Hi,
do anyone has any clue why my stock turbo lag?
No boost leak.

My current engine spec's :
85.5mm Piston
GSC S2 cams
Ralliart I/C pipings
600mm x 300mm x 75mm IC
Stock TB & Int Manifold
Banana Manifold with Turbosmart 21psi spring w/g
Profec B II Boost Controller

I recently has adjusted the boost controller and will it effect the map which also caused the lag?

My turbo start boosting at 3700rpm

 

remove the turbo elbow and check the the wastegate flap. some double flap wastegates have known to wear and not seat correctly causing the lag you describe.

is it an external W/G your using?

 

Hi Evonut,
yes, im using external wg...Turbosmart 21psi spring.

 

Btw, will a leaking exhaust or exh manifold cause lag?

 

does your wastegate feed pipe off the manifold come from both scrolls?
have you had your car properly tuned yet?

 

Hi RSMike,
on the wg feed pipe im not very sure and ive tune my car abt a month ago but the boost still start on abt 3400rpm and after i adjusted the boost controller the start boost comes even later around 3700rpm...

 

go and have a look at your car and see if the pipe comes off both scrolls or just 1 scroll

 

Hi RsMike, i think is 1 scroll..
Can view some pics on "Pls comment on my set-up" thread...
Thanks

 

thats looks like your wastegate is coming off both scrolls, and i bet it doesn't have a divider in it.
This will cause 500-700rpm extra lag over a stock wastegate setup.

 

No wonder!!!

Thanks RSMike...

 

i hope you didn't weld the internal wastegate shut.
i would take off the external wastegate, weld those pipes closed and run the internal wastegate.
If you do this, MAKE SURE YOU GET IT RETUNED.
the new zones will need to be remapped.
DO NOT BOOST IN THOSE NEW ZONES

 

Mike! You are

And yes, i did weld the internal w/g...