GTRS late spool issue, hit 10psi at 4000RPM and 20psi at 5500RPM

[beejohn]

So I recently installed a gtrs eliminator kit and am having some issues with slow spool. My wastegate was adjusted so that it regulates boost at 5psi if I connect the charge pressure directly to the wastegate. (originally ATP sets the wastegate to 1bar)

Setup:
GTRS
Stock Exhaust Manifold no leaks (previously had 034 manifold and thought that might have been leaking, turns out it wasn't)
High-flow catalytic converter
MBC set to 20psi

is the wastegate setting I have too low leaking exhaust gasses and causing a slow spool? Or do you think the slow spool is because of boost leak, or other related issue?

so far i've tried pressure testing the system, found no leaks. switched to 710n. removed the n75 out of the equation.

[mike-2ptzero]

I still think your wg spring is set too low causing the wg to blow open when the exhaust pressure in front of it gets to 5psi.


Did you contact ATP to see what they set the WG at before it leaves their shop?

[AudiRacerS4]

I still think your wg spring is set too low causing the wg to blow open when the exhaust pressure in front of it gets to 5psi.


Did you contact ATP to see what they set the WG at before it leaves their shop?

x2 I know from the factory the wg is set to open at 15psi if yours is opening at 5psi thats your problem, also what size exhaust are you running? with my dump closed my spool is pretty slow, I dont hit full boost (27psi) until around 4500-4800rpm. with my dump open I'll hit full boost at 3800-4000rpm.

[firstars]

you also had this problem with the ATP manifold? I would think the mani might be choking you

[mike-2ptzero]

x2 I know from the factory the wg is set to open at 15psi if yours is opening at 5psi thats your problem, also what size exhaust are you running? with my dump closed my spool is pretty slow, I dont hit full boost (27psi) until around 4500-4800rpm. with my dump open I'll hit full boost at 3800-4000rpm.

What happen is that I think someone reset it to fully open at 15psi, problem is that now it is too weak to stay shut once the exhaust pressure builds up inside the exhaust housing. He needs to pull it back off and set it back to crack open at 15psi.

[AudiRacerS4]

What happen is that I think someone reset it to fully open at 15psi, problem is that now it is too weak to stay shut once the exhaust pressure builds up inside the exhaust housing. He needs to pull it back off and set it back to crack open at 15psi.

i think the stock exhaust manifold could be his problem too

[firstars]

i think the stock exhaust manifold could be his problem too

i have gt28 with stock manifold and doesnt fully spool untill after 4000

[mike-2ptzero]

i think the stock exhaust manifold could be his problem too

How is that? The stock manifold would spool up the turbo quicker since the runners are smaller and the velocity would be higher, it would limit amount of flow in the higher rpms not cause a later boost threshold.


I am sure in the last few years others have ran the elim on their stock manifold, I even think my last customer that is running the GTRS on his 2001 with REVO tune is running his on the stock manifold, well I dont remember selling him a ATP manifold but I guess I could call him up and ask to make sure. He did have a late boost issue on his K03 and GTRS kit once it was installed, but it was a bad N75 valve.

[beejohn]

I still think your wg spring is set too low causing the wg to blow open when the exhaust pressure in front of it gets to 5psi.


Did you contact ATP to see what they set the WG at before it leaves their shop?

ATP sets their WG at 1bar stock.

[beejohn]

i think the stock exhaust manifold could be his problem too

i had the 034 manifold on there earlier, same problem. In fact the 034 motorsport manifold had better top end, I could take it to 7k and still have gobs of power. With this stock manifold I can feel the midrange more, but I have to shift just before 6500rpm because there is just no more power.

[AudiRacerS4]

sounds like its a WG issue then

[AudiRacerS4]

How is that? The stock manifold would spool up the turbo quicker since the runners are smaller and the velocity would be higher, it would limit amount of flow in the higher rpms not cause a later boost threshold.


I am sure in the last few years others have ran the elim on their stock manifold, I even think my last customer that is running the GTRS on his 2001 with REVO tune is running his on the stock manifold, well I dont remember selling him a ATP manifold but I guess I could call him up and ask to make sure. He did have a late boost issue on his K03 and GTRS kit once it was installed, but it was a bad N75 valve.

idk when i had the stock manifold the car spooled later then with the 034 HF manifold

[Oricle]

My GTRS with a stock manifold is fully spooled before yours even hits 10 PSI. Have you tried a boost leak test?
I'd check for boost leaks and go from there.

[AudiRacerS4]

My GTRS with a stock manifold is fully spooled before yours even hits 10 PSI. Have you tried a boost leak test?
I'd check for boost leaks and go from there.

it also depends on his tune i dont hit full boost till around 4000 either

[gotaudi]

I still think your wg spring is set too low causing the wg to blow open when the exhaust pressure in front of it gets to 5psi.

the pressure in the exhaust manifold is greater than 5psi I believe. Back pressure in the manifold is pretty high, also for the wastegate flap to open due to exhaust gases the pressure in the exhaust housing would have to be greater than what the wastegate is set at. It think his problem is related to the wategate being set too low. ATP puts a 14psi wategate on the eliminators, to set a 14 psi wastegate to 5psi the wastegate arm would have to be unscrewed quite a bit. now if the wastegate is unscrewed so much that the wastegate flap is open slightly that would slow spool down quite a bit...