Technical Information 

Can I just use my stock belt?
Although it is true, you can use your stock belt with our 3.4 Modular and Press-On pulleys, you will not be doing your car justice. We highly recommend the Goodyear Gatorback® belt.      Click here for details.


Direct from THRASHER__
all Supercharger Gatorback® belts are $21.99 ea.

*Technical application for pulley size is a balance between low RPM torque and upper RPM horsepower.  With decreasing blower pulley size, the blower spins faster for a given engine speed.  Dyno tests will show that increasing the blower speed to engine speed ratio (i.e. using a smaller blower pulley) will effectively shift the power band of the engine toward the lower RPM.  Lower RPM torque will increase but upper RPM horsepower will ultimately suffer due to the intense heat generated by the relatively low adiabatic efficiency of the roots type blower. If you DO NOT plan to make any other performance modifications to avoid the detonation caused by a higher temperature intake charge, we recommend you stick with the 3.4" pulley.

*THE SOLUTION? If you want to install a 3.25 or smaller pulley, cool it back down and get maximum throttle response with the THRASHER Cold Air Intake Kit and colder sparkplugs (2 heat ranges colder). With these FWD vehicles being traction limited (they'll light the tires at ease as you racers well know!) the pulley must be correctly sized to balance the low speed torque and upper RPM horsepower. THRASHER also highly recommends either headers, ported and polished exhaust manifolds, or THRASHER Intercooler.


Our 100% virgin steel THRASHER pulley is polished &
powder coated black.

How will it feel?
Let us know when you catch your breath!  

Hey, don't just take our word for it! You must experience this for yourself! Throttle response is much improved even with the stock factory torque converter and final drive ratio.  Torque increases are evident at all RPM ranges and throttle positions - even light throttle applications are noticeably quicker. Given max stock boost levels of approximately 8 psi at the shift points, this pulley will give approximately a 40% increase to 11+ psi. Of course, maximum boost levels will vary somewhat due to air density, temperature and rpm.
For dyno data, CLICK HERE and see the results!

 - Typical gains for the 3.4”  pulley -- 25-30 HP
 - Typical gains for the 3.25” pulley
-- 30+ HP
 - Typical gains for the 3.0”  pulley
-- 35+ HP

Why Should You Choose THRASHER?

Because we are the original and we established the Industry Standard for these Supercharger Pulleys AND the Pulley Removal Tool, that's why. This is where it all started.

THRASHER Engineered Performance pioneered the process for removing and installing these supercharger pulleys unharmed as soon as these cars came to market! That's right ... we had the guts to take on the challenge of removing the stock, press fit pulley when others wouldn't dare! We perfected the technique and released our pulley removal tool and pulley to the public in January 1997 after extensive testing to ensure ease of use and determination of the perfect sizes for the ideal balance between low end torque and upper RPM horsepower ... all while using 92 octane pump gas*. Accept no imitations!  We are the industry standard.
APPLICATIONS:
- 1997-03 Grand Prix GTP
- 2004-05 Grand Prix GTP
- 2004-05 Grand Prix GTP Comp G
- 1997-04 Regal GS
- 1996-99 Riviera

- 1996-04 Bonneville SSEi
- 1996-04 Park Ave Ultra
- 2004-05 Monte Carlo SS
- 2004-05 Impala SS


CLICK HERE to buy or rent our Pulley Removal Tool!


What gains can I expect over the stock pulley? We realize this is a hot topic but, we don't believe in making predictions. The realistic answer? There are three main contributing factors: climate...ie. weather conditions, air intake temperature, and modifications to the engine, pcm, etc.

Our original pulley design
January 1997 

Shown above is an early production unit from 1997. It's turned on a CNC lathe from a solid steel billet and was gold iridated for corrosion protection. It was determined that increasing boost significantly beyond 11 psi on this Eaton M90 blower was detrimental to performance without an intercooler.
CLICK HERE for a look at the THRASHER Intercooler!

THRASHER Pulley Removal Tool Direct from THRASHER ___$124.95 + S&H

THRASHER Press-On Pulley
sizes: 3.4, *3.25, & *3.0

Direct from THRASHER ___$ 59.95 + S&H
 
Still have Questions? ... We'll answer them. Click here.