can someone tell me the diameter of the 7lb comptech pulley. help appreciated

 

4" I believe.

 

3.5" is the correct size. Sorry Aus.

 

3.5" is 9lbs. I am pretty sure 4" is 7lbs.

 

Well, if I'm wrong, I'm sorry. I just removed a 3.5" pulley from Black Nugget's car and it was presumed to be a 7lb pulley. I'm not sure how to figure this out then...

 

Not saying you are wrong, but if his 3.25" pulley was 9.75 psi, according to the thread he posted the results on.

https://www.s2ki.com/forums/index.php?showtopic=305657

 

Right, but it was calculated to be 12psi. Also, it was very humid outside the few days the tuner had his car. If there's one thing I keep telling BN to get, its a boost gauge. I might try and get a new reading on his boost pressure this weekend, if I can get a temporary gauge to use...

Anyway, that's off subject a bit.

 

So the 9.75 psi was based on a calculation?

If the 3.25" pulley is 12 psi, I would think his numbers would have been a bit higher.

 

No, the 9.75 was true boost during tuning. 12psi was the expected boost pressure with the 3.25" pulley.

We were expecting a bit higher numbers as well.

 

All I know is I was using a 4" pulley and getting 7psi with AC.