Thread: E85 tune why? How?

advantages: ~104 octane (depends on mix available, changes), burns cooler (property of ethanol), cleans everything out, most of the time cheaper than gasoline.

disadvantes: fuel economy drop (have to use ~30% more fuel), need to find stations where it's available.


there isn't much to it, really.

Octane info: http://www.modularfords.com/threads/...-Octane-of-E85

I am going to be thread thief, but Adam D is also working on some of the same things I am considering, he just posted a WTB 1.9 rockers.

I'm running a 3.4 pulley w/ intake, pulley, AL104s, 180* tstat and working on a tune. I know it's January and things will change some when it warms up outside. I've got a buddy helping me with the tune and right now I've cut timing to 12* and am still seeing 2* of KR on 91 octane, can't find 93 around here.

So, buddy and I are discussing ways to get rid of that KR. He is trying to push me to buy injectors and run E85; I don't really want to run E85 due to being limited as to where I can buy fuel. I am considering looking for 1.9 rockers and going that direction instead; buddy says rockers basically reduce boost slightly there by allowing me to run more timing knock free.

Any thoughts ladies and gentlemen?

you need headers ^^

****! I have headers also. That's what happens when you post in a thread while having a conversation.

What's your afr?

You can run a lot smaller pulley on e85 than 93

Originally Posted by dsmuts

What's your afr?

I don't recall the numbers off the top of my head, but I know we went rich before pulling timing.

Originally Posted by Adam D

So this is not my intentions but does this mean hypothetically i could run a smaller pulley with less supporting mods to back it up? What is needed to run e85 tune and injectors

Depends on how far you want to go; but short answer yes. The advantages bio talks about all fight knock quite a bit. To run E85 you'll need bigger injectors so you don't run lean and depending on how small you're planning on going a bigger fuel pump.

If your still running a m90 most likely you don't need a bigger fuel pump yet, even on e85. If your pulling timing below stock to run a smaller pulley you need to run a bigger pulley. E85 rocks, drops egts a lot and has atleast 104 octane. Smaller pulley and more timing and all that's needed is bigger injectors and some tuning.

My afr was 11.3.

A few years ago, my 01 had a 3.4 pulley, intake, and 3" catless DP. We have pretty ****ty fuel here in this part of Nebraska, so my timing was between 10-12 degrees at WOT. I switched to E85, and ran 19* timing without knock. Felt like a completely different car. Even went to as high as 26* without knock, but there's really no gain with that much timing, not to mention all the extra stress it causes.

I am currently running headers, intake, 60lbs injectors, 3.2 @ 21* of timing with 0KR. E85 is the best thing in the world if you can get your hands on it.

Pros: Its ethanol and it works on the same premise of putting rubbing alcohol on your hand and blowing on it. (It gets really cold due to the highish flashover). It cools the cylinder walls as it enters removing KR due to high temps. I have been running E85 for a year now and I will never go back to normal gas.

Cons: As said before, you do lose 30% fuel economy. Also if you live in a cold climate. very cold weather can sometimes cause really hard starts. It was -7 here (-35 after windchill) and I had to crank it three times and let it sit for a good while before driving away. The reason being ethanol does not vaporize at that cold of a temp. So the engine has to ignite the 15-30% gas to warm the cylinders so allow the ethanol to vaporize and explode. It really isnt a massive issue, just have to crank a few times.


What do you need to run E85? 60Lbs injectors for starters due to the 30% more fuel. Headers due to the 30% more fuel. A tuner. I tuned mine my self with HP tuners, If you plan on switching I greatly recommend on learning your self. Makes life much easier when you switch pulleys or something. You will also need a Wideband. DO NOT GO WITH OUT THIS YOU WILL BREAK LOTS OF THINGS WITH OUT IT.

AEM - AEM Wideband O2 Sensor #AEM-30-4100

Tells you the AFR.

EDIT: I just use the Digital Gasoline one and shoot for 14.7 when tuning because 14.7 is a lambda value of 1, therefore there is no point is getting one just for e85.

So worth it though. I spent about 1k on everything I think (Split hp tuners 3 ways with three friends)