foxbod90

i have a basic bolt on mustang running 13 degrees timing. my friends friend was turning up his timing on a much much hotter motor. i asked him if he is running premium fuel and he said no because hes got the same compression! i thought to myself, um.... ok ive been using premium this whole time because ive heard over and over again to use premium! whats the deal? should i continue usin 93 ?

AdderMk2

87 is all you need

foxbod90

ok. why have i heard to run premium to avoid pinging?

AdderMk2

because people are stupid. Those are old rumors, from when the world used 100% gasoline. E10 fuels that are used now burn cooler, and are more resistant to pinging. My 11.25:1 347 stroker CAN run on 89 octane, WILL run on 91 octane, but ony runs 93 octane... then again, I adjust my timing tables electronically... I don't just crank on the distributor and think its good.

primetime5.0

I run 87 in mine with a bunch timing, I do however live in the clouds.

foxbod90

does runnin 93 hurt it?

AdderMk2

no, but you are wasting money, and giving up good HP

foxbod90

alright ill back off on the octane.

nitrous_bob

exactly, and some people will even tell you that you make more power with more octane, when in fact it REDUCES combustability of fuel....to reduce knocking...and makes you lose hp

i spray my car on 87 if its nice and cool out. when i was in cali.....i sprayed a 100 shot on 87 octane, 14* timing, and it was closer to hot than cool

it ran its a$$ off but i wouldnt do it again. i just forgot to drop down a bit on the timing, and needed to spray on some fool to embarrass him in front of his girl

67mustang302

I run 91 in my 10.3:1 331, mainly cuz it's a road race setup and I stand on the gas at lower rpm with a bunch of timing and slightly taller gearing than most setups.