Mackenzie C

since you could get the same power numbers from a higher compression motor and low boost vs. a lower compression motor on high boost. i was wondering what would be the highest safe compression on a f/i motor? and im talking fully built bottem end, sleeves, crank, rods, pistons, etc...

lkailburn

its not really possible to tell. there are a billion factors that would determine if your motor would last with X compression and Y boost with Z tune and A-W parts in it.

i would advise you to run low compression and high boost.

Mackenzie C

i guess you can say that, but assume that everything was premium, the parts, the tuning, the boost, then what would you say? 10:1 sounds good, what do you think?

Snoopy

it's all in how good your tune is. tony the tiger on h-t is running 12psi or something like that with 11:1 c/r. but he's a very good tuner.

lkailburn

you will be good on 10:1 but you'll need a good tune. good fuel management and a good fuel setup. don't cheap out.

my mini-me's around 9.9:1 and im boosting

b16ahybrid

Even premium parts differ the outcome. It all depends on how much power you want to make. If your looking for 350whp or less then higher compression is fine for the street, if your looking for more power I would advice a lower compression. Both can be done and both will make great numbers.
I think it was the vennom civic that was running compression in the mid 11's with boost, thats back when it ran 10's.
Most people when they build a motor shoot for about a 9.5:1 compression. You can go higher if you like. Most of the high compression cars are probably stock motors. I ran 10.2:1 compression with my stock b16a..tuned w/hondata it put down about 285whp on 13psi.
If your building a street car I would say stick with 9.5:1 - 10:1 compression, if your building a track car go with 9:1 -9.5:1. My current build is going to be running 9:1 compression, but i'm also shooting for about 450whp.

Mackenzie C

yeah its going to be a street car, and 300whp would be the goal for me, and 12 sec timeslips.

Provocateur

If those are your goals, a 9.5:1 c/r is fine for you.

A high compression turbo motor will make more power, but tuning becomes more difficult and race fuel must be run.

Mackenzie C

cant you just make the car run richer to compensate for the higher compression?