Originally Posted by Stohlen
Well that depends on a lot of things. Ethanol tends to degrade fuel systems that were not built to handle it. The plastics and rubber lines and such break down over time, and the more ethanol you use, the quicker it happens. You can of course, replace the lines and pump with ones that can handle the fuel, but if you don't it will take several years of use before you run into any problems.
Now when you just add ethanol into the system, you are really not getting the benefit of the ethanol without tuning specifically for that ethanol content. Most people here add 30-40% ethanol and never touch the tune. Sure you may gain a little horsepower within the adjustability of the ECU, but the car still thinks you are running 91-93 octane and will not push the car for the 98 octane fuel it now has. So on an 100% E85 car, you're gonna want to get a tune specifically for E85.
I believe the injectors in this vehicle will flow enough to allow for the use of E85 only, but as you add more and more boost, upgrade the turbos, etc. you may run out of injector, which would of course mean you'd need larger, or more likely supplementary injectors to meet your needs. I don't see this being a problem unless you start going over 18psi or thereabouts, but I don't know that for sure.
Some true points here, but a lot of false info as well.
You cannot run 100% e85 on your stock light pressure fuel pump, you will throw codes because the pump will not be able to sustain the amount of flow needed.
Our injectors don't need to be changed at all, since we are DI our injectors are rated to some ridiculous flow rate, so don't worry about not being able to flow enough fuel through them because that is not a problem at all, regardless if you're at 20psi on 100% e85 like I am. Shiv is running e85 on the single turbo cars that are making 600+ whp
As far as the fuel system goes, still up for debate whether our lines are being effected and deteriorating from the fuel, some users on e90 post have been running e85 for over a year with at least 30k miles, and have had zero issues at all with their car. Time will tell, but for now, it doesn't look to be as damaging as everyone likes to believe it is.
If you want to run 100% e85, you will need an upgraded lpfp, Vishnu will be selling one pretty soon, and if you're into DIY's, there is a DIY on e90post for a e85 walbro pump that terry from bms is using in his car.
AFAIK, Vishnu is the only company supporting 100% e85 cars. They offer a flex fuel sensor that detects the ethanol content directly from your fuel lines, it plugs into the procede and adjusts the tune accordingly for maximum hp based on the ethanol percentage the sensor is reading. Since you are using the jb4, like people said above, I would aim for a 30% mix first and try that out on map 5. E85 is fun
Oh and one last key thing to remember is you will need a flash for new fueling tables if you plan on running more than 50%, if you do not have a flash, your fuel trims will max out at 34%. So it is recommended you raise the fuel ceiling with the flash
Just remember your gas mileage will decrease.