I did some searching and it seems many have the view that crank pullies for our cars are bad but nobody had any solid evidence that it was harmful.

Then I got thinking, the supercharger guys are all running aftermarket pullies? Have any S/C motors failed from crank vibration taking out the main bearings?

Just bought a set for a good price but my buddy is convinced I should only use the waterpump and alternator pulley and ditch the crank one.

Any insight is greatly appreciated.

 

or you could turn the boost up .00001 psi to make the hp you would get out of pullies.

 

Not worth it IMO

 

Waste of moneyz

 

Yeah I know its not going to be any significant HP gain but I wanted to clean up my engine bay. I picked them up for $45 for the set so it wasn't a large investment.

But I am curious is running a S/C not the same as installing an aftermarket crank pulley without a lace for the supercharger belt?

 

All the supercharger kits add on to the factory dampened crank pulley.

 

If you want to "clean up" the engine bay, use the accessory pulleys and keep away from using an after market crankshaft pulley.

 

Well rather than turn this thread into a poll (which I could have created but it's not my intention) let's keep this topic on strictly knowledge/experience basis.

We all know many cars are pushing hp numbers on the stock engine that people tbought wern't possible before. Where are the people who said it couldn't be done? Of course they are nowhere to be found or left dumbfounded and speechless.

I'm following another similar topic with intellectual input on Honda-tech which I will link shortly but I wanted to see if I would get any informed responses first.

The oem pulley is NOT counter weighted specific to any crank or motor. Therefore it is NOT a harmonic balancer! Instead what is debatable is the rubber impregnated inside the pulley to apparently reduce any harmonic frequencies.

Anyone with an educated or experience based reply please respond, otherwise save your opinions for the polls!

John

 

Looking to Wickipedia for a quick definition of harmonic balancer:

A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.[1][2]

Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.

To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations.

Additionally the energy transferred from the piston to the crankshaft can induce as much as 2 degrees of twist in the crankshaft, which has many follow-on effects on all engine elements that require adequate timing such as valve opening, cam timing, ignition timing etc.

Over time, the energy dissipating (rubber/clutch/fluid) element can deteriorate from age, heat, cold, or exposure to oil or chemicals. Unless rebuilt or replaced, this can cause the crankshaft to develop cracks, resulting in crankshaft failure.

Performance enthusiasts have been known to remove harmonic balancers, usually when the balancer is attached to the crank pulley, deciding that they aren't necessary and their mass reduces the performance of the engine. However, this is unproven and potentially very risky because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high.[citation needed]

Certain cars, however, do not come equipped with an external balancer on the crank pulley, and as such, can have the pulley replaced with a performance oriented product which counter-act these resonance frequencies.

My impression is there does not need to be a counter weight for it to be a harmonic balancer.

 

after above post. i hope you get any thought of using that aftermarket crank pulley outa your head. if you still use it, u are asking for problems.