spark plug heat range questions.
so are you saing my 360 magnum with 14 degrees of initial timing and 9:0.1 compression ratio could run on 85 octane fuel and be completley fine?
Maybe! Try it and see. If it pings, go to mid-test (87). If it doesn't, keep running 85 and pocket the $$ difference.
Because where i live regular gas octane is 85, plus is 87 and premium is 91 octane.
Right. That was how it was up at 5500 feet in the Denver area where I lived for 20+ years, too. Increased elevation --> reduced air density --> reduced combustion chamber peak temperature --> reduced need for octane. The 85-87-91 fuels available at high altitude are functionally equivalent to the 87-89-93 fuels available at sea level.
I have always been to afraid to rn 85 or 87 octane fuel in this magnum.
No reason to be afraid. Drive the tank almost dry, put in a few gallons of regular, and keep your ears open. If it pings, go fill it up with high-test. If not, keep buying regular. Drive it til the tank's almost dry, then put in a few gallons of mid-test, and keep your ears open. If it pings, go fill it up with high-test. If not, keep buying mid-test.
my girl friends 2009 chevy cobalt with a 4 banger rattles on the 85 octane
...which has nothing to do with your car.
so i figured since a 4 banger couldnt handle the 85 octane fuel that my 360 most likely wouldnt like it ether.
That is not how the world works.
