I have the stock 6# pulleys right now, what size pulley do I need to make about 8-9# of boost? how much power would you guess it would add? thanks

 

I have a 2.95" pulley. The stock size is 3.33 I believe. Its new and never used. I'll take $50 for it.

 

Boost and the hp depend a lot on your flow and over system setup. A really rough estimate is something like 20rwhp per lb of boost, but don't hold me to that number.

For 9-10#, I would think it will probably need something like a 3.125" sc pulley. WIth the increase in boost you will need to make sure you put in more fuel. If it is a stock motor, I will highly suggest making sure the car is dyno tuned and maybe add in an aftercooler or something in that line.

The new 2.95" pulley for $50 is a good price, but may give you a lot more boost than you are looking for.

 

I have a vortech aftercooler, walbro high volume fuel pump. My s-trim only puts out 4 or 5# right now because of 4200 ft elevation. I also have hard intake pipe and headers and exhaust. Does anyone know how much boost the 2.95" pulley makes on the s-trim??

 

ttt

 

FWIW I had a set up and altitude very similar to yours, 3.125 x 7" pulley on the S Trim made around 11psi of boost on the stock engine.

Hope that helps

LWM

 

LMW...did you see a big gain in power with the 11psi boost compared to stock s-trim boost?

 

Huge difference

When you pulley up, the boost comes on sooner and so you notice it more. Lots more torque in the sweet spot of the power band ... 4,000 rpm

Hope this helps

LWM

 

how many miles did your LT1 last before it blew up on 11psi? thanks for the help

 

It never did blow. I always ran good gas + Xylene and religiously checked the scanmaster for any hint of detonation.

I finally rebuilt it after 15,000 miles to increase the displacement to 383.

No visible damage to the engine at all.

Hope this helps

LWM

 

thanks for the info .. I think I will try that 11psi setup that you were running. thanks again