Up here in Canada they dont sell 100% eth anywhere that Ive seen but last weekend I drove to NYC and noticed it at practically every gas station. I wanted to try a tank out but being on the road and far from home I opted not to. Just wonder what anyone thinks of it in stock flex fuel trucks? Worse/better/same power?

 

Didn't know you could get straight ethanol in the States. I think there are only 2 E85 stations in all of Ontario. I know GM rates the 5.3 at 11 more HP and TQ on E-85 over 87 octane.

 

I maybe feel a slight performance gain with E85 but lose 4 mpg in my 2010 ECSB 5.3.

 

When i had my 11.6:1 406 in my EL Camino i ran E85 in it and then retuned and rejetted it for 93.. Way better performance on E85..

But then again i just measured gas consumption in the meano by fun per gallon..

the throttle in that thing is just a switch.. OFF or ON!!!!

 

There are more gains to be had if you are tuned for it. If not, the performance and/or mileage increases will be minimal.

 

Performance should be the same on E85 as premium. Since the max power rating for the 6.2 trucks is 403 on 91 octane, it is unlikely you will gain anything by running anything with a higher octane because the truck has no factory tuning to take advantage of it. If they had timing tables set up exclusively for performance on E85, then the peak power wouldn't be rated at 403hp on 91. It would be rated at 4xxhp on E85. On a factory tune you WILL lose mpg on E85 for sure.

 

If you have a 5.3 there are two seperate sets of tables; 1 for E85 and 1 for 87. You will gain performance and lose fuel mileage on E85. A 6.2 truck also has two sets of tables. 1 is for 87 and the other for 91. On 87 you lose performance and mileage. On 91 you have 403hp and optimum mpgs. On E85, you have the same power as 91 but you will get lower mpg.

 

tuned for 91 vs tuned for e85. e85 is faster.

there are tables for gasoline, adders, and wot afr vs timing tables. same goes for e85. part throttle timing does not change. there is not a table for 87 octane. you are confused with the low octane tables. the ecm resorts to this under high knock issues. after so many key cycles it will flip back to the high octane table. the ecm can not tell what octane you put in the truck. it can see the alcohol content and adjust the stoich accordingly.

i myself run e85 in my truck. the torque difference across the board is far greater than pump gas.

 

After I get my headers/catback insalled I need to get a tune and am tempted to go for an E85 tune since I can run it no problem with 3 stations within 4 miles of my house, all on the way to work or anywhere else I would be going. My question is this: What about when you go out of town and have to run 93? How does it run on the 93 when tuned for E85?

 

I wasn't referring to tuned vehicles, just stock. I know that the tuned performance of a vehicle should increase, at least marginally, as it gets tuned for 87>91>93>E85. However, on a stock 5.3 peak power is rated on E85, with losses to be expected on 87 and no premium power rating at all. This led me to believe that there is a table to take advantage of the E85's qualities, which would make it advantageous (from a performance standpoint) to run E85 in an untuned 5.3 FlexFuel truck. However, on a 6.2 FlexFuel truck, peak power is rated at 403hp on 91 octane. Since there is no power rating on E85, and E85 is capable of supporting more power than 91, I assumed that they had no tables designed to optimize the vehicle's performance on E85 and therefore it would only produce as much power as it did on 91+ octane premium. This would mean that it is in no way a performance advantage to run E85 in an untuned 6.2 FlexFuel truck. That is all I was trying to say. I don't know anything about the actual tables in the ECM, as I have never tuned a vehicle. What I do know is that the ratings are adjusted based on the fuels being used, and this is what I'm going on.