I tried the search button tonight but its not working for some reason so I apologize if this has been talked about before. Ive been a long time reader of this site and finally picked up an 09 SS/TC last month. But I was wondering if the stock tune likes 91 or 93 octane gas better? I live in Oklahoma where finding 93 is like finding a needle in a haystack. I did finally find 93 last week and ran it to empty and barely got 240 miles on the tank. Ran 91 again at the beginning of this week and am 275 miles on the tank with still an 1/8th of a tank left... so maybe i got bad gas on the 93 fillup or the car just likes 91 better? Car is totally stock and I drove the same on both tanks.

 

doesn't matter 91 & 93 isn't too much of a big difference
If its hard to find 93 octane then stick with 91 dude

 

I noticed a little difference in performance with the Sunoco 94 octane gas. Not a big difference, just seemed a bit peppier.

 

Car definitely runs smoother on Sunoco 94 than on Shell 91.

 

there are 2 gases I have found that it liked on stock (not running stock anymore, but still), they were Shell 93 Octane (my personal favorite) and BP/Amoco 93 Octane, tonight I'll be trying some higher octance gas from sunoco...the one where i'll be going has 107 or 110 Octane unleaded, so my plan is to mix that with a few gallons of my 93 Octane to get around 98 or 99 Octane...I'm running at the track tonight for the first time with the GMS1 and Catless Downpipe...so watch for times

 

Well since 91 is what most places have go with the 91. I dont know about where you are at but here the 93 has 10% ethanol and ethanol is bad mojo. But I do like Shell and BP gas they seem to work the best.

 

Only the 93 has 10% ethanol? Up here (I'm in Delaware) everything is 10% ethanol...unless you go to like VP Racing, but their stuffs expensive. You cant get anything thats less than 10% here...my car's been fine on it...

 

so is it bad to mix race gas ex anything over 100 with pump gas for a half a tank, then after the track go back to 93? I just wanna make sure its not going to hurt anything or if it would b just fine. thanks.