I am wondering if anyone can give me some clarification between a reduction pully and a supercharger pully? I have been reading lots of posts on ppl deciding on them for their cars, but worried about warrenty issues, I want a 15% recuation pully I think. However, I need more info first..

thanks.. guys...

 

A reduction pulley is the supercharger pulley; just smaller. The reduction causes the supercharger to spin faster, giving you more boost, earlier on.
Some dealers frown on such things warranty-wise, some don't. You'll need to ask yours which group they fall in to.
If warranty is of overriding concern, you could consider the JCW pulley (14.6%) and have your dealer install it. Since it is a MINI part, no warranty concern.
Hope that helps.

 

Huh? AFAIK MINI does not supply just the JCW pulley. You have to get the whole kit.

 

My mistake. Sorry.

 

There are tons of 15% red. pullies out there and posts regarding them here on NAM. They are safe, best bang for the buck, and will transform your car. Just do it! Or search for info on here till your eyes bleed and then u will do it anyway. or at least that's what I did in March '03 w/ my Aug '02 build MCS. Just to date my pully, it's a heat seated one, not a bolt on.
Have fun

 

Lest you think that his pulley has heated seats , in the days of the dinosaur, a friction fit pulley was heated up in an oven, then placed over the SC shaft, where it cooled and shrank, creating friction fit. Modern pulleys are two piece taper fit - an inner piece is placed over the shaft, and the pulley is screwed on to it and the tapered inner piece grips the SC shaft.

 

So how does the crank pully fit into this whole thing?

 

Crank pulley is another place to gain some S/C speed (by going oversized) and to shave some weight from the rotating mass. There is an ongoing debate (to put it mildly) on whether you open up the possibility of lower end damage by removing the harmonic balancer (part of the crank pulley). Similar weight savings can be achieved by going to a lightweight flywheel, but that is much harder to get to and more expensive.


ps: the search option is your friend.

 

Going with a larger diameter crankshaft pulley will also cause the supercharger to spin faster for a given RPM (along with the air-conditioning compressor and the alternator).

The aftermarket crank pullies are also lighter than stock, which helps the engine spin up a little faster. The weight reduction isn't as drastic for the 05/06 models, since their crank pullies are lighter to begin with, compared to the earlier cars.

You can overdrive the supercharger as much as you need with a supercharger reduction pulley alone, since they're available with up to 19% reduction. Anything more than that, and you're pretty much just beating the crap out of the air and heating it up, not getting any additional performance.

If you're going to do both pullies at the same time, I'd use a supercharger pulley to get the boost, and a stock-diameter lightweight crank pulley for the weight savings.