View Single Post
Old 01-16-2002, 12:39 PM   #1
Addict
Zoom-Zoom
 
Addict's Avatar
 
Join Date: Sep 2001
Location: Ohio
Posts: 3,924
Question on the turbo formula sticky....

I'm not sure I follow the formula that's listed.
I used THIS CALCULATOR to get my CID.

1.6 Liters = 97.63200 Cubic Inches

(97.63200 x RPM x 0.5 x VE) / 1728 = CFM

What do I enter for my RPM?
How do I figure my Volumetric Efficency? I know the average is 0.8-0.9.

(97.63200 x 3000 x 0.5 x 0.8) / 1728 = 67.8

Alright. I'm guessing this is correct. So moving on to the next part.
Quote:
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

This lost me. Let's say my boost desired was 10psi.

(14.7 + 10)/14.7 = 1.6802721088435374149659863945578

That doesn't seem right. Though I guess it could be. What is the (NA-CFM)? Is this a formula too? Also where can I find a compressor map?

Quote:
Heres 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

Low : 0.052 x 67.8 x (10 + 14.7) = 87.08232
High : 0.077 x 67.8 x (10 + 14.7) = 128.94882

Sorry if I sound stupid, I'm just trying to make sure I understand this correctly.
__________________
Quote:
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

Last edited by Addict : 01-16-2002 at 01:02 PM.
Addict is offline   Reply With Quote