Cannot control boost on holset?

[enjoyrth]

I have installed my HX35 and everything works very well, but I cannot control the boost on it at all. I first thought it might be because my wastegate actuator was not opening the wastegate enough, but I took these pictures comparing how far it opens with the stock flange with the 3"vband outlet and how far it opens with my bellmouthish downpipe. It seems to open further with my downpipe, but I still cannot stop the turbo from boosting. I took an air compressor and stuck it on the vacuum line that runs from the manifold to my wastegate actuator to verify that the actuator was still in good working order, and it was. Does anyone have any idea why my boost isnt stopping at the stock level with the stock actuator? Or better yet, why it isnt stopping at all? Is there something right in front of my face that I am missing? Its a simple mechanism and I cannot understand what is failing....

edit: I have had the vacuum line coming from the compressor housing and coming from the intake manifold, if that matters.

EDIT II: Pretty sure its a leaky diaphram, I will let you know when I get a new one.

closed:

stock:


my bellmouthish downpipe:

[2+2turbo]

isnt the stock WG actuator on the holsets set for like 20psi?

have you tried running the car with the wastegate open? (no actuator)

[StreetFighter]

That little flapper valve should open 45 degrees or more. Did you open up the wastegate port while everything was apart? That port size is made for high boost. You need to make the wastegate port larger, or go to an external gate.

[Dave88SS]

2+2turbo wrote: isnt the stock WG actuator on the holsets set for like 20psi?

additionally, 'stock' boost is higher when you have a larger than stock exhaust.

[Stinky]

Regardless of how i set my hy35 it creeps to 15psi by max rpm. The holset internal gate is likely too small.

[zmech]

[roastin300]

Welcome to the world of holset! They are so efficient and love to spool even with their size that you WILL NOT get stock 6-7psi of boost. Thats why you cant really run a holset on stock injectors and ecu because it wants to push alot of boost. Even with my HX35 with the wastegate WIDE OPEN, it will spool 10psi+ in 2nd gear and up! Im porting the wastegate hole ridiculously huge and welding on a new flapper thats much bigger to try and get the boost down. My buddy has a HY35 on his car and did this and was able to get the boost down to 10psi solid, before it would push12-14psi and creep up to like 16-17psi minimum. This seems to be the solution to get the boost down a little bit, but if you want stock boost, an external gate is needed. Oh and me and my buddy run other stock wastegates from gasoline cars off of other T3's so no im not running the stock holset wastegate....

[enjoyrth]

I swapped in a t3 wastegate actuator. It now holds pretty solid at ~18psi. I am happy with that, but now its time to crank it up quite a bit! :twisted: (I am running uber rich on a super conservative map right now, so I know it can handle more boost) My local speed shop told me that this would happen with the small wastegate flapper, but it holds very well at 18psi now, as my MAP sensor datalogging shows.