whats the hp diff between 8 and 11 psi pulleys

novaspyder

Registered User
on a 91 supercharger... how much horsepower would i lose downgrading to a 8 psi pulley instead of the stock 11?

also how much is gained by getting a 10% smaller 11 PSI one over the stock 11PSI one?
 
trife86 said:
why would you wanna downgrade and make 8psi over 11psi :(

because this setup is on my mustang, and im kinda wary about running 11 psi on stock internals... even tho my blower is ported and i have duals with catless H pipe
 
Are you running a jackshaft? If not, your diameters are going to be way different from the SC.

This thread has a spreadsheet in it you can download that helps you calculate pully RPM's for given pully sizes.
http://www.sccoa.com/forums/showthread.php?t=54113&highlight=excel

You can also look at the charts on eaton's website to see the RPM's for a given boost factor.

Boost in itself isn't inherently dangerous. It's detonation in the engine due to a stock or poor quality tune.
 
yes i have a jackshaft... and i though high boost was dangerous because it will cause your piston rings to die faster as well as possibly your head gasket
 
Certainly the clamping force of the heads, connecting rod caps, main bearing caps will be tested as horsepower is increased above standards. As can a crankshaft. Pistons in general are damaged more by detonation than just horsepower, though yes, ring lands can crack and excess clearance in the motor can cause issues.

The major causes of engine failure though, specially in forced induction motors is detonation. this is especially a problem with the Eaton M90 due to the heat it generates the faster it spins.

It's certainly wise to start low.
 
Mike8675309 said:
Certainly the clamping force of the heads, connecting rod caps, main bearing caps will be tested as horsepower is increased above standards. As can a crankshaft. Pistons in general are damaged more by detonation than just horsepower, though yes, ring lands can crack and excess clearance in the motor can cause issues.

The major causes of engine failure though, specially in forced induction motors is detonation. this is especially a problem with the Eaton M90 due to the heat it generates the faster it spins.

It's certainly wise to start low.

thank you for the help..... appreciated :cool:
 
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