Here are a couple shots of the new and old OEM pulleys. They are definitly different!

Although if you look at it there is very little dampening ( rubber ) on the new pulley

new is on the left.

 

I just weighed the 2 to see just how much difference there is.

Old pulley = 7.2
New pulley = 5.1

So there is roughly 2 pounds difference.

 

 

Are they both from the same model car?

An MC has a single isolation crank pulley, but an MCS has a dual isolation pulley.

This was to move the resonance of the Super charger, drive belt and pulley to an rpm below the normal operating points of the engine.

John

 

I think the change to the lighter crank pulley was made in '05 -- here's an explanation from Randy Webb.

 

they are both for th esame car, just a new version vs the original one. If you go into the dealer and ask for a crank pulley you will get the lighter one as it has replaced the heavier one.

Personally I have tried the 3%, the 0% light and the lighter stock one and I perfer the lighter stock one, smoother throughout the range and idle is smoother. At least in my car, I have all the motor mounts upgraded with powerflex

 

Have you got a part number for the new one?

Great post.

 

11237514461

That is the ONLY part # for a crank pulley now. The old one was dropped and the number replaced the old one. I looked at an 02 and an 05 and they list the same # that I posted, and that is th eone that weighs 5.1#