Boost Creep fixed with using Greddy BOV

[DSM4me44]

I recently posted a thread entitled "rethinking my 14b upgrade". Well after porting both my turbo and o2 housing i was upset because i still was gettin bad boost creep. In second gear i would boost 12 psi and it would climb to 18 and then in 3rd it would start at 18 and climb. Well i have been trying different things and today i fixed the boost creep. I don't understand why. I own a Greddy Type S bov and what i did was T the hose after the manual boost controller and connect it to the lower nipple on the greddy bov. Can anyone explain why this has corrected my boost creep and made it so i can actually control my boost level once again.

 

[CanadianTSi]

The BOV is now leaking out the air, the turbo is still creeping.

 

[DSM4me44]

Yea, but if i set it at say 16 psi and it was leaking, wouldn't it start at 16 and drop? Before i put the MBC on and after i connected the lower nipple, i would run 10psi and when it shift(automatic) it would hit 12 and then rest back at 10. I have it set at 14 and it hits 16 when i shift then rests at 14. Before i connected the nipple, i couldn't even stay below 15 psi in 2nd and in 3rd i coudn't stay lower then 18 and it would just creep higher and higher.

 

[CanadianTSi]

THe turbo can produce more than 16psi so no it wouldn't drop.

Your putting alot of extra stress on the turbo this way because your making it work alot harder to maintain 16psi.

Pull off the turbo and port it correctly to cure your boost creep.

 

[kenamond]

A BOV can't do anything to cause boost creep and isn't intended to fix it either. It's strictly for surge protection.

Make sure your wastegate is working. Disconnect the wastegate actuator arm and do two tests:

1) See if you can freely open the flapper with your fingers. If you can't open it, then you need to fix this.
2) If the flapper opens easily, do a test run with the wastegate arm still disconnected and see if you get more than a few psi of boost. If you do, then you need to consider either improved porting of the wastegate passage or reverting to an external wastegate.

If both of these check out, use a vaccuum tester to check the wastegate solenoid to see if it's opening at the proper pressure. If it doesn't open, check for interference of the actuator arm with something (maybe the lower heat shield or your intake pipe). If there is no obvious interference, but the wastegate doesn't open, your solenoid may be bad.

It sounds like you've got a band-aid solution right now by limiting boost via your BOV instead of your wastegate.

 

[gammey4]

When you ported your o2 housing did you port the around wastegate flapper so it can open all the way? Also if you arent running a cat that can cause boost creep issues.

 

[DSM4me44]

I fully ported my turbo and ported so the wastegate flapper can open 90 degrees. I also ported the o2 housing. I have a cat as well.

 

[blackGSX2g]

CanadianTSi is right. I had massive boost creep problems with my 50-trim when I was waiting for my external wastegate. I loosened the screw on my GReddy BOV when I put a new gasket on and it 'fixed' my problem by creating another one. I immediately tightened it back up.

In essence, it creates a boost leak so large that your turbo is having a hard time keeping your intake tract pressurized, so your boost will stay around what you set it to. You will want to tighten that up ASAP.

Did you properly port around the passage to the wastegate hole? Simply opening up the wastegate hole and turbine inlet will not solve your boost creep problems. You need to open up the pathway to the wastegate hole to give your exhaust a smoother easier path through the wastegate hole.