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Let's talk flex fuel

Hoon

Hoon

Autocross Champion
Location
Rhode Island
Stija said:
So then you have a unitronic e20 supported tune, dont say no special tune.
Click to expand...

You can run E20 on any OTS tune that I'm aware of.

It's well within the range if what the ECU can adjust for.
 
H

Hans

Ready to race!
Location
NC
Stija said:
So then you have a unitronic e20 supported tune, dont say no special tune.
Click to expand...
It's their standard, E20/93OCT/98RON, 'no special tune'.
 

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Stija

Go Kart Newbie
Location
Az
Car(s)
BMW Saab Subaru VW
So it is a tune for e20, at least allegedly. It may not be specific to e20 but it supports it. Is someone running no tune at all and using e20 going to have the same gains or changes in his powerband as you on the nonspecial unitronic tune?

Also, i dont fully understand how the ecu is supposed to know you are running 20% ethanol to compensate and not run too lean vs running 93oct with <10% ethanol? Is that what you mean by not special because its really a 93oct tune that knocks less on e20 because it pushes the limits on 93oct?
 
2013R

2013R

Drag Race Newbie
Location
Virginia Beach, VA
Stija said:
So it is a tune for e20, at least allegedly. It may not be specific to e20 but it supports it. Is someone running no tune at all and using e20 going to have the same gains or changes in his powerband as you on the nonspecial unitronic tune?

Also, i dont fully understand how the ecu is supposed to know you are running 20% ethanol to compensate and not run too lean vs running 93oct with <10% ethanol? Is that what you mean by not special because its really a 93oct tune that knocks less on e20 because it pushes the limits on 93oct?
Click to expand...

VW's are far more resilient to tune changes than say Subaru ECU's. I have had a lot of experience with each. I would never test a strong E blend on a Subaru without proper tuning, but VW's have much better self-protection. The gains come from higher octane, thus less knock and less timing pull. so the gains come naturally to the strongest your tune can be. You may be losing some power on whatever tune you run with timing being pulled. A slight E blend solves that.
 
Hoon

Hoon

Autocross Champion
Location
Rhode Island
Stija said:
So it is a tune for e20, at least allegedly. It may not be specific to e20 but it supports it. Is someone running no tune at all and using e20 going to have the same gains or changes in his powerband as you on the nonspecial unitronic tune?

Also, i dont fully understand how the ecu is supposed to know you are running 20% ethanol to compensate and not run too lean vs running 93oct with <10% ethanol? Is that what you mean by not special because its really a 93oct tune that knocks less on e20 because it pushes the limits on 93oct?
Click to expand...

You're stuck in the mentality of Subaru junk. :)

The car has factory wideband O2s and will adjust fueling on the fly (within reason).

The difference between E10 and E20 is only about 3% more fuel required.
 
Diggs24

Diggs24

Autocross Champion
Location
de plains! de plains!
Car(s)
2015 GTI
The ECU is smart. All cars are designed to have some overhead on everything so they can work all over the planet in all conditions. This is why you can run some ethanol without issue. Car sees AFR is lean and adds more fuel (because stoich of e85 <pump). But it can only add so much before it decides "Hey, something is wrong I am having to add too much fuel." Then you get a CEL. There is a wideband O2 right on top of the turbo.

Unitronic has adjusted the "hey something is wrong" threshold higher because the car as it is equipped from the factory has overhead to do so.

That's it in simplistic terms.
 
2013R

2013R

Drag Race Newbie
Location
Virginia Beach, VA
Both replies very agreeable to me. VW's have better more advanced tuning than a lot of similar cars.

Diggs24 said:
The ECU is smart. All cars are designed to have some overhead on everything so they can work all over the planet in all conditions. This is why you can run some ethanol without issue. Car sees AFR is lean and adds more fuel (because stoich of e85 <pump). But it can only add so much before it decides "Hey, something is wrong I am having to add too much fuel." Then you get a CEL. There is a wideband O2 right on top of the turbo.

Unitronic has adjusted the "hey something is wrong" threshold higher because the car as it is equipped from the factory has overhead to do so.

That's it in simplistic terms.
Click to expand...

Hoon said:
You're stuck in the mentality of Subaru junk. :)

The car has factory wideband O2s and will adjust fueling on the fly (within reason).

The difference between E10 and E20 is only about 3% more fuel required.
Click to expand...
 
acegp1

acegp1

Passed Driver's Ed
Location
Seattle, WA
Car(s)
2018 VW GTI SE
Bumping this up from the dead; does anyone know if Flex-Fuel is being implemented on the COBB AP?
 
2slowvw

2slowvw

Moderator
Location
VA
Car(s)
2022 Tesla Model 3
It is funny how flex fuel has been available on other tuners for a while now and not cobb
 
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