Inconsistent Boost With Stock Turbos and Boost Restrictor Removed

[Nizzy]

Hey there,

I've searched but cannot find that answers I'm really looking for, for my situation.

 

I've had my R32 GTR for about three weeks now, it's mainly stock except for an exhaust and apexi intakes. I removed the boost restrictor in the line to the boost solenoid. The issue is, some times it's great and gives me about 14psi of boost, and sometimes it gives what feels like stock or less than stock boost. It can do this on the same drive, with nothing apparent changing, it just seems totally random if it will be the 14psi or the 7psi-10psi.

 

Has anyone had experience with this or have an idea what could be causing the inconsistency?

 

Thanks heaps in advance for the help, this forum has been a huge help already 🙏

[Duncan]

I guess there are lots of old parts that could cause that these days including the wastegates themselves.

However, first question, is the car running smoothly when it only makes 7psi instead of 14, or is there some hesitation as well? A missfire as the car comes on boost is quite common and could limit the boost it makes

BTW, well done finding a mostly stock GTR after all this time!

[Nizzy]

6 hours ago, Duncan said:

I guess there are lots of old parts that could cause that these days including the wastegates themselves.

However, first question, is the car running smoothly when it only makes 7psi instead of 14, or is there some hesitation as well? A missfire as the car comes on boost is quite common and could limit the boost it makes

BTW, well done finding a mostly stock GTR after all this time!

I'll have a look into the waste gates, thanks mate 

 

It runs completely smooth regardless of how much boost it decides to make, on the 14 psi it feels great actually

 

Thanks mate! Took a while to find the right one but I got there. Thanks for your reply 

[joshuaho96]

13 hours ago, Nizzy said:

Hey there,

I've searched but cannot find that answers I'm really looking for, for my situation.

 

I've had my R32 GTR for about three weeks now, it's mainly stock except for an exhaust and apexi intakes. I removed the boost restrictor in the line to the boost solenoid. The issue is, some times it's great and gives me about 14psi of boost, and sometimes it gives what feels like stock or less than stock boost. It can do this on the same drive, with nothing apparent changing, it just seems totally random if it will be the 14psi or the 7psi-10psi.

 

Has anyone had experience with this or have an idea what could be causing the inconsistency?

 

Thanks heaps in advance for the help, this forum has been a huge help already 🙏

Do some ECU logging. Consult cable + Nissan Data Scan 1. Try to record a 14 psi pull then a 7-10 psi pull. Make sure you record airflow + airflow RH, throttle, RPM, injector, ignition timing, and wastegate solenoid. If the solenoid indicates it's on in both cases and you aren't on knock maps then my first suspicion is the wiring to the solenoid might be intermittent. Next step from there is to unplug the ECU, get some long wires and verify the wiring from the ECU to the solenoid maintains solid contact/low resistance, jiggle the wires while probing to see if it drops out at all.

If all of that checks out you should try capping the plenum to wastegate hose, then test with 3/5/7/10 psi regulated pressure and figure out the minimum pressure needed to barely move the wastegate actuator, then how much is needed to really get it to swing open. The R32 engine manual has a more specific spec for these things but if it's like 8-9 psi to really get it to swing open then it's fine. You can try putting as much as 20 psi into the wastegate actuators to see if it opens smoothly and doesn't make weird noises/rattles.

If none of those things are conclusive try removing the intake piping enough to look at both turbo inlets. Or the turbo outlets in the exhaust if you prefer removing the down pipe and turbo outlets. Make sure nothing is damaged, no shaft play, etc.

If none of that figures it out then I dunno. Post back and I can noodle on this more.