Low boost simple solution?

[BaysideGTR]

Here is a noob question. I have a stalk BNR32 GTR. It's boost runs low. Like max .3 bar. I am about to take it in a week to get a bunch of work done including sorting out the low boost issue.

What I am wondering; is it possible the previous owner "turned it down" somehow? There is no aftermarket boost controller. So I don't know if that would even be possible.

It's vague, but is there some quick easy checks that I could do myself to circumvent the issue? I checked the pipes for leaks etc with soap and had no luck, might be because there is a vacuum formed... dunno I'm stumped.

[Skym]

Check for crack in vacuum hose to stock MAP sensor (for stock boost gauge) that's mounted on engine bay side of firewall, just infront of driver.

Boost level shouldn't go below the wastegate spring psi. When internal wastegate actuator spring wears out the boost level can drop below the lowest psi in the range. Range should be 9.94psi-11.36psi. To check wastegate spring psi you pull the internal wastegate actuators off turbo's and fit a vacuum hose to them with a mechanical boost gauge T'd in and apply compressed air to vacuum hose. When internal wastegate actuator arm moves, note at what psi on boost gauge. Can do this while the internal wastegate actuators are on engine, but get different readings on boost gauge.

The other would be a intake manifold airleak (blown stock gaskets) which is common on GTS, GTR when boost levels are turned up (sometimes can happen due to age). There's metal intake gasket kits you can buy from tuners in Japan (Tomei, etc) that solve this problem.

[amnash]

cant install a boost controller to lower the boost. only to increase it.

[Skym]

It shouldn't go any lower than internal wastegate spring psi. The lowest psi in the range mentioned above is the lowest psi before internal wastegate actuator should be changed. But for boost level to go to 0.3bar, has to be intake manifold leak, intake piping leak next to intercooler (intake hose joiner has popped off) or vacuum hose from MAP sensor (for stock boost gauge) to intake manifold is cracked.

[Frankyy]

I would start with an aftermarket gauge for the vacuum and will also do boost, the oem gtr boost gauge might hace a leak in the line and moght not be accurate, and also remove the intake piping and check your fins on the compressor side to make sure the turbo fins are still good, and while your there check for any shaft play and spin the wheel see if it's smooth.

Can you hear the turbo spooling at all?

Did it boost fine before? Can you feel the car not boosting past .3bar? Or your going off what the gauge says?