Hod do I size the engine?
Does this figure change w/ rpm and efficiency?


I'm have a mildly streetported 8.5:1 13BT



Thanks,
Ben Martin

 

https://www.rx7club.com/spec-tuning-154/how-size-matters-478915/

 

If you know your injector duties and your AFR I have a calculator that will plot your corrected mass air flow rate.

If you want a copy email me at: rotor_rage@yahoo.com

Justin

 

Unless you know the VE (volumetric efficiency) of your particular setup, plug in 85-90% as a safe bet. Five percent won't hurt your calculations too much. Also, figure CFM as if a 2 stroke instead of a four stroke (most formulas have a factor of 1/2, leave it out).

Yes it changes with RPM; theoretically, you will be consumiong double the air at 6000 RPM as you would at 3000 RPM.

You will want to map many points on the compressor map. Use various boost and RPM levels for these points so you know the efficiency in many different situations.

-Marques

 

Dont be a ***** - put a big **** turbo on that bitch!!!