The ST165 and ST185 did not come equipped with an air bypass valve for turbo protection.  Due to the lack of spacing and customer support kits were never created for these vehicles.  Here is the information about the universal valves available so that you may create your own system.  If you are buying a Blow Off Valve, regardless of brand, be sure to get the universal kit unless otherwise specified.  For more information about what a Blow Off Valve is, visit the BOV FAQ

A bypass valve will release turbo pressure between shifts.  The term "bypass" relates to the idea that the turbo air is then rerouted back into the intake.  These valves are designed to be fully open in any amount of vacuum, so they can only be routed back into the intake, otherwise stalling would occur.  It can be argued this is the "proper" way to release turbo pressure so that no air is ever lost from the intake system.  This is also the same setup that the ST205 GT-four and Supra Turbos use.

Standard bypass valve, great starter to preserve turbo life.  Has a tendency to hang open during part throttle.  Known as a "hoot".  They range from $33-$45 retail depending on which version you would like to use.

Sound: Owl Hooting sound, Listen (wav)

 

Style	BOSCH #	AUDI #	PORSCHE #
Standard	0280142103
Tough (Thicker diaphragm, Long Life)	0280142102	035 145 710	944 Twin turbo
Metal (Brass Piston, Fast Response)	0280142108	034 145 710C	993.110.337.50
*UPDATE:  The standard version is available from ABJ,  $20.50 + shipping.  Call 888-885-3500.
*UPDATE:  The metal version is available from Powertech in NJ,  $35 + 8 shipping.  Call 973-586-3210.  Ask for Mike or Andreas.

(UK)

This bypass valve version of the popular Bailey dump valve is designed to be a high quality upgrade for the Bosch BOV.  This is a full metal piece which will not wear out over time.  It is also capable of holding very high boost pressure reliably.

Sound: ?

PN# DV 30 Dump Valve (Recirculate) £99.88

This is the "racing" version of the popular Turbo XS Blow Off Valve series.  The company claims extremely high flow rates.  It is designed to be routed back into the intake system for the best response during racing situations.

 

Description	Part #	Price
Type H Racing Bypass	#RBV H34	$179
Type H 90 degree flange		$ 39
Type H tube adapter flange		$ 39

*You can receive $30 off XS valves at carparts.com by clicking HERE.  The discount will automatically be applied!