Wich turbo would be best for a 500+hp gsr?
t4 .68ar 60-1 .70ar TO4S or
prescision pt61 gt35r t56 .68ar
Wich would give more hp w/less boost?
Also what other differances would you see between the two?? such as hp and rpms, tq curve, turbo lag, ect.. also how do you read the first one i listed? what trim is it? is it a bigger turbo than the prescision?

 

a n y o n e ?

 

anyone at all??

 

Because of all the questions as to which size turbo should I use here’s a little info I found on how to get a rough idea as to which size turbo to use and how much power you can expect to get from it. All you need is a little basic info and the compressor maps (any reputable manufacturer will supply them). It’s a lot of calculating but it works.

1. Calculate the airflow for the engine in naturally aspirated form. Use this formula for standard atmospheric pressure: (CID x RPM x 0.5 x VE) / 1728. The airflow rates will be in CFM VE stands for volumetric efficiency usually 0.8-0.9

2. Knowing the desired boost level, calculate airflow rate under boost by multiplying the pressure ratio by the airflow rate (NA-CFM). To figure out the pressure ratio take (14.7 + boost) divided by 14.7.

3. If you are running twin turbo divide the total cfm under boost by 2.

4. To convert CFM to lbs/min, use (CFM x 0.076 = lbs/min).

5. Use compressor maps to find the turbo best suited to the airflow rate and pressure ratios you have obtained. Here’s a low and a high range for horsepower expectations Low: 0.052 x CID x (PSI boost + 14.7) = BHP High 0.077 x CID x (PSI boost + 14.7) = BHP