I just bought a COBB accessport off of our old pal Ridesober. He left his protune on there which I'm planning to use. The only problem is that his tune was for 93 octane. In my area, we've got mostly 90-91 octane, but we do have a few stations with e85. If I mixed equal parts of 100% gasoline @ 90 octane + E85 (according to wiki has about 96-97 octane) would I pretty much have 93 octane ?

 

You'll never get the mix anywhere near close enough to know it's mixed properly. Then on top of not being able to do that, you'll have to factor in the fact that no E85 station sells E85 exactly. One could be E73 or E79 one day, and the next be E70 to E83. You'll never be able to do that. Then, even on top of those two, you need to take in account that E85 needs more to equal gasoline. It's too confusing for me to go into, especially since you won't do it (if you're smart). Get a tune for 90-91 or upgrade the injectors (not sure what else has to be done for an evo) and get an E85 tune. Choose one or the other.

 

Ohh, and e85 in actual E85 form, is 108octane.

 

no

 

 

not true. its true octane rating is difficult to determine because of the conditions required for the r+m testing which requires an intake charge temp not possible with e85 due to its low boiling point and cooling properties.

 

Where is my face palm emoticon???

Anyway, go get a tune for 91 or w.e.. you are one crazy dude.

+ palm... this will have to do.

 

You might be able able to increase the octane but you would need your tune adjusted to work with a higher ethanol content. Mixing won't make 93 octane petrol, which is what your car is tuned for.

 

Alright, the reason why I asked this question is because I found folks that were mixing race fuel with pump fuel to achieve higher octane levels. So now I know, mixing E85 and pump fuel isn't a good idea for a tune based on 93 octane.

 

Yeah, race fuel is still a petrol as opposed to e85 which is an ethanol blend.

You could get 90/91 octane and use an octane booster additive. You'd have to do it for every fill though.

 

^ that and/or mix correct parts of 91 and race gas to get you to 93 ( I would shoot for 94 to be on the safe side though incase your calculations could be a hair off etc )

 

no..... double no..... fail! there would be serious consequences for putting e85 in ur car set up for gasoline..... e85 is 85% ethonal. not regular gasoline

 

Can anyone shed any light on how a water/methanol system works? According to AEM's description on MAPs website, "it's like having 100 octane for the price of premium."

 

Meth is like constantly mixing, pouring, and storing a ticking time bomb into the trunk of your car only to get a hair more power than you would if you just ran straight e85.

My recommendation is to just find a tuner nearby who can tune on the AP and have them install a larger fuel pump and injectors into your car and then tune for straight e85 since it is obviously available in your area. This would net you the most / safest amount of power on the car for your buck.

 

I agree with Chitown as well. Run E85. Mixing and calculating for octane numbers or running meth are dangerous games to play, too many variables. Look at my avatar. I knew I put that up for a reason...