Last night I decided on a whim to fill up with 91 octane fuel and retune the truck, in part because the station I was at had ethanol free 91.

Let me say, huge difference, just pulling through the lot to leave you could feel it had much more power, and it runs much more smoothly. If anyone else has a tuner with a 91 setting that they haven't tried, try it, it made a huge difference for my truck and it looks like I'll be making the change permanently. I have to look at how my mileage is on the 91, but so far I'm very impressed with it.

 

My buddy says the same with his 08, what kind of tuner do you got?

 

Same thing with my 99 f150 4.6 4x4 and my edge cts.

 

Superchips Cortex

 

let us know if there is a big difference in mileage.

 

Will do, I'm doing a run from Rochester to Albany mid april which I've done several times and average 20mpg on with 87 octane, we'll see how it goes.

 

well i filled with 93 and retuned my truck and it ran like **** and got terrible MPG. but if i feel with 87 i get over 350 miles per tank and excellent power.....oh and im lifted 5in with 35s

 

I'm on an 87 tune. I just filled up on 87 too. Next time the truck is empty, mid-end of april most likely, I'll retune for 91.

 

thats because when you retune your truck it advances the timing just a little bit which makes it have a little more power and get better gas mileage. your going to have to mess around with it for a while. I can run the #3 Performance tune on my edge cts with 93-95 octane and if I dont hot rod around I can get right at 80 miles on a 1/4 of a tank. retuning takes advantage of exhaust fuel pressure intake air temps and cai's. not to mention a ton of other stuff.

 

I generally push about 550 miles between fill ups, we'll see how this tank holds up. I'm doing a 500 mile run in mid april, so we'll get hard numbers after that.