Overboost..EVEN when connected wastegate to J-pipe nipple.. help

[rowlex]

Ok. lets see if anyone can figure this one out. I've had 3 experienced tuners try to help, and an apexi authorized dealer. We are all stumped.

Vehicle background: 2G tsi awd, evoIII 16g, 2.5" o2 housing with a dumped wastegate, 3" DP-all the way back, walbro 255, 650cc injectors, aeromotive AFPR, HKS SSQV, stock SMIC, DSMLink for tuning. AVC-R for boost control. Nothing is ported, however the step is removed. Pressure tested with 1 leak at the TB shaft, experienced tuners said it's normal, and doesnt cause any problems on their cars.

With the AVC-R hooked up and set to hold boost at .6/.8 bar the wastegate will open at around 7 psi, stay open, but my boost will exceed 14 psi ----it goes however high it wants to and makes my car buck/jerk. With the AVC-R turned off - (which would be just like hooking a vacuum line to the WG to J-Pipe. It does the same thing. With a vacuum line straight to the Wastegate from the J-pipe, it does the same thing.

I put a bicycle pump style pressure to the wastegate vacuum hose, pumped it up. The wastegate began opening at 11psi and was fully open by 15 psi. Mind you it's bicycle pump style.

Any ideas?? I'm going to hook it back up to the stock solenoid and give it a try. Can anyone tell me which line on the stock solenoid goes to the wastegate?

TIA!

 

[oldman]

Do a search on boost creep.

 

[rowlex]

Thanks for the responce!

I did run a search but nothing seemed to answer my current problem creep was mentioned by my buddies but then got shot down when I told them before I had the SSQV/AVC-R installed I was running 12.7psi all day long.

I forgot to include this information:

On the stock BOV/BCS, same exact setup (minus the SSQV/AVC-R) I was able to hold 12.7 psi until red line. Pedal to the floor (for MONTHS even in 35* temps).

Still boost creep or do I have other problems?

 

[1FastFWD]

i had the same prob when i put my 3" turbo back exhaust on. i thought buying an o2 dump would solve my prob but it didnt end the boost creep...what you need to do is to port the wastegate opening on the turbo housing plus port your o2 housing/dump.

 

[oldman]

Thanks for the responce!

I did run a search but nothing seemed to answer my current problem creep was mentioned by my buddies but then got shot down when I told them before I had the SSQV/AVC-R installed I was running 12.7psi all day long.

I forgot to include this information:

On the stock BOV/BCS, same exact setup (minus the SSQV/AVC-R) I was able to hold 12.7 psi until red line. Pedal to the floor (for MONTHS even in 35* temps).

Still boost creep or do I have other problems?

The problem you described sounds very much like boost creep. Here are some possible causes that I can think of without knowing the full details of what was changed,

1. Your stock BOV or flange use to leak, after the SSQV install you have fixed the leak which incrased air flow and spool up time exposing your hidden creep problem.
2. I don't know the avcr setup but better design/material mbc can help with spool time.
3. The lower the boost setting the worst the creep, try turning up the avcr and see if situation improve.

 

[rowlex]

thanks for the help guys. I want to avoid pulling the turbo to port it, but if I have to I will.

Im going to try the stock BCS and see what happens. Gonna try easy stuff first... I'll try turning the boost up...I should be safe to hit 18PSI... Should I up my fuel per RPMS just to be safe or should the FPR handle it?