not tryin to be a noob but what realy is the point... any power increase?? or does it just make your pump spin faster?? or............ just totaly not worth it?

It spins the pump SLOWER, supposedly saving power. I run one, and it'* not fun sometimes. I believe a 10% underdrive is too much for a daily driver in almost any climate. I'd prefer a 5%.

It may cause you to have to change thermostats a couple times a year. And dyno'* are historically unrepeatable at the low HP figures this thing claims to save.

Mr Bill, do i remember you saying that the stock WP does something at WOT??? Cavate or something like that??

I dont know if i am a one case person, but i gain a solid .2 in the quarter after installing mine. From before i installed it (16.0) to now (15.7-15.8 ) and also picked up a solid 2MPH in the quarter. And that is with several times testing before and after (about 15 each atleast). Could be a freak thing but my car pulls alot better from say 60 on. And it made a huge difference on the way top end say from 95-shutoff. BUT... on the bonne'* you have to modify the motor mount and it does take a while to get it enough for the pulley to fit. Got to go for now but if you want any info pm me.

TJ, the 3hp that pulley could have gained you would possibly equate to a .05 second improvement if that.

No underdrive pulley ever gained anyone a fraction of a tenth. Your skill at launching and driving the car is what changed.

Do H body'd L27'* need to modify their motor mounts as well?

Ditto on the time taken off. May have a been a few things, it would take a full underdrive set to gain .1-.2 off.

Will, i thought and thought about that after it happened. And compared all my slips and what not. All my launches were 2.3. So it wasnt in the launch. Also if i launch better then and my 60'* were lower then that would actually lower my trap? correct? The only other thing i thought was i have a 1995 and it shifts at 6000. So maybe the fact that it was shifting at that before it was actually hurting me. Then that extra 3 or so whp over the longation of say 600 rpms maybe that did it. I am not sure. But i know i had a solid 15-20 passes before the swap and they were all 16.0-16.1ish. Then after the swap i hit a lot of 15.8'* and a 15.7. Also i have talked to people on the grand prix club and everyone except for maybe 1-2 said they gained .1. They all seemed to gain a solid tenth with the WP underdrive. The alternator one nobody seemed to get a real noticable gain from. I dont dissagree with you about the 3whp not giving a seeable gain. But i would have to say mine did.

GP'* have different gearing, weigh less, and have different PCM'*. And anyone'* claim can be cut in half nine times out of ten. There'* no way a simple WP underdrive pulley would give you a noticable gain.

Track conditions, barometric pressure, relative humidity, temperature, and heatsoak will affect you that much or more. You cannot possibly begin to characterize and prove such a small gain without 20 dyno pulls before and after on the same day, same conditions, etc. Normal variance from dyno pull to dyno pull is more than 3hp.

Yea i agree with the weather and track conditions. I dont know. Maybe it is just a freak thing. Just as i thought abotu my times and they were over the duration of about 2 months. All different days and some night and soem day and everything. And to this day with the same 60'* i am still atleast trapping 3 mph more. All my runs before the pulley were 86 and one was 87.0 and now they are all 89.5 to 89.7. I dont know. I have to say that i have to agree with you that it wouldnt make a difference at the track but.... lol

I would like to give that TB of yours a try at the track. One of these nights when you are sitting there thinking of what to do (doesnt happen often i bet) . Say to yourself TJ needs a nice improvement in throttle reponse and go out there and do up a TB. kinda a Quote from gone in 60 seconds..... Have yourself a good time and make a little money It has to be a TB from a 97 grand prix or i think 95/96 bonneville, it has to have the extra vacumm for the tranny.