over boosting

'06 LGT

Finally got the motor back together with a bunch of new parts, having a few issues.

-SixStarSpeed SS-30XR (11psi spring)
-Cobb CAI
-Cobb BPV
-Perrin Inlet
-Grimmspeed TMIC/EBCS
-TGV Top Feed deletes
-ID 1000
-more

I'm in the middle of tuning with Dave @Cryo, with the break in tune complete and some miles on the motor, we moved on towards the power tune. First real pull and I hit 20psi. Dave wants 0psi.

I pull the waste gate actuator arm and move the flapper to make sure there is no obstruction. It moves freely.

Used a bike pump to test the actuator and it opens easily at around 12psi, Hook it back up to the waste gate valve and it takes 20+psi to open. Hmm.

There was a lot of preload on the actuator spring and it was hard getting it off the flapper valve, I thought maybe with a big preload the wastage valve would take more pressure to open.

I adjusted the actuator so it would open at around 12 psi.

Instead of over boosting to 20+ psi now I hit 15 psi. Still over boosting.

Check my vac lines by blowing through ports 2 and 3, no restrictions. Can't blow anything through port 1. Seems normal.

Re-route the vac lines on top of intake runners incase they were getting pinched under boost. No change.

Replace vac lines. No change.

Looking for a fresh set of eyes to help me out.

Size of restrictor pill in wastegate hose?

No pill, 3 port EBCS.

I bypassed the Grimmspeed EBCS and routed the pressure line off the turbo directly to the wastegate actuator, I also adjusted the arm so there is minimal preload on the spring.

2nd gear pull I hit 11.84psi. Cool.
3rd gear partial pull I hit 20+psi. Not cool.

Ugh.

Rig your wastegate wide open with some safety wire or something? Then you can at least rule out the wastegate being undersized.

Originally Posted by bermo

No pill, 3 port EBCS.

I bypassed the Grimmspeed EBCS and routed the pressure line off the turbo directly to the wastegate actuator, I also adjusted the arm so there is minimal preload on the spring.

2nd gear pull I hit 11.84psi. Cool.
3rd gear partial pull I hit 20+psi. Not cool.

Ugh.

Straight from turbo housing to WG should be at WG pressure. Right?

Originally Posted by Captainlvsac

Rig your wastegate wide open with some safety wire or something? Then you can at least rule out the wastegate being undersized.

I did hit wastegate pressure in 2nd gear? Maybe the actuator closed up some? I'll try that when the weather gets warmer.

Originally Posted by wbrawley

Straight from turbo housing to WG should be at WG pressure. Right?

Correct.

The actuator has an 11psi spring, so the 11.84psi I hit in 2nd gear seems fine.

The 20+psi in 3rd gear with the same set up is worrisome. It was 25º outside? Maybe boost creep?

Bad actuator?

Originally Posted by relative4

Bad actuator?

Not sure?

Turbo/actuator are new. Less than 1K miles.

I am starting to think the actuator is fine, I did hit wastegate pressure in 2nd gear when bypassing EBCS. Its the more flow in 3rd gear thing that I am worried about.

Anybody dealt with boost creep?

Maybe the divorced wastegate, catless, 3" downpipe is too free flowing? Choke the thing up a little with a bellmouth catted downpipe?

I know many people with catless DP have dealt with boost creep.

That turbo isn't very common and I'd hate to spring for a catted DP and end up in the same place.

Dave would be the ideal person to help you with this. What has he said?

Originally Posted by gkinslow

I know many people with catless DP have dealt with boost creep.

That turbo isn't very common and I'd hate to spring for a catted DP and end up in the same place.

Dave would be the ideal person to help you with this. What has he said?

Too bad nobody makes a restriction piece to test that. Like a 3" to 1" cone to put at the end of the DP. Hey! Better yet, make a plate with a small hole in it where the DP to mid-pipe gasket goes for back pressure? Just an idea.

I know its not the same turbo but I had boost creep issues with my old VF52 paired with a GS CAI, CNT catted DP and catback exhaust. With OEM airbox I was fine.

My solution was to port/smooth the wastegate edges in the hotside housing.

Originally Posted by Captainlvsac

Rig your wastegate wide open with some safety wire or something? Then you can at least rule out the wastegate being undersized.

I like that idea.

Originally Posted by gkinslow

I know many people with catless DP have dealt with boost creep.

That turbo isn't very common and I'd hate to spring for a catted DP and end up in the same place.

Dave would be the ideal person to help you with this. What has he said?

Dave is thinking its the wastegate, Im' gonna use Captainlvsac idea and run it with the wastegate wide open and see if it builds boost.

Really don't want to pull the turbo in 25º weather.

Wired the wastegate fully open (which is farther than actuator travels) and was able to boost 10psi before I let off. It was super laggy, then the boost came on super quick.

Plan forward is to have a shop port the wastegate cause I've never done that and it I'd bet it would get too much portin'.

At the same time put on a bellmouth catted downpipe, been wanting to do that anyway.

My goal is to increase flow through the wastegate and give the exhaust a little back pressure.

Might be cheaper and more effective to go EWG?

I would assume any porting is kinda trial and error.

Not sure I want to go in that direction, trying to keep this car somewhat civil. >_<

EWG sound horrid to me.