Hi,
im currently running on a GT3076R turbo with Turbosmart 38mm WG.
Boosting 1.6 bar (Low) & 1.8 bar (High) and what is the ideal spring rate should i pick? Can a 1 bar spring rate do the job?

Current 38mm WG is running dual spring.

My problem is whenever high speed + rev, i have to keep on WOT (Boosting all the way) because whenever i let off the throttle a little my engine jerk vigorously and ive to immediately WOT again...What is happening?

Is it due to :
1) Tuning?
2) WG spring rate (tension to high)
3) BOV (Ive just recently installed a Turbosmart race port bov) which encounter mechanical failure just after a week installed and now after got replacement, we noticed its has a mild vacumn leak when doing boost leak test.

Thanks and hope someone can share some tips.

 

sounds like your blow off valve isnt opening. as far as wastegate springs go, a 1 bar should work fine, but i always go as stiff as possible to get it close to the lowest boost i will run.

 

sounds like tune.. no lift to shift is probably turned on.

as for the wastegate spring.. 1 bar should be ok since youre targeting such low boost pressures. maybe 1.2 bar if you can.

the turbosmart bov.. make sure you got the proper spring in that also.

 

posted same time as you - lol

 

Thanks Guys...Truly appreciate it...

But not only the engine jerk vigorously my boost meter flapping vigorously too until i WOT again...

If its a tune issue what should i tell my tuner?

 

can you hear the bov releasing the air? what spring is in it?

 

Im not sure...I believed it come with the standard bov spring...
Honestly, the main reason i need to lift off the throttle is bcos whenever i WOT with full boosting, i heard the WG & BOV is kept open.
That's why i need to lift off a little and throttle again...

 

so at wot you hear air rushing out of the bov?

 

I think so but WG im 100% assured.

 

Sounds like compressor surged ...

 

how to over come the surge Boonkae?

Have sent for a fine tune today, and we have confirmed the WG is doing great but the Bov is kept opening when boost reach 1.6 bar.

My tuner said whenever the bov open, the AFR read much richer???