C Murda

iTrader: (24)

mine does the same thing at the same rpms...cept i dont have boost yet and its through kooks LTs ORY and LM catback...i kinda like it maybe its cause i got tractor envy

TS6

iTrader: (41)

No, its not coming from the wastegate. Its coming from the inlet of the turbo. You close the throttle, the turbo doesn't just stop spinning at high rpms. But the air has nowhere to go so it comes back through the compressor, making the noise.

smoke20

iTrader: (2)

when you put it that way it makes much more sense, i better get a BOV that cant be good on the ole compressor.

Turbo Tech

iTrader: (2)

The noise you are hearing may be caused by the wastegate being open under vacuum. Check to be sure the boost side of the wastegate is routed from the compressor housing. If it's hooked to vacuum the gate will open under decel or high vacuum. The bov should release all at once. If you hear a flutter from the bov then you may need a larger one. If the discharge air is comming from the turbo inlet the bov is to small or not working. Depending what bov you have there are many different springs available to speed up the valve. George

smoke20

iTrader: (2)

i dont have a BOV installed on the STS system, i assumed the noise was from the wastegate , i know i need to install a BOV so that will be my winter project. what size BOV would you recommend im currently running 9psi with the plans to go up to 12-15 psi.

SonofaBish

iTrader: (5)

50mm Tial is a great one...

there is a thread around here somewhere with a poll about BOVs

Wanttogofaster

Thanks everyone for giving me some good information on this subject. I have a Tail 50mm blowoff valve, Im only boosting to 5.5lb so maybe the spring in the blowoff valve is to large and is causing this. I dont no what size spring it comes with, but if thats the problem can you cut the spring to make it shorter.