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How long for ECU to adjust to E85 blend

TroyI

Ready to race!
Location
Austin, Texas
Planning on going to the drag strip and want to blend a couple gallons with 93 octane to get the fastest run possible. I only will do this once since I only go to the drag strip a couple times a year.

Question: How long does it take the ECU to adjust? Will it adjust in just 50 miles of driving?

I would be switching back to only 93 octane immediately after the drag strip day.
 

pieguy

Ready to race!
Location
Bay Area
You won't notice any real performance benefits unless you tune for the ethanol mix. You'll only notice a few gallons of ethanol splashed into a tank of 93 in terms of smoothing out idle, knock prevention, etc.
 

Navi

Autocross Champion
Location
BK/NYC/Hamptons

ZuMBLe

Autocross Champion
Location
NY
Car(s)
Alltrack 6MT
I've been browsing through the JB4 threads looking at logs of APR stacked cars. None of the cars showed any crazy timing corrections. All showed conservative timing with "aggressive" boost. Nothing alarming that would suggest APR tunes have crazy knock. Let's stop spreading these falsehoods.

APR has canned tunes for some pretty expensive cars. It's hard to believe their tuning style would cause crazy knock, or even come close to blowing up engines on the regular. They simply wouldn't be in business anymore.



with their tune, you probably need a little ethanol in the tank to prevent crazy knock... lol
 

Chogokin

Autocross Champion
Location
So Cal
Car(s)
GTI Sport | Audi A3
I'd give it ~15 miles for the ECU to adjust and the fuel to mix.

I'm only have a Neuspeed module...and with 3.5 gallons of E85 in the 7psi mode...I can feel a very noticeable difference in acceleration.
 

Twist1

Autocross Newbie
This is a good question. I run up to e25 with my Apr stage two 93 Oct tune stacked with +1-2 jb4 sometimes and meth (since taken off).

I am very familiar with both Apr and jb4 maps at this point. So adding e does two things I've noticed: 1) allows the ecu to run its full timing advance more easily (limited by the tune and iats however). 2) helps prevent knock.

It can take up to 30-60 miles until I FEEL any difference or see any in the logs. On the biggest of differences, you're looking at maybe 1-2 degrees of timing on an ots map.

Don't really know where the whole Apr tune being knocking thing came from. I run APR and put down 352whp and 416wtq with E and a little M. Apr is very fuel sensitive though. Because it's so boost heavy it naturally buffers safety through lack of timing, and the car will slightly knock if 93 is not really 93 just like any tune, but e can help avoid that . A little knock will always happen from time to time though..
 

Navi

Autocross Champion
Location
BK/NYC/Hamptons
I've been browsing through the JB4 threads looking at logs of APR stacked cars. None of the cars showed any crazy timing corrections. All showed conservative timing with "aggressive" boost. Nothing alarming that would suggest APR tunes have crazy knock. Let's stop spreading these falsehoods.

APR has canned tunes for some pretty expensive cars. It's hard to believe their tuning style would cause crazy knock, or even come close to blowing up engines on the regular. They simply wouldn't be in business anymore.

I'm talking about the MAPerformance tune.. I was running it for awhile. That's what I saw. Same with a couple other people.
 

ZuMBLe

Autocross Champion
Location
NY
Car(s)
Alltrack 6MT
Ah okay. I thought you meant APR because the other link says APR tune. Any logs of the MA Performance tune? I'd love to see it. Well, in theory the MA Performance tune would do great on some ethanol then! Haha.

I'm talking about the MAPerformance tune.. I was running it for awhile. That's what I saw. Same with a couple other people.
 

Joel

Ready to race!
Location
TN
From watching my gauge the E85 is mixed within 3-5 miles even if E85 is put on top of a full tank of reg.
 

Navi

Autocross Champion
Location
BK/NYC/Hamptons
Ah okay. I thought you meant APR because the other link says APR tune. Any logs of the MA Performance tune? I'd love to see it. Well, in theory the MA Performance tune would do great on some ethanol then! Haha.

No, I don't have any logs of it, but it was knocking like a mofo. I ended up getting their 91 tune instead of 93 tune and running it with 93 octane so that I wouldn't get any knock. Ended up going protune after bc I wanted to run 93 octane with a 93 octane tune that wasn't detonating all over the place. Honestly the COBB OTS had less knock than the MAP tune. But yeah, my point was ethanol would have fixed it lol.
 

JerseyDrew77

Autocross Champion
Location
Virginia & NC
Car(s)
2016 TR GTI S 6MT
No, I don't have any logs of it, but it was knocking like a mofo. I ended up getting their 91 tune instead of 93 tune and running it with 93 octane so that I wouldn't get any knock. Ended up going protune after bc I wanted to run 93 octane with a 93 octane tune that wasn't detonating all over the place. Honestly the COBB OTS had less knock than the MAP tune. But yeah, my point was ethanol would have fixed it lol.

Which version of their 93 tune did you have? The reason I ask is I've been running their 93 tune since May and it's been pretty good so far.
 
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