Have a buddy of mine who run's a High Mix of E-85, he said that he runs 50-50 with 93 octane and that he feels the difference after about 20 miles or so.
Doesn't he need a tune for this too work? Wouldn't the E-85 corrode the fuel system and potentially lead the car to produce more heat due to the lean mix?
I mean Ive been inside his car and it definitely pulls on 3rd harder than mine, note he does have a 19% pulley, Alta intake, and it is Straight piped with 2.5 inch piping all the way with no resonators or cats. His is an 05 JCW just like mine but with more miles too 112k Vs. 147k. I was wondering if anyone else on here has ran E-85 Mixed or straight without a tune?

 

Personally I wouldn't do this, esp without having AFR and Injector Duty Cycle data.

 

Thanks for you input, Yes I agree but I'm definitely interested in doing this the right way. Curious to what it would take in regard to MOD's and Parts needed to achieve 100% e-85 safely

 

E85 has less energy per gallon.

Gasoline has approx. 114,000 BTUs per gallon. E85 has around 82,000 BTUs per gallon.

Additionally the stoichiometric ratio of alcohol is much less than the stoichiometric ratio of gasoline. 9.8:1 vs. 14.7:1.

What the above means in a short version is the engine will need considerably more E85 fuel to travel a given distance at the same speed compared to gasoline.

Thus the fuel system must be capable of delivering this or the engine will not run right, could run lean, and this can spell trouble.

The fuel pump, fuel lines, injectors all need to be capable of the additional fuel load they'll have to deal with.

The stock system might suffice but it probably is on the ragged edge.

There is another problem. The amount of ethanol in E85 can vary. Thus you need, the engine controller needs, a way to know the percentage of ethanol in the fuel so it can properly fuel the engine. In some cases this is done with a special sensor in the fuel tank. In other cases the engine controller -- with the proper software -- can I believe deduce the percentage by the O2 sensor readings.

E85 can pose a problem for cars used in extreme cold. The 15% of gasoline helps in this regard but there's a limit.

If you want to run E85 or some combination of ethanol and gasoline other than the more common (and supported by the car makers) E10 (which my info is fuel distributors stay a few points under "10" so the fuel is really E7 or E8) you probably should look into an aftermarket system that has all the hardware and "tune" necessary to ensure proper operation running something above E10.

Then all you need do is know where you can buy E85 cause you're going to be burning a lot it.

 

I agree with RockC, but I want to add some more information.
It has not only a different stoichiometric ratio, but the flame is also slower, it means you will need more ignition advance. The E85 also has a lack of additive to lubricate the mechanics (fuel pomp, injectors...), it is preferable to add some in you fuel every 20k miles. I have seen few case of R53 running in 100% E85 without ECU tuning, it always end bad.

I made it on my R53 MCS before the winter, give it to a professional, he made a really good work. Mine is nearly stock (K&N air filter + JCW exhaust), but now with 100% E85 it has 210PS (175PS before E85).
Great improve on the really low rpm too. Fuel consumption rise to 10-15% in normal daily drive. In winter, the 15% gasoline are not enough, I add 20% and it start as easy as with full gasoline.

 

That's why it pulls harder...not because he's mixing E-85 in his fuel. Unless you get the car tuned to run on straight E-85 (lots more fuel, and more timing), it's pretty dangerous to start mixing E-85 and Gasoline without doing anything to your tune. You are better off to just run a good 91 or 93 octane gasoline.

 

I don't see how it wouldn't....you would be running super lean....a great way to melt a piston. Sometimes people do some pretty stupid stuff.....it never ceases to amaze me.

 

anything over 135 is pulling timing and reducing power, run torque and log your IAT. If doing mountain runs, autocross or HPDE it's gonna require menthanol to keep from reducing timing just no way around it with these top mounts.

Highway or around town no need for meth