Tial designed this blow off valve to work correctly with vehicles that rely on recirculating the blow off valve into the intake system before the turbo to maintain factory-quality drivability.
Many factory turbo setups feed blow off valve discharge air back into the intake after the air flow meter. The factory air flow meter is expecting this air to be there, and sends a signal to the ecu to provide enough fuel from the injectors to provide for it. If you upgrade to a non-recirculating blow off valve that dumps to the atmosphere, the discharge air is no longer feeding back into the intake after the air flow meter. This creates a problem because the ecu, and air flow meter do not know that this air is no longer making it back into the system, but its still assuming it is, so it continues to provide more fuel for the air its not actually getting. This creates a "rich" condition where the air fuel ratio gets unbalanced by having too much fuel and not enough air during "off throttle" conditions like shifting or decelerating. This can cause the car to stall, sputter, and decrease drivabilty in general. Even worse, it can cause spark plugs to become fouled, ruining them .
Tial designed this BOV to come with 3 different outlet adatpers: 1" , 1.14" and 1.5". This allows this blow off valve to be an easy install for vehicles that came from the factory with corresponding size recirculating hose. The 1.0 inch is for a Bosch style valve (Subaru). There is also a 1.14 inch adapter made specifically for R35 Nissan GTR applications, and a 1.5 inch adapter for Mitsubishi applications. Select the correct adapter. SPECIFICATIONS
Spring Pressure Selection Recommendation:
- For use on turbo-charged and super-charged applications (Paxton, Vortec, etc.). The body and all internal components are CNC-machined from 6061 aluminum alloy. It features a large 1.98 in (50.5mm) valve.
- The V-Band design aluminum mounting clamp gives a very clean and unique appearance. The clamp uses Stainless Steel hardware for a long lasting, corrosion-free appearance.
- The valve seal utilizes a Viton O-ring that is clamped in place to prevent the possibility of sticking to the seat and pulling out. The valve stem and guide are Teflon-lubricated, hard anodize-coated for wear resistance.
- The Blow Off Valve also comes with our own machined aluminum banjo-type air fitting and bolt, with over sized 10mm hose barb for quick actuator response. The actuator has a high temp silicone Nomex-reinforced diaphragm for long life.
- An aluminum or mild steel weld base mounting flange is furnished with each unit. Stainless Steel is available at an additional cost. The use of 6061 aluminum allows the housing to be anodized with a selection of colors.
- Color anodized aluminum options (Silver, Red, Blue, Purple, Black).
- A single QR BOV can support up to 600hp
- Multiple return port options for easy OE fit
- -2psi spring for supercharged applications
Use the following information as a guide to select the appropriate spring pressure on the drop down for your application:
-16 in. to -19 in. of engine vacuum select an 10 PSI spring
-12 in. to -15 in. of engine vacuum select an 8 PSI spring.
-18 in. to -20 in. of engine vacuum select an 11 PSI spring.