Most of the Unichip tunes are programmed for higher octane fuel. The manual that came with mine says it was 87 octane on one map, and 93 on the other.So after 2 years of debating if its worth paying between $400 and $500 for a Unichip I broke down and bought one. I already had the AEM CAI, TM Duals, Che header and a Che catless downpipe so I figured I might as well complete the circuit. I got my Unichip in the mail the other day and hooked it up and really didn't feel much of a difference driving around town. The seller suggested using higher octane gasoline with the chip....89 or 91, I have always used 87 since I bought my MR2 back in 2007. Will upgrading to 89 or 91 really help improve performance in my Unichip and my MR2? With gas being so expensive these days every penny counts. On a side note after plugging in my Unichip I noticed that my check engine light actually went off....it had been on ever since I installed the Che catless downpipe. Is that normal? Thanks for any advice or info!!
The only time you will gain power with higher octane is when the car is programmed to use it- more timing advance, etc. If the car is tuned to use it, and you're still using 87, there's a chance the knock sensor is retarding timing back to the point where you may actually have reduced power with your unichip.
My advice is to figure out exactly what the chip is tuned for.