Upgraded SN-93 max speed

Hi all,
Ive been running my upgraded SN-93 for a while now, getting about 8psi of boost from it at 5800rpm (38,500 blower rpm). I bought it from a guy who said it would produce 12psi, but all I get is 8psi as measured in the plenum. I would like to achieve 10-12psi, but in order to do so I think Im going to have to increase the speed of the blower, anyone done this? What sort of speed can these go up to?
Phil

Don't take it too much over 40K or it won't like you....

F=MA

Hi,
thanks for that, will keep it as it is then, as the next available pulley would take it above 40,000 rpm,
Phil

SN93 Impeller upgraded or not does nothing after 38k RPM anyways so don't over spin it.