GT2 blow off valve
08-14-2002, 11:34 PM
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GT2 blow off valve
I am not sure if this is the correct description of the part, but has anyone replaced their stock blow off valve with either a GT2 vacum operated valve or any other aftermarket valve. If so, did you notice a decrease in turbo lag or any other benefits?
Bob M.
Bob M.
08-15-2002, 12:40 AM
#2
Three Wheelin'
Bob, The Diverter Valves (DV's) on the 996tt Porsches function as pop off valves (blow off valves). The main difference is that DV's divert the excess gases back into the intake, where as the pop off valves vent into the atmoshpere.
Most turbo owners that have made changes to DV's have been due to a defective design (torn or leaking diaphram). If you have no problems with boost or an audible moaning/honking (like a geese)sound when on boost there is really no gain in perceptible performance. Maybe a noticeable crispness off and on throttle between shifts at most.
Most turbo owners that have made changes to DV's have been due to a defective design (torn or leaking diaphram). If you have no problems with boost or an audible moaning/honking (like a geese)sound when on boost there is really no gain in perceptible performance. Maybe a noticeable crispness off and on throttle between shifts at most.
08-15-2002, 11:57 AM
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Oak,
Thanks for the reply. The reason for this question, was the thinking that a vacum operated valve (like on the GT2?)would be more efficient in venting the excess pressure created when the throttle is released, which would then keep the turbos spinning more freely, since there would be less pressure for them to spin against. As I understand it, the stock TT diverter valve works in a more passive way, meaning that the diaphram releases pressure after it builds to a predetermined point of resistance and once it drops down past that point it closes up again, possibly trapping more pressure than a vacum operated valve would do. Anyway, it was just a thought and it sounds like from what you are saying that the gains would be minimal.
Thanks for the reply. The reason for this question, was the thinking that a vacum operated valve (like on the GT2?)would be more efficient in venting the excess pressure created when the throttle is released, which would then keep the turbos spinning more freely, since there would be less pressure for them to spin against. As I understand it, the stock TT diverter valve works in a more passive way, meaning that the diaphram releases pressure after it builds to a predetermined point of resistance and once it drops down past that point it closes up again, possibly trapping more pressure than a vacum operated valve would do. Anyway, it was just a thought and it sounds like from what you are saying that the gains would be minimal.
