Anyone have a flex fuel 5.3

riceman76 · October 30, 2005

I've got an 05 Suburban with the flex-fuel 5.3. I'm curious, has anyone on here actually put E-85 in their flex-fuel vehicle? If so, did you notice any difference in mileage or performance?

Thanks!

asilverblazer · October 31, 2005

I believe it has a higher octane rating, so with proper tuning more performace might be possible, but in general there is less energy in the E85 than regular unleaded, thus less mileage.

riceman76 · October 31, 2005

I believe it has a higher octane rating, so with proper tuning more performace might be possible, but in general there is less energy in the E85 than regular unleaded, thus less mileage.

<{POST_SNAPBACK}>

I thought the mileage wasn't as good, but I was wondering how much difference there really was.

Elwood 2000 · November 1, 2005

My 04 Suburban has a Flex-fuel 5.3 engine. I run E-85 constantly. I have noticed Zero performance change. It runs and drives just as well as with regular gasoline. My "around town" type of driving gets me 13.5 on gasoline and 11.8 with E-85. The spread is about the same for highway driving.

Although E-85 is typically cheaper than gasoline, if you were to total your anual fuel cost with both, I think it would be a wash in the end, or very close to it.

Why do I burn it?? I am a farmer. If I won't use the product that I raise, what good am I??

Disclaimer: This reply is NOT designed to start a flame war over ethanol at ANY amount, but to answer a question asked by a fellow member of this site with the best first hand imformation I have to date.

BlueTahoe · November 3, 2005

I don't use it all the time but I have probably ran 3-4k miles with E85 over the past year. My results are similar to Elwood. I get 14.5-16.5 with gas and 13-15 with E85. I have a westers tune that require 93 octane so my cost difference is generally 50 cents a gallon so I save a small amount with E85. Not much. Basically I loose about 1.5 mpg with E85.

I did the calculation once with cheap gas vs. E85 and it was something like 20$ difference in annual fuel cost. Now that I have to use 93 octane for the tune I think I'm actually saving money but I not in the neighborhood often to get the e85

With the tune I believe I actually get a tad better performance with the E85 but it is very small.

Matt99Z71 · November 4, 2005

Funny, I just called a dealer today to see if I could run it. He said no, the seals aren't correct for it. So if you're set up for the hot tune from westers, can you still burn E-85? Whats the octane equvilanet to?

BlueTahoe · November 4, 2005

If the 8th digit in your vin is a Z you can run E85. I spoke with Lyndon when I got the tune and he said it still allows for E-85 use. I have run E-85 on my 91/87 tune and 93/91 hot tune. The octane of e85 is 100+ so octane is not an issue with the tune.

freakyt · February 1, 2006

Look by the fuel door of your gas cap. The sticker there will tell you if you can run E85.

theplayer · February 1, 2006

Just wondering what is the difference between the flex fuel motor and the regular motor? Also, what is E85?

BlueTahoe · February 2, 2006

I don't believe there are any internal motor changes for flex fuel. It is really a change in the fuel system. Which is pretty much just a fuel type sensor and larger injectors. Maybe a few material in the fuel systems are changed if they aren't compatible with ethanol. I say maybe because non-flex fuel vehicles could still be using 10% ethanol so I would assume all fuel system components are compatible will ethanol on Non flex-fuel vehicles.

E85 is just a blend of 85% ethanol and 15% gasoline.

pm26 · February 3, 2006

all vans and trucks with regular gasoline engine in our Air Force base motor pool were recently converted to run on E85. So it cannot be that costly to do. Otherwise, conversion costs would wipe out any potential savings.