Originally Posted by ZzzZz

What's the highest Octane our stock ECU can effectively utilize? 91? 92? 93? 94?

Here in California, the highest is 91 but I've been able to try 93 and 94 as well.

I know there will be doubters but the 93 definitely had an impact on performance. The engine ran smoother, with that harse noise near redline every magazine describes becoming less clattery and more throaty. Throttle response was improved and so was MPG. Response going part-throttle was greatly improved.

The 94 made the engine seem lazy and out of breath. The engine is quieter going through the RPMs than the 91 but throttle response was bad and it seem to rev up slower.








Just yesterday I was low on gas and decided to finish off my 93. I drove spiritedly and made note of overall sound and feel. Once it was on empty, I filled up a tank of 91. Immediately I noticed a difference in engine sound in the mid to upper RPMs and throttle response.

Since this was just my perception I was looking to try and get others' experiences and try and align my butt-dyno with a real dyno (concrete #'s).