Why won't my car do above 23PSI?
 

My car just will not do above 23 psi no matter what,
I'm running a hallman pro rx mbc, even if i turn it up completely, it still does 23 psi,

boost leak test brought zero leaks, and yes throttle was open while doing the test,
it holds 30psi properly, takes like 10 minutes to go to 29psi

Please help?

how is your vacuum line to your waste gate set up?

The BOV.

Are you running an IWG? Check preload. Any exhaust leaks?

Are you sure it's not the fuel pressure going to the BOV? :shoot:

The other common problem with lack of boost is a leak at the exhaust manifold.

They can warp over time, break the stud at the end and then leak.

Or if it's an aftermarket one, they warp AND crack.

Or not enough preload on the WG flapper.

Or the MBC is set up wrong.

take the vacuum hose off the waste gate.
take down the road and see what it will boost.

be very quick to let of the gas if it swings past the 25 mark.

this will tell you if it is the turbo/manifold, or your boost control

if its bad... should be able to hear it.

start it up when its cold and put your hand down around all the turbo and down pipe.
feel for leaks.

careful, it gets hot quick.

remove the gasket and examine it for discolouration.