I do understand that higher compression means more horsepower at a given boost level and generally quicker spool up, but lower compression means higher potential boost levels and invariably more total power.

does that mean the 9.0 CR will spool alot more faster than the 8.5 CR or there wont be much difference?

my ultimate goal is to get 500-550whp out of the TN kit. I'll be using JWT cams and a shortblock which consist of Eagle rods and Arias pistons (.020 overbore 8.5 or 9.0 ED). And yes I do know that the Arias extreme duty pistons are the best in the market, on the other hand I can get the regular arias for half the price of the ED.

I dont like to sound like cheap but based on my power goals what do you guys think will best suit my needs?

 

I drove an 8.5:1 turbo G35 yesterday and couldn't even feel the difference from my stock motor turbo Z............go 8.5:1 if you want. Either way 8.5 or 9:1, the differences are negligible

 

thanks chimmike.

anyone else?

and what is the compressor efficiency of the TN kit?

 

We use 9.0:1 on 99.9% of our motor builds...that CR is the "sweet spot" between great response out of boost (tough to tell the difference between 8.5:1 and 9:1) and the CR is still low enough to not be detonation-happy at low boost levels. With your power goals, you will be fine with 9.0:1, and you will be able to reach your goal with LESS boost...as long as the tune for A/F and timing is dialed in and not too aggressive, you will be JUST AS SAFE with say 550rwhp on 9.0:1 CR at 16psi, as you will be on 550rwhp on 8.5:1 at 18psi- but your turbo will not have to work as hard

-TODD

 

I have 9:5:1 compression in mine going in here soon. I've always believed that going up slightly in compression, would yield better turbo response as well as driveability. Plus it will help people with larger turbos.