-30hg/in vacuum and only 1 psi boost
 

hello all!
so just recently sent my Vortech SC back to their factory to rebuild the v3 into the oil fed v2 unit. after 2 months of waiting and finally i got it back. So the shop installed my supercharger and put it all back together, keeping the same pulley size and all that. However...
The car is not getting power or much boost at all. according to Torque app, during idle i get about -27hg/in and lift off i get -31. Seems quite low for vacuum as before my car was -20 range. and WOT i get about 1 pound of boost. and the car feels like naturally aspirated power level. Before I was seeing about 9 pounds of boost with my 3.48 pulley. Same tune, same setup, and I am very confused. So the shop pressurized the system and we are sure there is no leak anywhere.

i am trying to diagnose and trace down the problem. So, What could cause the symptom of a high number in vacuum and almost no boost? :thanks:

I know they have a cw and a ccw what's the odds they sent you the wrong one and its spinning backwards. Is their a way they could of routed the belt backwards? Bypass line leaking??? good luck

Are you reading the pressure from the ecu or an aftermarket sensor/gauge

If from the ecu, 27 inches of vacuum is very high for a warm idle, you should be seeing around 20

Correct map sensor installed? Does pressure rise at all with rpm during a pull? Boost leak test done? Bypass valve stuck open?

What gauge are you getting this -30 reading from? My guess is that the calibration is off on it.

Try resetting the Torque app. At times the calibration becomes funky within the app. Some days I'll hit 4psi in boost and some days it will be fine at 9psi. I'm on the 3.48 pulley.

My guess is calibration as well. You can't pull -31 in/hg. -30 in/mg is absolute vacuum...

either way something must be wrong if it feels that slow...