are there any distinctive marks or numbers that seperate a 7lb pulley from
that of a 9lb pulley??? measurements??? When I bought the car in 2004, the previous owner said that he used the stock pulley... I have seen the boost gauge spike to 10psi before...

 

When you seen it spike to 10psi , was it just as you were letting off the gas ?

 

yes there r numbers on the pulley to represent how many teeth they are......

 

^ +Mf1.. Tell us the teeth and we will tell you what psi pulley you have..

 

sorry to bring this back, im having the same problem. i searched and got many different answers i just ordered the "9psi set" from a vendor here and it came with 3 pulleys, the third being the one you need to remove the flange from on the back of the blower a 28tooth. i thought you only have to change the front 2? the numbers on the puleys are 25 / 40. i called procharger prior to ordering directly and asked what tooth count all the pulley sets were and here is the anwser i got from their tech line (7 psi - 27/38) (9 psi - 26/39) (11psi 25/40) when i search nothing mathes one example https://my350z.com/forum/turbos-nitr...lley-sets.html any help would be good thanks

 

Yes, you only change the front 2(big one right in front of the fan/pulley to the right of it), hence the reason the procharger tech told you only 2 tooth counts. If there were a third trust me id know, and the procharger tech prob would have told you ( i say prob cause they arent all that great)

 

I figured this would be the best place for this info...

By combining advanced supercharger transmission design with the highest quality oil, SC ProChargers produce a larger net power gain because they run cooler and consume less power than comparable oil-fed designs. SC ProChargers also feature an internal step-up ratio of 4.10:1 for improved belt tracking and traction, and maximum low-rpm boost and power.

http://www.procharger.com/models.shtml


I found this pulley info and their formula in the ProCharger manual…

Maximum impeller speed should not exceed the redline of 80,000 RPM for the C-2. Maximum impeller speed = pulley diameter rotation of the serpentine belt, multiplied by tooth ratio of the main cog belt, multiplied by tooth ratio of the blower cog belt, multiplied by the ProCharger internal step-up ratio, multiplied by engine rpm at redline. Diameter and tooth ratios for a given belt are defined as the diameter or number of teeth of the drive pulley divided by the diameter or number of teeth of the driven pulley.

All of these ratios are fixed except the main belt ratio. The boost level is varied by changing pulleys N1 & N2. When changing boost level, both N1 & N2 must be changed to avoid changing the required main cog belt length. For a 7-psi level, N1 is 38 teeth and N2 is 27 teeth and a maximum engine speed of 6600 rpm the maximum impeller RPM is 60,856 RPM. For other pulley sizes the impeller RPM is found by using the following equation.

Impeller RPM = (5.75/5.25) x (N1/N2) x (28/22) x 4.7 x engine RPM… or
Impeller RPM = 6.5515 x (N1/N2) x engine RPM

For example>>> 6.5515 x (39/26 = 1.5) x 6600 = 68,791
Another example >>> 6.5515 x (42/24 = 1.75) x 6600 = 75,670

On the ProCharger link they show the Maximum boost for the C-2 at 24psi and the Max Impeller RPM at 80,000. I’m assuming these MAX numbers coincide with one another and only represent max PSI on paper. Obviously we settle on another PSI number with real world variables.

So basically I can’t set my RPM past 6900 using the (42/24 tooth pulley set) and not exceed 80K RPM. Which kind of sucks because I have a 3.9FD setup, damn!
More to think about...


Zquicksilver