octane rating and engine performance
In Texas, the minimum octane rating is 87. On a recent trip to Glacier, I noticed a lot of the fuel in states like CO, WY and MT, the octane was 85, and you had to buy the mid-grade to get 87 and abov...
Forum Discussion
Even back in the '90's when we were towing with a '76 Chevy 350 cube V8 and a '97 Vortec 4300 V6...when we towed I would put premium fuel (91 octane). Other than that I would use Regular (87 octane) for everyday driving. Either way I never noticed any engine knocking or pinging. The newer Vortec automatically adjusted it's timing and /or knock sensor and compensated for lower octane gas. I'm pretty sure the '97 manual (Vortec V6) recommended high test gas when towing and that's what I filled up with, towing.
