Unorthodox Underdrive Pulleys???

i was lookin aroung for performence mods, and i found these Unorthodox Underdrive Pulleys...they all claim to give 10-28 HP, for only $170-200. Whats the deal with these? Are they bad for the car? i know they short power in the airconditioning and stuff, but if they give 10-28HP, how come no one ever talks about them, or has them?
If Anyone has one, or know why not to get one, please let me know...cause i need some HP's bad!!
p.s.-, the one for the 3.0 V6, is the same for the 2.4 I-4
Check out http://www.indigospeed.com/GTPullies.html

The reason no one has them is because to get that HP they teake it from other aspect of the car. For example the alternator pulley causes the alternator to work less efficiently there for freeing up power for the longshot...they are also alot lighter which allows them to be spun easier. Basically on an everyday driver its not a good idea because it takes power from vital systems that we use...

Marc :twisted:

I know a kid who got pulleys for his car and its an everyday driver, and he was having nothing but problems with them after a week. The alternator went, his amp went, everything. So I don't recommend them unless you just use the car on race day.

Here we go again. If you use just the crank pully you won't have the severe problems that underdriving causes. The HP gain comes from weight reduction of the crank pully. Don't use the alternator/accessory pully. You only get about 15% of the gains from there. The reason people arn't using these pullies like crazy is the crank pully trips the SES light. It signals a engine missfire to the computer. There is another member having custom crank pully made now with no underdrive but about 6 pounds ligher that should net you some good hp gains at a good cost.

Wes

Yeah, all the ppl i talked to said not to use it if you have a system or anything, but i dont have anything like that. I want the speed now, ill get the accesories later, so all my alternator has to worry about now is the air conditioning. i never even have to turn mine up to 4...i usually only need it on 1, so i have room, or power to spare, right?
plus, it's ok if the SES light comes on, and the engine thinks its misfiring, as long at it not, right? I dont care if the lights on...as long as my engine still works! But if this goes bad ill be spending a lot more then $200. i guess i just need all the info, and experience you all can spare....Thanks a lot!!!
And hey, if this "other member" and his non-underdrive, light weight pulley, wants to tell us how well it works out, im sure some ppl will want it, as long as it doesnt mess stuff up. When they get it working, ask em' to post it up!

When you trip the SES light for missfire it takes it back to the default map for fuel and air if I'm not mistaken. If you are not running amps and tons of crap off your electrical look into the underdrive pullies. I'm not sure UR is even selling pully kits for the car anymore. Do a search over on the club 3g boards www.neweclipse.org

Wes

Well, I did a search on the club 3g boards about these pullies in question. nothing I could find on them. I will contact the company and ask about the underdrive rate belt sizes and weight diff from a standard crank pully.

Wes

Thanks for all your input...does anyone know what the HP gains will really be? Closer to 5 or 28?
Thanks!

I thought our Crank pully actually had a magnet or something similar on it, - called "the crank position sensor" and from what I have gleamed from the service manual. the ECU uses this pretty extensivley in it's computations for timing advance, a/f and transmision features.
I dont thing it would be much to your advantage in changing it. Better to get CIA, Headers, cat back, etc... the stuff proven to produce more HP vs problems.

You are correct. The UR pully duplicates the sensor there was a problem with rubbing that was throwing off the sensor causing a detect missfire.

Wes