New Racetrack near me, non-ethonal gas!

[Subyman]

How would you know it makes 25 more HP unless you had it measured at a dyno?. Since ethanol is less "energy-dense" than gasoline I don't get it. Like I said, the differences were very minor and the car is an '05 model so it would be able to adjust to different fuels. The most noticeable is a slight improvement at idle, it has a little "walk" to it when I run 10% blend vs non-ethanol but again this and it feeling a little "peppier" might be as much in my brain than in reality LOL.
EDIT: Oh, OK, my bad, your using the 85% ethanol blend, I had it backwards thinking you were running 85% gas 15% ethanol.

Because it comes rated from the factory for 25 more hp on ethanol.

 

[Subyman]

The placebo effect works with vehicles, just as well as in medicine.

It isn't placebo. You can see the difference directly from the manufacturer's documentation. It makes sense, E85 is equivalent to 100-105 octane, so the ECU can advance timing, which will give you a bit more low end torque and slightly more horsepower.

Last time I checked, E85 was $1.89. E85 contains roughly 30% less energy than pure gasoline, so it is equivalent to ~$2.70, which is practically what 89 gas costs in my area. The only downside for me is having to fill up more often, but I get slightly more performance (not that I really care at all.)

On the GM truck forums, most won't run regular because the 5.3 likes to pull timing on low octane fuel. Most run 91+ to get better mileage. E85 stacks up decently well in my specific situation.

I'll use E85 if it is available and cheap, but I don't bother to search it out when I need to fill up.

 

[HeXen]

Wish we had non ethanol pumps so I could use it for my small motors and stop buying stabilizer.