Asp underdrive pulley kit or Slp underdrive pulley???

[99Ls1fever]

Hi I was very intersted to see what info was out there on this. I wanted to buy a under drive pulley. I saw that slp makes one and is quoted at 8 hp gain. Also i was searching underdrive pulley kits and found ASP underdrive pulley kit that also come with a altornator pulley too and claims 12-15 hp gain does any body out there which can voice either way? thanks
Matt 99 Camaro 336.8hp and 342 trq. at 5,800 ft above sea level

[Sunset T/A]

I have the SLP on my 02 T/A and like it. Just bought an ASP alternator pulley, but have not put it on yet. Just to get a little more charge on the battery since I rarely drive the car. Most people think that ASP is the only one to buy, but SLP is really good.

[INMY01TA]

Dont need the alternator pulley with a 6 speed.

[99Ls1fever]

why dont you need the altpulley with the 6 speed?

[INMY01TA]

If it's the overdrive alternator pulley it's more for A4s to prevent charging issues while idling with your foot on the brake.

[99Ls1fever]

will it free up the old alt. pulley tention or restricton for more hp?

[INMY01TA]

will it free up the old alt. pulley tention or restricton for more hp?

An underdrive alt pulley would, an overdive wouldn't. I just have the crank pulley on my M6.