5c worth of brass, worth its weight in gold !!

[BigDatto]

Hi Y'all,

I recently installed a blitz EBC (thx FAT32) and a larger intercooler (thx Amadeo) and all was good - until I wound the boost up to 9psi. As soon as the tacho hit 4500rpm, cough, cough - hmmm sounds like overfuelling. Fast forward two weeks, I'm cleaning out the garage thinking "yeah, I should keep that tee piece left over from the EBC installation, one day I'll need it - hello what's this little brass restrictor in the vac hose ??". I re-fitted the brass restrictor just b4 the W/G actuator and no more cough/misfire. No noticeable change to wastegate creep either !!

So if anyone else has experienced the same when upping boost, keep that tiny brass restrictor - It's worth its weight in gold !

I hope this info helps

[Redbaboon]

Thanx BigDatto,'

I'll be doing the same soon - you help might save me some headaches!

[JimX]

So what does the restrictor actually do to help it stop losing power? Did the boost read the same before and after?

[Guest RedLineGTR]

Thanks for the heads up

[walkoau]

wouldnt you be running lower boost now with the restrictor in?

[Airzone]

He's got it restricting flow to the wastegate, not the engine.

[BigDatto]

10-4 Airzone.

The factory fitted restrictor 'slows' airflow to the wastegate actuator, reducing wastegate creep and helping the turbo to spool up faster, what it doesn't do is increase boost. It does (in my case anyhow) appear to prevent overfuelling. Maybe someone with expertise in this field could explain the physics of it. I posted this finding in the hope it might help others with similar issues, and those who are sick to death of pulling out spark plugs & gapping them down another poofteenth of a bee's dick !! ( & haven't we all been down THAT road...).

[walkoau]

im running 10psi boost and still have the brass restrictor in place, but since i got my full 3'' exhaust on its overfueling heaps???????

time for me to get fuel/air controler.

[BOOSTD]

Boost has been reduced(maybe only at the miss point) and fuel mixture is leaner.......only thing thats makes sense.....

[MegaGTS4]

The restrictor delays the pressure signal from entering the wastegate, which spools up the turbo faster, which means more boost at lower RPM, as BigDatto posted

Turbosmart have pattented this theroy and they call it the gated boost control valve (GBCV).

Maybe nissan have been using restrictors on its factory turbos because some of the wastegate lines can be very long by the time they pass the boost control solenoid and then make there way to the plenum, or Maybe the factory restrictor is for another reason.

MEGA