I've followed several threads on several boards that seems to indicate that E85 increases the hp/tq and performance of a turbo charged engine. Some tuners (e.g. Cobb) are also offering E85 tunes. Can E85 be mixed at the pump with 93 octane and if it can what is the percentage? And, will this cause any damage?

 

Ethanol have different properties of combustion, the mix is tricky... I use E85 in my Alpha 10 GTR but the tune is for 100% E85, I always empty my tank with gas if I want to put my E85 tune

 

Found the answer, no it can't.

Use of gasoline in an engine with a high enough compression ratio to use E85 efficiently would likely result in catastrophic failure due to engine detonation, as the octane rating of gasoline is not high enough to withstand the greater compression ratios in use in an engine specifically designed to run on E85. Using E85 in a gasoline engine has the drawback of achieving lower fuel economy, as more fuel is needed per unit air (http://en.wikipedia.org/wiki/Stoichiometry) to run the engine in comparison with gasoline. The additional ethanol required for a stoichiometric fuel ratio helps compensate for lack of energy provided by ethanol's lower heating value (LHV), which is lower than the LHV of gasoline.


Fuel systems and engines not designed or modified to use E85 may experience increased wear and may fail prematurely. Some (particularly older) fuel systems and those used in powersports and agricultural engines contain rubber seal elements which have excellent gasoline resistance but poor ethanol resistance. These systems generally can accept up to E10 without major degradation in service life of susceptible seal components

 

I mixed 50-50 in my 335 for two years, you need a tune or an ecu that can compensate for the lower energy content of E85, and also raise boost and timing to enjoy the available power.

 

you absolutely can not !!!... if you have an e85 tune... if you dilute 9 gallons of e85 with 1 gallon of 93 octane, then you have E75 , 2 gallons, E60 (im doing the math off the top of my head, but you get the idea).
this is why a flex fuel sensor is great... unfortunately we cant do flex fuel sensors on the OEM ecu, but Anthony has it on his switzer standalone syvecs

 

Also note that while a lot of people are running E-85 in the Turbos, the chemical make-up of E-85 has corrosive effects on many of the materials in the make-up of our cars. Many of the rubber and plastic compounds do not hold up to the alchohol, and especially aluminum.

I have seen some pretty convincing information on this....

Then there will be a host of people that will jump on my post and say it is harmless, etc., etc.....I am willing to wait and see the effects that will be coming over time....I personally am not willing to try, but to each his own.

Good luck with your efforts...Just a caveat here to help. If I find a good concise source of info I can post in one spot, I will do so.

DC

 

You need a tune for the fuel you run, and a fuel system that can deal with the ethanol content. But the 997tt seems to run well on E85 and there is tunes for 100% E85, so why mix?

The only reason N54 bmw owners mix is due to the hpfp being the bottleneck and cant support 100% E85.

I thinj Cobb even have a E30 ots map for N54's.