Has anyone here seen significant powers gains from any form of pulley kits?

 

ASP replacement balancer pulley. Forget about anything else

 

You will not gain much, because there's not much being driven by the serpentine belt. Its not like a 3rd Gen, where you have the water pump and AIR pump driven by the belt.

Here's a link to a dyno test:

http://www.ws6.com/mod-2.htm

 

http://www.ws6.com/bangbuck.htm

 

You have to realize however that thoswe dyno test are with a bolt on type piggyback pulley.

The ASP is a replacement pulley, so you get the slight underdrive effect, but most of the gains come from reduced rotating weight. They are good for a solid .1 - .15 at the track.

 

I had the march pulleys. They claim 11 rwh but I didn't notice a thing.

 

I had the ASP integral 23% UD pulley damper and the 15% UD alternator pulley, and was unable to measure any improvement. It wasn't worth it to have the volt meter dive into the red when the engine was idling and any sort of electrical load was on.

 

I saw a car on the dyno put down 15 RWHP 10 RWTQ more just by removing the belt so obviously there is some power used to turn things. I have the march underdrive crank only and don't have any charging probs even with the A/C and stereo cranked. I bought the pulley more for saving the accessories from spinning so fast than for performance.

 

That really suprises me. I just had the Pulley, (no alternator pulley) and never had charging issues even running fans, electric h20, and stereo at idle. Lowest I ever saw was high 11 ish volts. Yes thats little a strain, but never really worried me. Once the cam went it i bumped the idle a touch and it was even better.

I gained .10/1mph on my car with it on, and was actually faster with it than no belt (guessing too low voltage with no belt). All runs had similar weather and 60's. Saw some other cars locally gain even more.

 

I gained about 5mph (from 99 bone stock to 104) with the TB bypass, Borla catback and the March UD/OD pulley set. I know 1 mph was the bypass but I'd credit most of the other 4 to the catback. I dont think its worth it unless you get them used or if you think every bit counts. I didnt mind putting the pullies on. No charging issues ever. I'd say save the pulley mod until you run out of things to do.