Just ordered in the mrz underdrive crank pulley. I will also be doing my alternator pulley. If im not mistaken there is a Crank bolt that is needed to install the pulley. Does anyone have the size or part number for this. Also, what tensioner works best to rent?

 

Cobalt addiction has the crank bolt cobalt-addiction.com

 

Is it necessary that i change the bolt?

 

I would just to be safe they are a torque to yield meaning that onced torqued down to spec they should not come off

 

^^^ Correct, replace the bolt. They are meant to be used once! Factory service manual specifies this. The part number is 1158912? -- crap the tag on my new bolt is torn at the end!!!!

Found my old picture:

https://www.cobaltss.net/gallery/fil...nce_pulley.jpg



https://www.cobaltss.net/gallery/sho...08&c=favorites

PN is 11589123...LoL

 

just how much power can u get out of these pulleys?

 

^ You won't make much, if any, noticeable power, anyway. It's for freeing up power, and quicker revs.

 

Technically, you want make ANY...you are merely freeing up. As for example, it takes 10hp to turn the stock crank. The new one might take 5hp to turn.(Keep in mind these are BS numbers). You free'd up 5hp...so if your car was at 200hp...you'd be at 205. The engine itself isnt making any more...you're just seeing the increase due to the engine not having to turn a massive crank.

 

Great explanation!