 93 (or to 94 octane from your 91)? I have one e85 station now within 15 miles or so and was thinking about filling up a 5 gallon. I dont want to deal with a bunch of gumming up issues that the e85 folks run into either though. hmmm

[SDBolts]

Heh, 100 octane runs like $8 per gallon for one.

If you really want to get crazy and don't want to use E85, tryToluene mixed with a little Marvel Mystery Oil to help protect the fuel system from being eaten. Be prepared to say goodbye to your cats though - but if you're really wanting to maximize power this way, why run cats? Besides, shooting fire out the tailpipes on downshifts/off throttle is cool.

Seriously, I wouldn't recommend that, although I did run a mixture of 100 octane + 4 gallons of Toluene in my WRX for track days only along with a catless downpipe. We do have S4's, not WRX's, Supras or similar, so we're obviously interested in a little more refinement and while having a flameshooter S4 might be cool for a day or so, I doubt that many of us want to do it on a daily driving basis...

[RichardCranium]

Just making sure I'm understanding this - is the question about blending 91/93 with E85 for use on a stock, untuned car?

[whiped]

A single gallon of E85 in a mostly full tank picked up 30-40whp on a local S4. It is APR Stage II, I believe on the 93 oct map. (We only get 92 at the pump in OR, I think he was pulling timing before adding in the E85)

This was done right in front of us on a dyno doing back to back pulls.

I have one E85 station ~20 miles from my house, I fill up 4 5gal cans. That usually last me about a month blending E30 fuel.

===================================

More so than anything else, I think people run E85 because it is cheap and more easily available than high octane fuel.

[onlyaudis]

plenty of threads on the e85 mix thing. 3 gallons or so at a fill up from near empty is an awesome octane boost, especially for those of us stuck with awful California 91 "premium" I noticed a big difference even still running my 91 stage 1 tune. not confident I can always get E85, especially on some road trips, so i have been hesitant to upgrade to a real 93 tune.

I never tried it when i was stock, but heard it even made a difference for people with no tune, especially on hot days.

[FromRagsToS4]

The question stems from me only having access to crappy 91 octane here in Idaho. I ran 3 gal of E85 and it felt great! I just want to make sure this isn't going to slowly be corroding my fuel system if done repeatedly, and if I can just "Boostane" my way up to higher octane a couple ounces at a time so I can run cooler and with more advanced timing, I would probably want to go that route. The price of the Boostane doesn't concern me.

Would the higher octane with either Boostane or mixing in E85 both have the same detrimental effect on my cats?

[whiped]

I don't think E85 will do anything to your cats, it might build up some gunk on your injectors though.

[LittleDozer]

I don't think E85 will do anything to your cats, it might build up some gunk on your injectors though.

Seems some of the GIAC guys have fouled their cats, my bet would be from mixing too much E85 on a tune not meant for it. Lean = burned up cats.

[FromRagsToS4]

And so if there is gunk on the injectors, is there a cleaner you can run through the system, or does it require manually taking them out and cleaning them? Also, the gunk buildup happens after a few fill ups, a few months, a year?

[LittleDozer]

wowzer that is a lot. How little of e85 can you run to make a difference? Such as getting you up to 96 octane or so from 93 (or to 94 octane from your 91)? I have one e85 station now within 15 miles or so and was thinking about filling up a 5 gallon. I dont want to deal with a bunch of gumming up issues that the e85 folks run into either though. hmmm

Highly doubt you'd see gumming with adding 3-5 gallons per tank. I've been running straight E85 for 7 months. Had gumming once due to a bad batch of fuel. Otherwise I just run an ethanol stabilizer every few tanks and have yet to see an issue again.

[whiped]

Seems some of the GIAC guys have fouled their cats, my bet would be from mixing too much E85 on a tune not meant for it. Lean = burned up cats.

Sweet! That means I should hopefully blow mine out soon. Restrictive bastards

If they blow out clean like a few of the guys have I won't even bother replacing them anytime soon.

I've ran injector cleaner through my car a few times just to be safe, not sure if it is needed but figured why not.

[bhvrdr]

Highly doubt you'd see gumming with adding 3-5 gallons per tank. I've been running straight E85 for 7 months. Had gumming once due to a bad batch of fuel. Otherwise I just run an ethanol stabilizer every few tanks and have yet to see an issue again.

