Possible to afvance timing when alcohol is detected in the fuel with flex fuel logic?

[Perna00]

I converted my 3.5 Gen 2 Ecoboost over to E-85 and would like to get some of the gains with timing. I'm going to try to always use an ethanol based fuel for it but would like a safety net if possible, in case it isn't available in a particular area or not easily accessible. I know that knock detection can reduce the timing but not sure about the limit or damage that may occur from the differences in E-85 vs 91/93 depending on fueling available. Some vehicles have a borderline timing table based on FFV but mine does not. Any ideas?

[SiriusC1024]

Only for PE, which is probably what you're looking for anyway.

- ECM 44585
- ECM 44586
- They reference ECM 33782 and ECM 33784

As you can see from the spark tables, at lambda=1 there is no spark modification. Basically, Ford is saying that there is no need to differentiate for alcohol content unless the engine is under high load.

Don't fool around with the knock sensors.

[Perna00]

Thanks, I might have to go that route for the modification. I was hoping for one with adjustments for alcohol in case I’m even somewhere without E85 fuel. If I adjust timing based on PE and then end up having to get 91/93 octane, would the knock sensor response be enough to prevent damage?

[SiriusC1024]

Yes. As long as you don't touch the knock sensor settings it'll be safe. Besides, you should be leaving the lambda EQ for 91/93, hence timing there, alone.