Hey guys -

I bought the kit used some time ago, so since I'm seeing 6psi, I assume that it is a 6# pulley on the blower. This is what they came with stock, correct?

Since, I have rebuilt with lower compression (9.5:1) and wanted to up the boost. What are my options as far as pulleys to increase boost and where is a good place to purchase?

Thanks.

 

I would just get your pull from procharger they seemed reasonable on price for all the ones I ordered.

 

Here's the problem. There's no such thing as a 6# pulley. There is a pulley that makes 6# on YOUR engine. There are probably 20 different pulleys that can increase or decrease your boost. ProCharger measures the diameter of the pulleys where the belt rides on top of the ribs, not the face of the pulley where the shoulders are. Measure both your crank pulley and blower pulley and I can try to help you from there. (The blower pulley MAY have the size stamped into the face of it.)

 

...exactly what the Procharger tech said yesterday. I will try to get it off this weekend.

I assume this can be done with the head unit on the car?

 

im in t he same boat. rebuilt forged 383 w/ a p600b.

any info will be appreciated

 

I had run a p600b on a 383 97ss. I moved to the smallest pulley. I rolled the key on the input shaft. The input shaft on a p600b is small. Not much key section (1/16" sq). The D series and up has a larger 7/8" shaft and two (2) keys. Much better load transmission. I would not run the smallest pulley (a 12 psi notation). B.

 

the stock crank pulley for the blower is 7" .. i think ..someone correct me if thats not right

Im running a 8rib 2.75" blower pully with the stock crank pulley ...i was told this should make close to 12psi on a stock engine .... i see about 8-9psi @ 6000rpm on my 9.5:1cr 355ci

 

remember PSI is resistance, you need to be concerned about how fast the blower is spinning not how much boost your making... and a p600B isnt moving crap for air.... step it up to a D1SC, the p600B,P1SC, D1SC, and the F1A share the same blower bracket. what i do know and i dont know if it relates to the P600B because im not sure of the impeller max speed on a p600B, but with a P1SC with stock size crank pully the smallest pulley you can run safely is a 3.4 inch pulley. there is actualy a calculator you can use online somewhere that you put in your crank size, max impeller speed and it will poop out a pulley size for ya

 

You can't necessarily say that 3.4" in the smallest you can run. Max engine RPM is also a critical factor in calculation impeller speed. If your max engine RPM is only 5500 or 6000 RPM, you can get away with a smaller blower pulley than if you're twisting the engine to 8000 rpm. 3.4" was the smallest that ATI would sell though, but there are custome fabricators out there.

 

6200 rpm is max on the 3.4 and the P1SC... i know this because my tuner (i wasnt there) spun the car to 7K and greneded my new P1SC... he didnt offer to fix it even after i told him not to rev it past 6200... hes no longer my tuner.

 

Is the following formula correct?

Impeller Speed = (crank pulley/blower pulley)(Internal step up of blower)(Engine RPM)

I'm running the 2.65'' blower pulley with 7'' crank pulley and shifting at 6500. The blower step up is 3.05:1, so this should put the blower speed at ~52000 rpms, correct? This is 'safe' since the 600B maxes at 60,000, correct?

Also, should the P1SC grenade at 7K if the above equation is correct? The step up on that model is 4.10:1. That would put the blower at ~59000 rpms at 7K and it is rated at 62,000 rpms.

 

With the 7" bottom pulley the smallest pulley I could run on my 600b was a 2.55"- and that was set-up to have the motor turning no more than 6500.

When doing this you create a few problems- the small pulley size doesn't provide much grip for the belt and you have to really crank down your tensioner to prevent the belt from slipping. This just adds additional strain to everything and you will burn up your blower bearings faster too. You also don't want to turn the blower at max rpm either since it starts to cavitate the air and doesn't do you any good.

I was in the same boat you are- ideally you should step up to a bigger blower but prol money is a huge factor. I didn't have the 3k to buy a new blower so I did what I could to get by.

I had a 2.55" pulley and would shy away from going that small- it was really hard to get it set-up right. You will have to get a smaller belt as well- Try to get a belt that allows about 75% driven pulley coverage but isn't so close that the belt will run the danger of coming in contact with itself on higher rpms when it stretches.

Also- when pulling the pulley off grab a torch and just slowly heat the pulley until you can pull it off with a thick gloved hand. If you use a puller on it you run the risk of damaging the pulley and or possibly the bearings in the blower itself. Reinstallation is the opposite- heat the pulley until it will slide on the shaft.

Hope that helps-