i was reading on a couple of different 408 stroker kits and one of the kits stated comp ratios of:

11.1:1 69cc combustion chamber
11.6:1 64cc
12.1:1 58cc
13.1:1 54cc

can you even run pump gas on these compression ratios?? it just seems really high. thanks in advance

 

You could probably get by with 93 with the 11.1, the 11.6 is pushing it, but it also depends on the dynamic compression, in other words how big of a cam you want to run.

 

You can run pump gas on really high compression depending on the build but like the man said, it has to do with dynamic CR and chamber design. Some chamber designs really resist detonation well, others not so much. 11:1 is a good ratio that won't leave you having to pull timing if you decide to drive to Cali where all we have is 91 octane horse ****. 11.6 is right at the limit of where I'd go.

 

My Audi ran fine on 93oct with an 11:1 ratio. That's about as far as I would ever go on a pump gas car. Of course, you could always run E85 (aka 104oct) and go a little higher

 

my stock mustang right now is 9:1 ratio (i think thats correct) and im running about 10* of timing so i can run 87 octane and it runs, ping free.....i deffinetly dont want to run anything above 10.5:1 compression. I just want a nice street terror sleeper

 

With aluminum heads and good 93 octane it should be ok. Not possible if you run iron heads.

 

So whats a guy with a audi doing on a mustang forum?? former owner or trying to become one?