Before I had my car reflashed by Works, (P2 for 91 octane), I used to run 93 octane in the car with the original ECU. I felt like there was significant benefit to the higher octane gas. My understanding was that stock Evo's are meant to be run on 94 octane.

Since I am now flashed with Works P2 Brainflash for 91 octane gas, is there any discernable benefit to running 93 octane gas?

 

Yes there is a noticable difference when running 93.

 

the way our gas is now. its up to you if you want to, and you'll feel much more power =D

 

Evo's respond better to high octane

If you plan on always running 93, then I would recommend going to the 93 octane P2 flash software to take full advantage of the better fuel.

 

I have the P2 flash for 91 octane and when I mix 3 gallons of 76 100 unleaded with 10 gallons of 91 octane it equals about 93.2 octane and either there is an "easteregg" program for the 93 map in my 91 flash I figure I am getting 10-12 more wheel horsepower from my butt-dyno; this thing is a rocket on that mixture, and the only problem with the 93 P2 here in California is the crappy 91 octane we are stuck with and the inability to use 91 octane with the 93 P2 flash. I am looking forward to the 296 cams and the P2 re-flash for those in the near future.

 

This answers my original question and confirms my subjective feelings as well. I can see how running 93 octane gas would be beneficial over 91 octane with the OEM ECU, I didn't know if that would be the case with the 91 octane P2 reflash. Now that I've had a chance to run 93 octane for a few tanks, I feel like my evo runs harder and smoother on 93 octane evenn with the 91 octane p2 reflash.

 

Yes, the car (in theory) can run more timing with better fuel...