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Discussion Starter #1
What's the maximum ethanol blend the ECU can handle? some guy from Versatune told me is E15(15% ethanol).
 

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Presuming that the e85 is really e85, not seasonally blended down to e70 or sometimes even lower, as is often the case here in the US, and that the pump is e10, again not seasonally blended

In a speed6, with a 16 gallon tank, I would not exceed 2 gallons of e85, and really less is better- one gallon of e is enough to feel things smooth out and to troubleshoot KR issues, 1.5 gallons, or if really needed up to 2 gallons of e85 for more additional troubleshooting but not for daily driving.

considering 16 gallons and true e85 & e10
p - e = %
16 - 0 = 10%
15 - 1 = 15%
14 - 2 = 19%
13 - 3 = 24%

Due to the extra O2 that e85 brings to the party once you reach 2+ gallons you need to tune for the specific ratio being targeted- that is, you need to tell the ECU what the new Fuel Specific Gravity (FSG) is so that Stoich can be properly maintained. Without making that adjustment to the fuel tables the car will run lean.

Since ethanol, simply as an additive, does not make power, rather you actually lose power, the only common reason for running it with an untuned ECU is for troubleshooting knock, typically to verify if really an ignition issue or an actual hardware noise issue seen as knock by the ECU- with e the symptom will clear up if ignition issue, but if hardware there will be no change to symptom.

Hope that helps.
Also- isn't this just a refresh from the same conversation two years ago?
 

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Discussion Starter #3
Presuming that the e85 is really e85, not seasonally blended down to e70 or sometimes even lower, as is often the case here in the US, and that the pump is e10, again not seasonally blended

In a speed6, with a 16 gallon tank, I would not exceed 2 gallons of e85, and really less is better- one gallon of e is enough to feel things smooth out and to troubleshoot KR issues, 1.5 gallons, or if really needed up to 2 gallons of e85 for more additional troubleshooting but not for daily driving.

considering 16 gallons and true e85 & e10
p - e = %
16 - 0 = 10%
15 - 1 = 15%
14 - 2 = 19%
13 - 3 = 24%

Due to the extra O2 that e85 brings to the party once you reach 2+ gallons you need to tune for the specific ratio being targeted- that is, you need to tell the ECU what the new Fuel Specific Gravity (FSG) is so that Stoich can be properly maintained. Without making that adjustment to the fuel tables the car will run lean.

Since ethanol, simply as an additive, does not make power, rather you actually lose power, the only common reason for running it with an untuned ECU is for troubleshooting knock, typically to verify if really an ignition issue or an actual hardware noise issue seen as knock by the ECU- with e the symptom will clear up if ignition issue, but if hardware there will be no change to symptom.

Hope that helps.
Also- isn't this just a refresh from the same conversation two years ago?
Nope I don't use E85 I use E15 which is the only avaliable at my local pump right now.
 

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Regular fuel is already blended 5%-15% depending on where and from who you buy it. Most gas in Canada is 10%, but you can find places with 91octane+ that they say is ethanol free.

Gasoline is stepped on hard in North America, always assume you're running 10% unless you have a REALLY trustworthy source.
 

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Discussion Starter #5
Here is Spain RON 95 gas has a maximum of 5% of ethanol by volume and 2,7% of oxygen by volume.RON 98 gas has no ethanol.E85 is not avaliable in most pumps like E15 which also is not very avaliable.In comparisson France has E10 in mostly all the country with E85 also in majority of pumps over the country.
 
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