About 2 months ago, I installed an autometer boost gauge and everything was fine (boost max was about 19psi).

2 weeks ago, I installed a Hallman Pro MBC (heavy spring) and everything was fine (had my boost tuned to 20psi and less taper).

Yesterday, I noticed that the car will not boost beyond 16psi. Thought it might be the heat (around 100 degrees out). Tested it this morning and about the same.

I am getting a boost leak tester, however, could it be something else? Boost gauge bad? Hallman MBC?

The car still seems to have good power. BTW - I have a K&N drop in filter and a Works ABE. Thanks in advance

 

Did you try turning your boost controller up? Also, the power feels the same?

 

Cant drop to 16 unless somethin happened. Does it max out at 16psi in every gear from a low rpm roll-on?

 

When I originally installed the MBC, I did have to turn it up to get to 20psi. I have not turned it up anymore today because of the fear that if it is an issue with the gauge, I would be turning my boost above 20 psi (stock turbo, 91 octane).

My butt "dyno" says the car feels pretty good...almost to the point where I wouldn't have noticed. Just not sure how good my butt dyno is....

 

Minimum setting gives 20psi. Cant say I've ever heard of that even on a stiff spring.

 

I did about 4 pulls in 2nd, 3rd and 4th gear. It might have hit 17 psi a couple times but the consistent max pressure on the gauge was 16psi with a slight taper to 15psi

 

No, I actually had to turn the adjustment knob on the MBC quite a few turns to get it to 20 PSI when I originally installed it.

I meant that I have not turned it today in my testing. Again, don't want to be over boosting if it is a gauge issue.

 

You might of got some crap stuck inside the Hallman. Unscrew the barb fitting off the bottom and check the ball and seat.