Underdrive Pulley

[rpm9000]

I purchased an underdrive pulley from Parts Rack. I was skeptical because I have heard some people say that they are a waste of money and some say that they saw a rwhp increase. I dynoed my car last Sunday and the result was 480 rwhp. I installed the underdrive pulley and did another dyno run today and the results were 490 rwhp. The first 2 runs were back to back and they were both 490 rwhp. We let it cool down and made one more pull and it was 498 rwhp. I am very happy with these numbers from my old Gen.1 with Greg Good Econoport heads.
You really can't feel 10 hp in the seat of your pants but every little bit adds up.

 

[345s-bspinnin]

Great improvement and great numbers out of that Gen I, especially out of that mild cam

 

[FLATOUT]

Damn your car is making great power! Great to hear I'm looking to throw one on my car soon as well.

 

[NVMYVPR]

I am looking to do a similar set up on my 96 RT-10 in the near future. Are the 65mm TB's necessary?

 

[mralbuquerque]

There you have it....

 

[rpm9000]

According to Greg the larger throttlebodies should help. The stock Gen.1 throttle bodies are 58mm. I didn't dyno the car before putting the 65mm throttlebodies on it so I can't say how much difference they make. You have to open up the manifold to match up with the larger throttlebodies.