Compression ratio for built engine?
 

What compression ratios are people with high HP built engine turbo builds running and more importantly, why that ratio? Speaking with a tuner they recommend 9:1 going down that road but from what I've seen most everyone seems to be running 10:1 and getting in the upper 500HP all the way to 600HP range. Is there an advantage to the lower compression at those power levels? The car would be running 93 octane gas.

Lower compression allows for more power
Higher compression allows for better response

Most chose the happy medium of 10:1

fixed for you:tup:

The reason you would want lower compression for a boosted engine is to lower your chances of detonation..aka engine knock, so you can push in more boost

I should specify, I know the general reasons behind going one way or the other but was curious about it more specifically in regards to our engine. As in, what kind of response or power might be lost by lowering the CR, how much higher might the ceiling be with a lower CR setup?

Hopefully that clarifies what I'm asking a little better.

Other factors will come into play with headroom of power/response along with CR. What fuel are you planning to run, any additional cooling adders (meth?), what is the plan for the power?

I know we are not a fan of GTM at this point. But Sam recommends 11:1 even on a built engine shooting for lots of boost. Especially if you are running E85 to ward off knock.

The higher compression will get you that better low end power and will also get your turbo spooling up quicker. We all want faster spool! :excited:

I'll be running 93 octane exclusively and currently have no plans for anything like meth. The car will be driven at least a few times a week on a lower than max power setting likely in the range of upper 400-lower 500HP possibly turned down a little more.

And what are your goals for full power?

Sorry for the slow response, work got the best of me.

I'm shooting to break 600 on high boost and daily it likely high 400s, maybe a little more or less depending how that feels. I'm used to the 425ish my Stillen puts down so we'll see where exactly it's settled.