This is acutally a two part newb question.

1 - what is the stock boost of the MCS?

2- when you change the pulley 15,17,etc % how does that relate or equate to boost pressure?

This is the first supercharged car for me so I am a total newb to this.

 

stock pulley produces 10.5 lbs of boost
15% pulley raises it to 14.5 lbs of boost
I forget the others

 

19% pulley and I run at 18.5 psi max at WOT in 4th-5th and 6th.

 

19% Pulley and I get 15, maybe 16 in 2nd and third. Seems kinda low, but I blame it on hotter weather.

 

Mine produces 14.5 psi with a 15%