I'm in the process of doing some calculations to predict the efficiency of the turbo I want for my car. Using the equation:

Airflow (cfm)= (cubic inch) x (RPM) x (0.5) x (volumetric efficiency) / 1728

After I add in all the figures for my GSR, I get:

Airflow (cfm)= (109.7) x (RPM) x (0.5) x (.85) / 1728

* I set the volumetric efficiency to this average because a typical I-4 put out about 0.8-0.9*

Now my question is, what RPM should I set? Peak torque at 6200 or peak power at 7600? This is the RPM where I want the most efficiency out of the turbo, that is why I dont want it at redline. Any suggestions? Thanks.


[Modified by fiebru1119, 12:33 PM 8/13/2002]

 

FWIW: VTEC engines have a much higher VE. Many designs reaching over 100%.

edit: damn I can't spell


[Modified by DSF, 12:43 PM 8/13/2002]

 

Thanks alot, I wasnt aware of that. Does anyone happen to know what a good average would be for the VE of a B18C?

 

Average for a stock B18C1 (according to my VE calculator that I downloaded) would be around 95%. A stock JDM B16A (170hp model) comes in aound 105%

 

Thanks! Now about the RPM part, this is where I want the peak performance out of the turbo right? If any of you guys did used this formula, what RPM did you use?

 

I think you'll want to use your max rpm. Don't hold me to it though You may or may not have seen this site...
http://www.turbofast.com.au/javacalc.html
...some good calculators on there. But, like anything that I didn't create myself, I take it with a grain of salt.

 

Great, thanks for all the help DSF