Sixx

Does anyone know who would have the best ethanol free fuel tune?

movielover40

I've heard good things about the Bama tune.

SCCAGT

Well, this is new.
The ECU in every car these days already has the ability to compensate for ethanol fuel percentages. Lets gets some details out of the way first.
-The injector pulse width is how long the injector stays open.
-The ECU uses the O2 sensors, MAF, and throttle position, etc, to determine how long the injectors stay open.
-Injectors are sized according to cylinder displacement.
-Under wide open throttle, an injector is ideally at about 90-95% capacity.

To keep it short, no ethanol vs e10-e15, means the ECU can easily compensate for the difference in the amount of fuel needed for optimal combustion. You do NOT need to go out and get a specific tune for non-ethanol gas, as the ECU already has the capability to handle it both ways. After all, all the testing, tuning, and EPA figures are done with non-ethanol fuel anyway.

jwog666

^ this

Sixx

Very interesting SCCAGT. Thank you!

Stangbass

Really the only thing that will change from a E10/E15 to a non ethanol tune will be the stoich scalar. This is what tells your engine at what point the optimal burn point of the fuel that you are using. This is about the only time AFR is referenced in this fashion the rest of the calculations are based on lambda which remains the same despite the fuel content. The difference is something like 14.64 for pure gas and IIRC 14.11 for E10.

Your engine will use the oxygen sensors to adjust the fuel trims to compensate for the amount of ethanol content in your tank.
HOWEVER, when your car enters open loop mode it no longer uses fuel trims and relies solely on your MAF readings/calculations to determine the amount of fuel to spray. Which means if you are running E10 on a pure gas tune, and enter a open loop condition like WOT, it will cause your engine to run lean as ethanol requires more volume to reach stoich. Usually this isn't a huge deal on more conservative tunes but if you are pushing the ragged edge on a boosted engine lean isn't somewhere you want to be. Fortunately ethanol tends to be more resistant to detonation.

So whoever you get to write your tune just tell them you will be running ethanol free gas and they can set your scalar to 14.64.

Nuke

I'd also be surprised if it's worth including in a tune.

Stangbass

This is the only value that would need to be changed. Change this value and all subsequent fueling will adjust to it. Anyone with the ability to write a tune will be able to set this value to whatever you want it.

This is one of my race tunes, where I am running about a 60% ethanol to 40% 93 octane. I can easily switch between Pure gas, E10, MS109, E50-60, etc just changing this value. All the base fuel tables are in lambda and will adjust to whatever the stoich AFR is. So in WOT fueling I run .79 lambda. Running pure gas this would be a AFR of 11.57/1. Running E50 it would be an AFR of 9.36/1.

But simply put just tell whoever is writing your tune that you plan on running pure gas and they can set your scalar to 14.64. Either way it's not a big deal on the majority of tunes. My stock tune was set to pure gas(14.64)

SCCAGT

Just confirmation that there is no reason to waste time/money to alter what he already has.

jz78817

why would you need a tune? the factory calibration can account for anywhere from 0-10% ethanol.