E85 Tahoe

Don't yell at me if this is stupid but is anyone running E85 on a fairly stock tahoe? If so, any perks or drawbacks?


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From what I've read on here most say it's not worth it.

Tons of topics on it floating around; just search.

MrBalll said:

From what I've read on here most say it's not worth it.

Tons of topics on it floating around; just search.

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Okay, thank you


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When I run E85 I get slightly less power and slightly worse city mileage but Highway mileage is same. And E85 here is usually over a dollar cheaper than regular.

So...
City, power, towing. Go with regular.
Road trip. Go with E85.

BTW I have a lead foot.

I run it when I can in my work tahoe. Needs to be about 30% cheaper to break even. With a tune (maybe on newer models without) you WILL make more power. But at a loss of mpg.

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I have a custom HP tuner tune, headers, aftermarket Hughes cam, K&N CAI and several other add on's.
Pros: Running E-85 I notice a better throttle response and seems to run stronger.
Cons: I loose about 1/3 mpg's.

Jackle1886 said:

I run it when I can in my work tahoe. Needs to be about 30% cheaper to break even. With a tune (maybe on newer models without) you WILL make more power. But at a loss of mpg.

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That is impossible. With 2 identical vehicles (other than one being flex fuel and the other not) with the same type of tune, compression, etc it is impossible for the E85 to make more power OR even get the same MPG on any road.
Its a scientific fact that E85 BTU output is 81,800 BTU/ Gal and regular unleaded (No ethanol) is 114,100 BTU/Gal and Regular Unleaded reformulated (E10) is 111,836 BTU/Gal.

There is just no way possible to get more energy out of E85 vs. Regular unleaded or even "watered down" E10. All this translates to the fact that it costs more per mile to drive on E85 than regular unleaded at current U.S. prices. Why would you want to pay more to drive? Ethanol cant hurt cleaning out your injectors but thats about all its useful for unless you are into making farmers richer.


So you will use more E85 to drive the same distance that you would using regular unleaded. There is NO magic in a flex fuel vehicle PCM. It has a flex fuel lookup table for fuel injection control which allows MORE fuel to the cylinders when using E85. Hell the flex fuel vehicles (5.3L) use the 6.0L higher flowing injectors because the standard 5.3L injectors wont flow enough fuel for engine demand when using E85.

Anyone tells you anything else is either a farmer selling corn or just completely FOS and in denial.

E85 is perfect for higher compression engines because its octane rating is high enough to prevent detonation. And as we all know octane rating HAS NOTHING to do with HP output.

The only thing you're forgetting is timing. Increase the timing increase the power output. You said e85 has a higher octane rating. Meaning you can increase the timing without predetonation.

GM even posts separate numbers on regular vs e85. See http://www.lsxmag.com/news/power-numbers-released-for-gen-v-5-3l-ecotec3-and-4-3l-truck-engines/

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Jackle1886 said:

The only thing you're forgetting is timing. Increase the timing increase the power output. You said e85 has a higher octane rating. Meaning you can increase the timing without predetonation.

GM even posts separate numbers on regular vs e85. See http://www.lsxmag.com/news/power-numbers-released-for-gen-v-5-3l-ecotec3-and-4-3l-truck-engines/

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What you are forgetting is at what RPM? Bottom line it costs more money to run E85 per driven mile than regular unleaded. 8 more HP doesnt get you more miles. I can put in 92 octane and get more HP by advancing more timing in if you wanna go there. You cant use the outcome of apples and oranges.

rockola1971 said:

Bottom line it costs more money to run E85 per driven mile than regular unleaded.

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It really depends on what the price spread is. It costs me about $.18 cents a mile to run E85 or $.21 cents a mile to run gasoline at current prices.