Can anyone say if this stuff is any good to use...

http://lucasoil.com/products/fuel-tr...th-stabilizers

[LittleDozer]

Can anyone say if this stuff is any good to use...

http://lucasoil.com/products/fuel-tr...th-stabilizers

This has worked well for me https://www.amazon.com/Star-Tron-Enz...nol+stabilizer

[bhvrdr]

thanks man!

[db12]

Hmm now you got me thinking about adding a couple gallons for track days....just curious how that would work with my tune? From a different thread, APR supposedly builds in the E85 tune with 91 or 93 programs for the A4's that are flex fuel vehicles. Wonder if that applies to any of their tunes...

[tmoe]

here's what I use, has a nice way to meter 1oz doses needed for every 5 gals of my e85/93 mix.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[troyerco]

I run 4 gallons of E85 and fill the rest of the tank up with 91 here in Southern Cali.
I was running APR Stage 1 like this and the car felt noticeably stronger. A few months ago I went ahead and flashed to the APR Stage 1 93 tune on the recommendation of the dealer and it's even better.

One time I accidentally put in too much E85 (6 gallons) and that threw a lean code after awhile. I just added more 91 back in ASAP and all was fine.

[cspcrx]

You also need to know what the actual ethanol content of the E85 your getting is. My local E85 station is actually 51% ethanol (E51). I always fill up at about the same point, the last white line on the fuel gauge. I put in 8 gal of 91 and 5 gal of E85(actually E51) and run the 93 APR stage II tune. Car loves it and has never had an issue. I did this when the car was stock as well without any issues for almost 2 years now.

[FromRagsToS4]

Any recommendations for an ethanol testing kit?

[mjr034]

First time i tried E85 blending..
Ran 3 Gallons of E85 from the shell station last night with the rest 93 oct.

Running APR stage 2 (93 map) - car felt like it was pulling much harder. Noticeable enough to eliminate skepticism for me.. even on a 93 map the mix felt much faster.

[jimrobbington]

Hasn't @Loe proven several times that he gets better performance all around on E85 mix than actual high octane fuel?

OP, I ran 3 gallons of E85 in a full tank of 91 on stock car and noticed a nice improvement. Same mix on 034 stage 1 is much more impressive. These cars really enjoy the stuff.

Sent from my SM-G930VC using Tapatalk

[cspcrx]

Any recommendations for an ethanol testing kit?

This one because it goes lower than others I have seen.
http://www.fuel-it.biz/ethanol-content-tester/

[tmoe]

Hasn't @Loe proven several times that he gets better performance all around on E85 mix than actual high octane fuel?

OP, I ran 3 gallons of E85 in a full tank of 91 on stock car and noticed a nice improvement. Same mix on 034 stage 1 is much more impressive. These cars really enjoy the stuff.

Sent from my SM-G930VC using Tapatalk

E85 blend with shell 93 to (e25) did a better job of reducing timing pull than a 50:50 mix shell 93:sunoco 260gt and way way cheaper. Seems like the high IAT 3.0 really likes drinking alcohol!

[jayferzahir]

Has anyone done 3 gallon of 100 oct and the rest 91?


Sent from my iPhone using Audizine

[FromRagsToS4]

It's probably good performance, but will lack the cooling element of the E85 mix, so it will heat soak faster.

[4Rings3Liters]

Has anyone done 3 gallon of 100 oct and the rest 91?


Sent from my iPhone using Audizine

Why would you mix 100 octane with 91? You can run straight 100 octane as long as its unleaded with no issues.

[db12]

Why would you mix 100 octane with 91? You can run straight 100 octane as long as its unleaded with no issues.

guessing due to the cost....

[jimrobbington]

Has anyone done 3 gallon of 100 oct and the rest 91?


Sent from my iPhone using Audizine

E85 is typically 100-105 octane ish, and costs like 1/4 the price of race fuel. Last time I bought race fuel several years back it was over $7 a gallon here in Denver. E85 is cheaper than 91 octane fuel

Sent from my SM-G930VC using Tapatalk

[jayferzahir]

guessing due to the cost....

Yes it's $9 a gallon here in LA


Sent from my iPhone using Audizine