Boost Guage Install
 

I have an 04 GT, Im trying to figure out where to put the boost guage tube. I tried putting it on a vacuum line going to the TB, but it seems to always be reading vacuum and never any boost. I have not been able to drive the car to see if that changes. Its weird there is two vacuum lines going to the same hole on the TB and I followed that back about a foot and t'ed into the hose. Is that not right?

I don't know if it makes any difference but the car is cold while trying this

What kind of SC are you running? And I believe you won't see any boost unless you have a load on the engine. Maybe some of the other guys would know for sure but I don't think you would see boost until you mashed the gas while driving and that you wouldn't see any if just revving the motor.

Its an ATI P1-SC. The load things makes a lot of sense and answers my question perfectly if thats why its not showing Pressure. Still have to wait til this sh..ty weather stops. Thanks for the post.

Yep, you do not see boost till under load. And with your supercharger, you will not see full boost till whatever your shift point is.

what side of the throttle body is teh vacuum line you are talking about? You have to tap into a vacuum line that is after the throttle blade (intake side), just FYI

I agree. The closer you can get the vacuum feed to the lower half of the intake, the more accurate the readings. Don't use the TB hookup. At least find some vacuum feed off of the manifold and T into that.