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Old Jul 27, 2011 | 09:53 PM
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tom2112
She can ride with me ;)
Joined: Sep 2007
Posts: 3,399
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From: Sharon, PA
Default Re: Supercharger Pulley Modification

Just for reference (especially because I know that I'm going to want to look this stuff up later):

Stock Crank Pulley is 154.4mm
Stock Supercharger Pulley is 74.2 mm

Equation to determine RPM or size of a pulley:

(Crank Pulley Diameter) times (Crank Pulley RPM) = (SC pulley diameter) times (SC pulley RPM)

or
Cd * Crpm = Sd * Srpm
So, if I've got a 185 crank pulley, and a stock SC pulley (74), and the engine is running at redline (6,200 rpm) the SC pulley will be spinning at:
185 * 6200 = 74.2 * Srpm
Srpm = 15,458
And I want to see what size SC pulley would equal a 185 crank pulley:
154.4 * 6200 = Sd * 15458
Sd = 61.9 mm
Or, if I want to know what the crank pulley equivalent of a Code3 65mm SC pulley is:
154.4 * 6200 = 65 * Srpm
Srpm = 14,727

Cd * 6200 = 74.2 * 14727
Cd = 176.2 mm
(OK, that makes me feel better. The Code3 is only 150 rpm (supercharger rpm) slower (or about 1%) than the 178 mm crank pulley setup.)
 

Last edited by tom2112; Jul 28, 2011 at 11:03 AM.
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