if you car says only use 93 octane and use 89 whAT WOULD happen?

 

more details..what car?
mainly loss in performance, if not detonation.

 

i was just wondering.. my boy has a caddy truck that only takes 94 or 93.. i forget.

 

I don't know Caddies, so here's a general answer.

If the car doesn't have a knock sensor, it'll get spark knock, especially when you're into the gas pedal. If you keep doing that for a long time it'll damage the combustion chambers. Maybe put a hole in the top of a piston??

If the car has a knock sensor, it'll back off the spark timing so it won't knock. You'll have less power, maybe enough to notice.

 

it seems strange though for the car to require only 93 octane when its not availible in all states. here in cali pump is 91