Whats the significance of 91/93 octane tuning? What does tuning the engine for a higher octane really do? Does it really boost that much performance over a tune for regular 87 octane besides saving gas money?

 

I'm wondering about that also..

 

anyone anyone

 

I have been playing with my Diablo Tuner I increased timing to the 10% max in both ranges I am now getting the best gas mileage I have ever gotten in my 04GT I am seeing around 26mpg driving 70 and 24 at 80. I learned that here and I am convinced it helps and thats on 91 octane.
Chris

 

In a nutshell. It's not the octane that gets you the power increase, it's advancing the timing, but that will require a fuel with more octane (REMEMBER all octane is the fuels ability to resist pre-ignition).

 

jd1969 is correct.

The tunes basically give more advance the higher the octane number.
It would seems that the 10% is based on the maximum allowed for that tune.

 

oh thanks. So when you advance the timing, you need to run higher octane so the engine wont knock due to pre-ignition?

 

You can increase it. The Predator has a VERY CONSERVATIVE "canned tune". I ran a Predator and when I bought my Steeda timing adjuster Brenspeed.com told me to run at least 6* additional timing and unlike the Predator's 10% increase in 2 rpm ranges the timing I added worked throughout the entire rpm range, not just at WOT so it sounds like you are doing some WOT running to work! Check the tuner as it lists the % of timing you are adding or subtracting is at WOT. I added 6* on top of the 10% of the Predator tune and got no knock. Like I said the steeda timing adjuster as sold by Brenspeed.com raises the timing throughout the rpm range. Brent highly recommended it and I bought it...from somebody else but also bought UDP's from him so he was kind enough to assist me with the timing adjuster, really cool guy so when it was time for a cutom tune I bought my SCT from him. 3 custom performance tunes for 3 octanes-87, 91 and 93. I am awaiting it to come back now as he is replacing the 91 tune with a 100 octane tune as we have that octane unleaded here. If you're getting a Predator I can help make nearly a custom tune for a good price so PM me if interested in what I believe to be the best bang for the buck. Mark