A question for Works or others:

I have done a search on EvoM and found conflicting info. What is highest fuel octane rating, (R+M)/2, that the stock 2005 Evo ECU can take advantage of (I presume by varying timing, boost, etc...) to make more horsepower? The prevailing opinion seems to be 93 to maybe 95, but I was wondering if anyone has ever really tested this on a dyno or at the track?

If the stock ECU can use a range of fuel octane, what about the Brainflash? I notice you guys sell them with 91 or 93 "maps", but would a reflashed ECU be able to beneficially use higher octane fuel above the "map" level?

With my stock ECU, I have used a mix of Union VP 101 unleaded with 92 unleaded at Thunderhill and the car definitely felt faster but I sure couldn't quantify the gain. I was kinda busy........

Thanks in advance,

Mark

 

I'm running the P2 for 91 octane. I run 92 octane and still feel some good gains if i mix in race gas or xylene.

 

Mark,
When my EVO was bone stock, I ran the 1/4 mile to see what it would do with 93 pump gas and straight 100 CAM2. My times/trap speeds were virtually identical. Once I moved west, crossed the Mississippi and hit the 91 octane, I felt a small decrease in performance, but nothing to quantify it with.

With the WORKS Brain Flash, we narrow the window of the octane to optimize the effeciency of 91 or 93 gas. Using a higher octane fuel than what you're flashed for could either increase or decrease performance depending on how extreme you go with it. 92 octane fuel may help on a 91 octane flash if you were running in less-than-ideal conditions.