So I just installed my boost gauge and took her on a spin. The first thing I noticed was that it was still producing about 13-18 inHg of vacuum while I'm in gear, driving at around 2000rpm. At around 2500 rpm it goes up to about 5-10, but if I stay at the same rpm it'll move back down to around 13-18. As I get to 3000rpm it slowly becomes zero, then at around 5-8 (never quite 10). Some times it shows I'm getting boost, then gradually goes back down to zero. I'm only getting 10 when I'm about 3500-4200 rpm. After I go past 4500rpm the boost is fine.

 

TCA door might be slightly open robbing boost from Primary

 

Where is the TCA door located? Pictures would help a lot. Thanks!

 

Vacuum is determined to a great extent by how far open the throttle it, rather than RPM. You accelerate by opening up the throttle, which allows more air in, which lowers the vacuum. As you reach your speed/rpm you close the throttle which will increase your vacuum. Depending where you are in the RPM band and what your road speed is, your vacuum may or may not go back to its previous level at that increased speed.

Boost under partial throttle depends on too many things to predict or describe.

Put the car around 2k rpm in third, make sure you have open straight road in front of you and then go WOT (wide open throttle). Do you see 10 lbs of boost before 4500rpm? Do you see the 10-8-10 (or similar) transition going through 4500 RPM as you accelerate at WOT?

If so then you are fine. If not, then what boost pattern are you seeing?

-b

 

Oh. I thought boost was dependant on your RPMs because in at 3000rpm the primary turbo kicks in reguardless of what throttle pos. you should get 10lbs of boost no?