boost question

[tcavenger99]

OK i am running a ihi turbo . my boost gauger hits 13psi and Afr is around 11.5 now yet it didn't seem like it was pulling hard enough , so i installed another boost gauger (temp) into the line coming of the turbo compressor . and fed it to the dash . on my main gauger it hits 13 psi (taped into the intake) fine then holds ? , on my other gauger(one of the turbo compressor it reads 5 psi) . i checked my external waste gate and it works fine . any suggestions what is going on . am i hitting 5 or 13 psi ? I have a manual boost controller hooked up as well this is how i am boosting 13.

 

[silvreclips]

What is your wastegate set at? I would probably take the MBC off and run just the wastegate pressure so you know you should be boosting x amount. With the MBC on you dont really know if its raising your boost or not since your not sure if your gauge is accurate. Run both boost gauges off the intake manifold and see what they say. They should match or be very close. I have never seen a gauge off by more than a couple psi.

 

[rstare]

I assume your vac line from your compressor runs to your mbc then to your wastegate. Where did you tap your "temporary" boost gauge into? Before the mbc, or after? If after then there is your problem.
Where exactly did you tap your "actual" boost gauge? Which line off of the intake manifold?
This will help in figuring out.

 

[tcavenger99]

first off the vac line is before the mbc so its a free line from the compressor . and i have my true boost gauger ran off a T in the line going to the bov .

 

[snowborder714]

You shouldn't tap your true boost gauge off of the bov vacuum line. Tap it into the FPS/FPR vacuum line or directly from the intake manifold.

Also, how is your MBC installed? You should have the line running from the wastegate to the side nipple. The bottom nipple should be connected to a boost source (intake manifold, compressor housing, etc.).

Which MBC are you using?