Iv been meaning to get a underdrive pully for my car, but I didnt in time.

The rotating assembly has been sent off to be balanced with a stock one.

So my question is, Are they even worth it? I do want every little hp out of this motor and im not worried about AC/PS at idle. And if i do end up getting one, it really wouldn't make a difference on the balancing would it? I feel weird with a stock pully setup and a 12.5lb flywheel

I'v heard good and bad things about them, someone told me they have had problems with the belts coming off and such.

 

I guess belts coming off depends if the crank hub is on the crank snout properly and the quality of the pulley used. I have no idea if they're worth it. I think I've seen reports of a few rwhp gained, but I've always believed small variations like that on a chassis dyno could be from engine temp fluctuation. I would say they are worth it if you want the accessories to last longer. If you are going to run an underdrive you definitely want to use an overdrive for the alternator or you may end up having a dead battery w/in a few months.

 

I use the ASP 945103 set with the integrated dampner. It's neutral balanced and 2-3 lb lighter than stock. Never had an issue.

 

Ya I've just put them on this morning and I got to say even when you don't have your lights on the amp gauge sits at the top of the yellow. Also I noticed that since it's in the yellow from the start it almost feels like turbo lag. Gains feel ok I guess but minimal. So I guess if you live in a colder climate time will tell how long your battery lasts when it gets cold. Would putting on the stock ALT pulley help or just in time fry my alternator?