Low Boost

[andrewjstacey]

Hi there,

I recently imported an 89 R32 GTR.

Its fitted with N1 turbos but was only running 6.5psi boost using the standard boost controller, I removed the restrictor in the vacuum hose and now the boost is up to 9psi. This seems low considering most posts etc seem to think that without the restricter it should run 15psi.

I have checked and rechecked all the piping etc looking for any leaks or splits but cant find anything.

Anyone have any ideas as to why its low? Could it be because it has the different turbos and as to how I can remedy it?

Thanks!

[R31Nismoid]

Given it's not factory turbo setup etc, who knows.

Could be sloppy actuators.

[The Dan]

Hi there,

I recently imported an 89 R32 GTR.

Its fitted with N1 turbos but was only running 6.5psi boost using the standard boost controller, I removed the restrictor in the vacuum hose and now the boost is up to 9psi. This seems low considering most posts etc seem to think that without the restricter it should run 15psi.

I have checked and rechecked all the piping etc looking for any leaks or splits but cant find anything.

Anyone have any ideas as to why its low? Could it be because it has the different turbos and as to how I can remedy it?

Thanks!

That's an easy fix. Install a boost controller

[DVS JEZ]

^^^what he said

are you using an aftermarket gauge, if you are already check the boost line going to it, make sure its not kinked or crushed blocked etc etc

[andrewjstacey]

Not a faulty boost gauge have checked there as well.

I tried blocking off both lines going to the wastegates as a test, still the same, I thought that in theory that would mean they dont open so would max out turbos? Or have I got it horribly wrong?

[MrStabby]

Not a faulty boost gauge have checked there as well.

I tried blocking off both lines going to the wastegates as a test, still the same, I thought that in theory that would mean they dont open so would max out turbos? Or have I got it horribly wrong?

AFAIK if there's no boost getting to the actuators then yeah boost should keep climbing unless the exhaust pressure on the wastegate flap is enough to overcome the spring in the actuator. If its only getting to 9psi then replace the actuators or tighten them up if they happen to be adjustables.

As an additional check some also fix the wastegates shut (maybe clamps on the actuator rods??) then VERY CAREFULLY run it up to verify it will go past 9psi. Again, the boost should just keep climbing so make sure you back off once its past 9 psi so you dont break something expensive....

Summary - 9psi with disconnected actuator boost signal then more than 9 psi with wastegates fixed shut = stuffed wastegate actuators. Someone will correct me if i'm wrong.....

[ClutchBurndout-:(]

turbotech not turbosmart

thats what ur after, cheaper to, ironic huh

[andrewjstacey]

Thanks for all that, also I've noticed the boost doesnt come on until about 5000rpm and doesnt reach 9psi until close to redline, as this is my first gtr i dont know if thats normal?

[Dose Pipe Sutututu]

try blocking one turbo from the inlet and with the other use an airgun and compress air into it and see if there are any air leaks.. do this with the motor off

[Rolls]

Adjust the actuator rods, could be too tight.

[The Dan]

+1 actuator rods are too loose or the diaphragm is fubar