I installed a Hallman Pro RX manual boost controller on my stock twins, but it doesn't increase boost. I am using the light spring, and even with the **** tightened all the way, I can only get about .45 kg/cm2 on the PFC. Also, I have not been able to get boost from the primary turbo, maybe a pound or two. I have checked the precontrol rod, and the door is closed, and I have also checked the CCA, and it seems to operate as it should. I don't know if the no primary boost problem is related to the boost controller not affecting boost or not. I have searched, and have read many of the posts, but a lot of the threads end before a solution was mentioned. Thanks

 

Why not just increase your boost settings on the PFC? If the PFC setting is low, it may be adjusting for the MBC.

A frequent culprit for no primary boost is a bad check valve.

 

if you are only boosting 1 or 2 psi on primary then u definately have a leak. the wastegate is 7psi with the pils removed and no bc so u shoukd never be below 7. even the .45 kc/cm2 is lower than wastegate. did u boost fine before mbc install?

 

@ adam c: Well when I installed the mbc, I turned up the settings on the PFC to 1.00 and the max % duty, I think 90. But I still can't get more boost. Also, I just installed Dale Clark's check valves, so I know those aren't bad.
@ sideo: No before the mbc, i still only got about 9psi on my mechanical boost gauge. I still have to prespool pill installed, but removed the wategate pill, when I put in the mbc. How would the leak only affect the primary turbo? I still get about 9 or so pounds on the secondary.
The strange thing is, when I living in Cali earlier this year I was getting about 12 psi on the secondary, but still low, or no primary boost. But once I moved to a higher elevation, I haven't been able to get 12 psi ever.

 

No ideas? I have changed the turbo control solenoid in the rack, could the one on the ACV be the problem?

 

I suggest that you remove the MBC and use the pfc to control boost. If still no boost, check your vacuum chamber for leaks.

 

Remove the MBC as others have already suggested. You should see 7psi on both the primary and secondary without the pill in the wastegate line.

Sounds like your primary turbo might be on it's way out, which is why you're seeing little boost < 4.5k rpm and only 6-7psi > 4.5k rpm. I don't think the secondary turbo is able to make more than that at high rpms alone...