Not sure how to determine if i have a stock supercharger pulley or a modified one. Need to replace the serpentine belt and see that there are different sizes depending if you've upgraded the pulley. How on earth do I tell if I have stock or modified? Thanks! Haven't started the belt replacement yet - just prepping. Wanted to have proper belt on hand.

 

Pretty easy to tell. Most aftermarket have a name or % of reduction on them. Here is link to a pic of a stock one.
http://s287.photobucket.com/user/bra...re028.jpg.html

 

good chance if you look at the pulley and it has bolts/holes in it, its aftermarket =)

 

Stock pulley is steel....black...hot pressed on...no bolt holes, no fancy machining...
Aftermarket has been made on a CNC machine, USUSLLY colored, often imprinted with a name and % reduction.....very different....on all but the EARLIEST tries at reduction pullies from many years ago....think 2003....
So if it is black...steel...smooth on the side, no bolt holes...it is oem. Aftermarket has bolt holes and often several holes to lighten them up cut in them....

 

Awesome! Thanks for the tips. I anticipate this is a OEM job since nothing else is modded but wanted to be sure.

 

Well if it's oem slap a 15 on their!!

 

How do the various pulleys change the driving?

 

Easier to drive because it gives it a good hp boost.

 

A 15% pulley will change the car enough for your butt dyno to notice, as well as inducing a smiling face on the driver.

 

If you aren't going on the track with it, bump it down to a 17% pulley.