Theres gotta be an error somewhere in my thinking here....

Wouldnt higher compression send exhaust gases expading out even faster and thereby spooling a smaller turbo quicker? Isn't it just the pressure in the combustion chamber at the point of ingniton all that matters anyway? So 10:1 comp with 9 psi of boost would yield the same out put as 9:1 comp with 10 psi of boost? If thats the case then why swap in lower comp pistons when it's only going to make you have to run more boost, out a bigger, laggier turbo just to get the same output as with high comp, and a small turbo?

Like I said...I'm probably wrong somewhere in there, but I'd like to know where..

 

the higher you're compression, the more arrow your window of tuning....there were a few threads on this a few weeks ago...i think you could find them if you did a search for "compression"...i think it was "best b18b compression" or something liek that....

 

A smaller turbo at more psi will not yield the same hp and tq curve as a bigger turbo at less psi.
In general:
"To obtain higher than stock outputs, the compression ratio should be LOWERED on a street turbo. This will permit higher boost with optimized timing on low octane fuel. "

 

Most of what you said is right. But the power will not be the same between the two ratios. A higher comp ratio will spool a turbo faster, but if the turbo is matched properly to the engine and boost being run, a lower comp leval will be better.

The Turbo will still spool very fast but you have the ability to have more power with more efficency, and more ability to boost higher.

The lower CR is also best because it results in a more controlable combustion. The tuning can be more leaniant, and the car will be more reliable. This is not to say that you can not get a high CR to run reliably, but it just gives you more of a window for error in tuning.

 

BLAH!

 

Makes sense...might as well have the opportunity for more boost there when I want it