Supercharger pulley advice needed

Lucifer Sam · 11-07-2007, 01:54 PM

Ok i need some advice, I have 93 lightning that is for the most part stock, except for the powerdyne supercharger which has been with the truck since 94 or 95 im not sure, i didnt put it on. The truck Has 187,000 miles on it, the supercharger has a 6 pound pulley 3.13" diameter i think and 2.93" and a 2.70"
pulleys are available and each are suppose to add 2 psi to the previous one with would put it at 7psi and 9 psi. I looked at the powerdyne site and they gave some info about upgrading something like that and im sure i exactly want to believe it (they said that it isnt boost that damages an engine its the rpms that does) which is true to a certain extent. Does anyone know if i can safely run the 7psi pulley or even the 9psi? I relize that to be more sure on this i would have to do a compression check or even a cylinder leakage test. But i dont go out and race it everynight and beat the crap out of it.

Oh and the s/c has been rebuilt once since it has been put on with ceramic bearings.

Lucifer Sam · 11-07-2007, 02:01 PM

Q: Doesn't running boost on an engine put more strain on the engine's parts?

A: Not necessarily. RPM is what kills engine parts. Typically, an unblown engine has to run up to 7,000 or 8,000 rpm to make any real power. At these high speeds you need a special crank, rods, pistons, rocker arms, valves, valve springs, and on and on. But a blower substantially increases power and torque at much lower rpm's. You usually don't have to run a blown engine over about 6,000 rpm to make maximum power. At these speeds stock engine components are usually more than adequate.
Additionally an engine sees maximum load on the components at the moment the piston changes speed from going up in the cylinder to going down. There is a commonly held theory, too complicated to go into here, that increasing the combustion pressure, which a supercharger does, actually reduces this maximum load when piston travel changes from up to down. Under this theory, at comparable rpm's a blown engine is easier on parts than an unblown engine.
In actuality, as long as detonation is controlled, you rarely have any engine failures with a blower.

This is off the powerdyne website, i dont know some of it sounds a little phony...

11-07-2007, 01:54 PM	#1 (permalink)
Lucifer Sam Registered User Join Date: Mar 2007 Posts: 177 View this user's gallery iTrader: 0 / 0%	Supercharger pulley advice needed Ok i need some advice, I have 93 lightning that is for the most part stock, except for the powerdyne supercharger which has been with the truck since 94 or 95 im not sure, i didnt put it on. The truck Has 187,000 miles on it, the supercharger has a 6 pound pulley 3.13" diameter i think and 2.93" and a 2.70" pulleys are available and each are suppose to add 2 psi to the previous one with would put it at 7psi and 9 psi. I looked at the powerdyne site and they gave some info about upgrading something like that and im sure i exactly want to believe it (they said that it isnt boost that damages an engine its the rpms that does) which is true to a certain extent. Does anyone know if i can safely run the 7psi pulley or even the 9psi? I relize that to be more sure on this i would have to do a compression check or even a cylinder leakage test. But i dont go out and race it everynight and beat the crap out of it. Oh and the s/c has been rebuilt once since it has been put on with ceramic bearings.

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11-07-2007, 02:01 PM	#2 (permalink)
Lucifer Sam Registered User Join Date: Mar 2007 Posts: 177 View this user's gallery iTrader: 0 / 0%	Q: Doesn't running boost on an engine put more strain on the engine's parts? A: Not necessarily. RPM is what kills engine parts. Typically, an unblown engine has to run up to 7,000 or 8,000 rpm to make any real power. At these high speeds you need a special crank, rods, pistons, rocker arms, valves, valve springs, and on and on. But a blower substantially increases power and torque at much lower rpm's. You usually don't have to run a blown engine over about 6,000 rpm to make maximum power. At these speeds stock engine components are usually more than adequate. Additionally an engine sees maximum load on the components at the moment the piston changes speed from going up in the cylinder to going down. There is a commonly held theory, too complicated to go into here, that increasing the combustion pressure, which a supercharger does, actually reduces this maximum load when piston travel changes from up to down. Under this theory, at comparable rpm's a blown engine is easier on parts than an unblown engine. In actuality, as long as detonation is controlled, you rarely have any engine failures with a blower. This is off the powerdyne website, i dont know some of it sounds a little phony...