I use whatever kind of gas AAFES buys. It's got 10% ethanol in it, but hey all of the gas down here does now. Also, it's 10 cents cheaper to get gas on base than anywhere else. My last tank I paid $2.56 a gallon and from just under a quarter cost me $35 for the tank. Not bad for 93 Octane I think.

 

BP here for my GXP and when I had my old GTP- it seems like it was better at stopping knock than the same octane at Shell. I put whatever is cheapest in my impala. Right now, I believe the monte still mostly has the 100 unleaded in it from the racing place (didn't know how knock would be with the whipple and higher compression before I got the IC).

 

I use Shell almost every time and Mobil is my secondary. My Monte absolutely runs differently from brand to brand. In particular, Speedway sucks for me. I get worse gas mileage and it runs rough.

 

i usually put in whatever is cheapest around me. marathon, holiday, freedom, etc. any of the gas i've used around here has ran great regardless of the brand. i at least make sure i run marathon through every once in a while since i know they have additives in their gas.