s arnold

does anyone know what the the max compression i could run on 93? i have a 306 with gt40p heads, explorer upper and lower, an x-cam and 24lb injectors.

turbosha

theres alot of variables. depending on tune ive seen 10to 1 just have to watch detonation.9.5 to 1 would prob be best. then spray the crap out of it.

94StinkinLincoln

i know personally 10.7:1 is ok.
the cam events play a part, quench and other things start to matter once you hit around 11.0:1

mjr46

get a set of aluminum heads and you'll find you can run more compression...I ran a .200 dome piston on 58cc alum heads making about 11 to 1 on 93 octane and never had detonation once

94StinkinLincoln

I have a -5cc flat top, 52cc head, .039 compressed gasket, about .010 in the hole, with a 3.25 stroke and 3.030 bore. it comes out to like 10.7:1
i ran either 91 or 93 and a total of 29* so far. spark is kinda low but i havent tuned it yet.

67mustang302

Way too many variables to say. How aggressive will the tune be, what's the quench, what type of piston, what quality piston, chamber shape, cam timing, intake, exhaust etc etc. Also how much margin for error do you want? Running it on the edge works fine and all, until you get some bad gas or a lazy trucker puts 87 in the premium tanks.

w8less

i doubt this guy doesnt even know what the quench is without looking it up

94StinkinLincoln

nothing wrong with that, he can look it up and ask questions about it to further his knowledge.

AdderMk2

my CR is around 11.25:1 and I use pump gas no problem