Anyone using E85

[clay69camaro]

I have a Subaru STI and on the forums for those cars there are some people turning out really high hp numbers by switching over to E85.

They also get larger fuel pumps, and really big injectors. Then with the right tune they crank out more hp with less boost, and if they turn the boost up they really crank out more hp.

I myself will be doing it with my STI. on 91+methanol I made 374awhp, but with E85 I'm hoping to hit mid 400's!

I was wondering if that was also a common trend among the classic cars? I haven't seen much of it on here.

[Flash68]

I am considering it and have been closely watching the list of E85 stations in Northern California... it has saturated my area decently but not quite enough for me to convert. I would really like to do this... 105 octane for $3.30 a gallon sounds nice right now.

[64duece]

Yep...been running it about a year or so on a twin turbo 570" bbc. Honestly, I haven't really pushed the tune to take advantage of it (more timing or boost). It's reasonably priced and offers up plenty of "head room" for saftey sake if vs pump gas. We run non-intercooled although have water/meth injection so...advantage goes to the cooler air charge affects aswell.

[clay69camaro]

Nice, Are there still benefits to running E85 on a naturally aspirated build?

[Flash68]

Originally Posted by clay69camaro

Nice, Are there still benefits to running E85 on a naturally aspirated build?

Absolutely. It's really 2 parts of analysis in my mind... one is the octane benefit (105 vs 91 for us in Calif). But then it does consume more fuel apples to apples compared to pump gas, but I don't know about you... I would not care if my MPG went from the current 10 down to 7 or 8. I'll take the ability to tune for more power based on the 105 octane rating.

[skatinjay27]

isn't that 105 rating not a minimum like regular fuels numbers are?

[clay69camaro]

Good point Flash, Thanks for your input.

Don't know what part of Norcal you are in but there are a lot more E85 stations up there than down here. I'm in Orange County, and there are no stations close by

[Flash68]

Originally Posted by skatinjay27

isn't that 105 rating not a minimum like regular fuels numbers are?

From my research you definitely have to be careful of what exactly you are buying and where you are buying the E85. It can vary but 105 octane is attainable from what I've read -- like anything, buyer beware, and you have to do your research. I've seen you can get as low as 95-96 octane and as high as 105. You can also buy in drums if you'd like, which is what my buddy back in South Dakota does with his converted race car. He pays like $2/gallon and gained 3 tenths in his 10 second drag car - no other changes.

[wmhjr]

105 octane is a very common myth for E85. E85/Ethanol is not 105 Octane. it is actually using 93-95 octane. Any quotes of 105 octane are based on an "interpretive" method of labeling octane based on the blending ratio of E85 - and NOT an actual octane measurement. It behaves differently, allowing a cooler fuel burn which sometimes results in similar effects such as you would get with high octane gasoline, but it is not 105 octane. If you're running wideband, it also requires a far far richer A/F ratio than gasoline. Almost 50% richer. General guidelines for gasoline are around 14:1. E85 is around 9:1.

By itself running E85 does not make more power. It actually makes less. You can sometimes however increase compression, etc with ethanol/alcohol to make more power. Typically that involves boost.

A recent engine builder shootout using E85 to build the highest power output naturally aspirated engines resulted in those engines producing less power than similar gas engines.

[TurboNova]

That is funny and exactly opposite to what we have found here on the dyno. On one test we switched from C12 to E85 from the station across the street and found 25hp with no changes to the timing. I love the stuff because the jetting is more stable, when you find peak power and add more fuel it usually does not drop in power for several jet sizes then if you set the engine up to run at the middle of the jet spread it will not be effected by outside temp as gas is.

For me there is no down side for E85, it is a no brainer. You did touch on A/F for E85 and gas but are off on the numbers a little.

Air/Fuel Ratio Gasoline E85
Stoichiometric 14.7:1 9.7:1
Max power 12.5:1 6.9:1
Max poower 13.2:1 8.4:1

Most A/F gages also read in Lambda and that is the scale you should be using either anything other than Gas.