Flex fuel tune vs E85 only tune

[Silver50Pony]

I'm curious on anyone's inputs on the power difference between say lund flex fuel tune and the e85 tune. The flex fuel I know you get awesome power gains but I wonder if there's a noticeable difference in power? I'm guessing with the e85 only tune of you get e85 one fill up and e70 the next it may not be a good thing, not sure if there's any adjusting for the difference in ethanol.

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[Burkey]

I have both from Lund. Haven't dynoed it but there IS a seat of the pants difference. The ignition timing alone tells the story.

 

[dubster99]

My dedicated E85 tune peaked around 32 vs 30 on the FF tune. Not much difference at the top, but the timing ramped to peak much faster than the FF tune. The midrange picked up a good amount of power. Jon Lund II told me that he tested timing on his personal 2015 gt, and didn't see any power increase or ET improvement going over 30 deg. Take that for what it's worth.

 

[Burkey]

My dedicated E85 tune peaked around 32 vs 30 on the FF tune. Not much difference at the top, but the timing ramped to peak much faster than the FF tune. The midrange picked up a good amount of power. Jon Lund II told me that he tested timing on his personal 2015 gt, and didn't see any power increase or ET improvement going over 30 deg. Take that for what it's worth.

From memory, I picked up about 6-7 degrees in the midrange. Which explains the seat of the pants feel. A couple up top also.

 

[Jn2]

When I rented the dyno to dial in VCT I tested my flex fuel tune against my e85 tune. The e85 tune put down 1whp more than the flex fuel tune.

As long as the ethanol percentage in the tank is the same on both tunes and the flex fuel fuel tune is set up correctly(modifiers/multiplers) it will make the same amount of power you would make on a straight e85 tune. In my case both were seeing 32* of spark advance and both were running .85 lambda with the same VCT angles

 

[Sasuketr]

My dedicated E85 tune peaked around 32 vs 30 on the FF tune. Not much difference at the top, but the timing ramped to peak much faster than the FF tune. The midrange picked up a good amount of power. Jon Lund II told me that he tested timing on his personal 2015 gt, and didn't see any power increase or ET improvement going over 30 deg. Take that for what it's worth.

I had the same problem, my flex fuel tune on E85 peaks at 30 degrees of timing, however, same tune with the shell nitro 93 octane also peaks at 30 degrees of timing without a knock, making 93 octane put down more power. 8 whp and 10 lbft to be exact. Now i have seen people getting 36 degrees of timing from ff tune on E85, but they specifically requested higher degrees of timing, and their cars are knock proofed.

 

[V8EATR]

E85 will never really allow for actual KR but timing over 30* like mentioned isn't going to do anything.

 

[Silver50Pony]

Thanks for everyone's input, I'm sure the reason im feeling such a difference on e85 compared to 93 cause my Max timing on 93 I was only seeing 27 so I'm sure if I'm getting 30 or 31 I'm getting a good gain .

 

[jlstro3]

I have both the FF and e85 "race" tune that lund offered me. I do like the midrange feel of the e85 only tune better, timing ramps in a lot quicker. Up top I'm not sure I felt much difference, log showed upwards of 33 degrees compared to 30.5 or so w/ the FF. I honestly don't know if It made much difference at peak.

 

[Jn2]

I have both the FF and e85 "race" tune that lund offered me. I do like the midrange feel of the e85 only tune better, timing ramps in a lot quicker. Up top I'm not sure I felt much difference, log showed upwards of 33 degrees compared to 30.5 or so w/ the FF. I honestly don't know if It made much difference at peak.

It's also not about peak timing, you want to look at your actual spark curve, say you are peaking 31* with -6 KR, this means you were making around 24-25* when you went WOT and then KR slowly added timing from there until it reached it's peak value. What you want to do is look at your curve and see if you can give yourself that timing so you don't have to wait for KR. So that way you end up with 31* of advance but it's only -3KR, this means you were 28* before KR started stepping in. You could go higher, but I usually like to do 28* max on 93 and let KR add from there, 30* for e85(then let KR add from there)

 

[jlstro3]

I'm definitely not an expert on tuning, but from looking at the spark curve from the logs for my FF tune vs my e85 tune the spark curve comes on much sooner than the FF tune.

 

[Silver50Pony]

Does anyone think or has anyone found that with most bolt on NA coyotes with flex fuel tuning that a 50/50 mix of E85 and 93 will get you just as much gains as all e85? The car doesn't feel much faster on my flex fuel running all e85 compared to the 50/50mix.

 

[Jn2]

Does anyone think or has anyone found that with most bolt on NA coyotes with flex fuel tuning that a 50/50 mix of E85 and 93 will get you just as much gains as all e85? The car doesn't feel much faster on my flex fuel running all e85 compared to the 50/50mix.

That's because you pretty much get the full octane effect of e85 around e60...I see 30* of spark advance on 93 right now, doing e85 just give me more knock resistance. Which allows consistent spark and lets me do a extra degree or two

 

[dubster99]

I had the same problem, my flex fuel tune on E85 peaks at 30 degrees of timing, however, same tune with the shell nitro 93 octane also peaks at 30 degrees of timing without a knock, making 93 octane put down more power. 8 whp and 10 lbft to be exact. Now i have seen people getting 36 degrees of timing from ff tune on E85, but they specifically requested higher degrees of timing, and their cars are knock proofed.

So on the same day, same dyno you swapped fuels and made more power on 93? I find that a little hard to believe with how cool E85 burns...it's automatic power.

 

[dubster99]

Does anyone think or has anyone found that with most bolt on NA coyotes with flex fuel tuning that a 50/50 mix of E85 and 93 will get you just as much gains as all e85? The car doesn't feel much faster on my flex fuel running all e85 compared to the 50/50mix.

If you get a dedicated E85 tune, you will feel the difference. Running a mix will probably get you to the same peak timing around 30ish, but it won't ramp in as quickly.

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