E85 vs Gasoline

[outrider]

So hopefully my first post here won't be a stupid one

I'm coming to EMU from the AEM world, and my first install is on my single turbo 2jz mk3 supra. The car was running e85 on the AEM (so it's what is in the tank currently).

I'm getting close to turning the key, and trying to wrap my head around the the fuel calculation formula. Base on the fact that a flex fuel sender can be used to blend two VE maps, as well as AFR target maps, it would appear that if I wanted to make the startup map e85 friendly, I would simply add VE (probably to the tune of around 30%, and tune it from there).

I just want to confirm I understand this right. I can see it would definitely work, even though it doesn't seem like the fuel type actually changes the volumetric efficiency. It's really no different then in AEM world simply telling the injectors to put more fuel in the engine at a particular load point. I just want to make sure there isn't some setting I'm overlooking that tells the ecu the energy density of the fuel or something.

Cheers!

[RHD]

There is an Ethanol fuel scale factor in the setup for flex fuel. If you use that correctly then the VE tables will be nearly the same!

[BigMac]

I did this a few years ago and came up with a number of 17% increase for E85 . Let us know what you come up with

[Karel]

me about 40%

Just calculate it.

Lambda 1 = 14,7:1 for gasoline and 9:1 for Ethanol

[outrider]

Will that work even if the EMU doesn't see an input from a flex fuel sensor? My setup doesn't have one, I've always just ran e85 in it.

I don't have an issue with using the VE maps either. I was just trying to understand if that's the right way to approach this, since it would seem like fuel doesn't change the pumping efficiency of the engine. I also noticed there is a per injector trim, I'm guessing I could just add ~ 30%-40% to each of those, and tweak from there. Then if I added a flex fuel sensor down the road, I could just back out the trim and enable flex fuel.

On another note, the car fired right up after some generous increases to the idle area of the VE map. A little hesitation on the accel enrichment (it's going lean, no surprise there). But I can already tell I like the EMU way better than the AEM V2. Car has never idled this good, 675 rpm and purring like a kitten. I suspect a lot of my previous issues was due to a questionable MAP sensor, but I do like having all my sensors wired direct to the ECU, and having the built in MAP. It's eliminated a lot of wiring and potential points of failure.

Now to justify to the wife spending the extra couple bucks on the Black for my Datsun. No dear, it's not just cause it's in a cool looking case...

[Karel]

i will not recommend to run E85 without flexfuel sensor.
Normative for pump E85 sais that you will have 60 to 85 percent ethanol and rest gasoline. So you never know what you get. We have in Summer cca 78percent ethanol in it, and 62 in Winter.... but this is only our Gasstation we use.
You need to have map for gasoline and ethanol and blend between them using FF sensor

[outrider]

Ok that's sound advice. I've honestly never had a problem, I've always bought my fuel from the same place. But as soon as I read your response some part of brain said "Doh, you knew that."

So I will do that, and I guess that really solves the rest of the issues in itself. Thank you!