COBB XLE Bypass Valve Improvements

The bypass valve is a straightforward component that can be found in most turbocharged engines.  Its purpose is to relieve boost pressure in the intake tract when the throttle blade closes.  This is done to decrease wear on turbo and engine parts.  While this is a fairly simple task, leaks or inconsistencies in the operation of the bypass valve can occur.  These occurrences will diminish a car’s performance.  With that in mind, the COBB Bypass Valve (BPV) has a new revision with some key feature updates that ensure leak free operation through the highest of boost pressures.

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Even the smallest inconsistency in the piston or mating surface can result in a leak.   This is why the COBB BPV is fully constructed with billet aluminum.  This process yields stronger parts that are made with a higher degree of precision than traditional cast methods.  The XLE BPV also features o-ring sealing.  Not only is this the best safeguard against leaks, but in the unlikely event of an o-ring failure, o-ring sealing allows the unit to be easily rebuilt.  The new revision also features a larger diameter piston which evacuates pressurized air more quickly making the unit more responsive.  Vacuum line routing has also been improved.  The new design offers the installer to choose between three different ports to assign the vacuum source.  This makes for a cleaner install requiring less vacuum hose.

The COBB BPV is still hard anodized and teflon coated which provides low sliding friction, reduces surface wear, and minimizes maintenance requirements.  The spring pre-load retains its adjust-ability.  The 50/50 block off plate which allowed for air to be vented has been removed.  This prevents rich fueling conditions for cars that are not properly equipped to vent air to the atmosphere.  Vehicles properly equipped with a speed density tuning strategy can simply remove the re-circulation hose making a fully vent to atmosphere blow-off valve.

The new COBB XLE BPV is new and improved with better sealing, easier installation, and faster response.  It is available for the 2008-2014 WRX, 2009-2013 FXT, AND 2005-2009 LGT, the 07+ Mazdaspeed3 and 06-07 Mazdaspeed6, the 08+ Mitsubishi Evo X and 08+ Lancer Ralliart, the 08+ Nissan GT-R, and the 02-07 WRX, 06+ STI, and the 06-08 FXT.



10 responses to “COBB XLE Bypass Valve Improvements”

  1. Are there any known problems with the discontinued XLE BPV, or is this a very much optional upgrade?

  2. I just installed the XLE Bypass Valve and after about 20 min of driving my 13 wrx . The car started to run rough and my check engine light came on. I checked and made sure there were no leaks from installing the vavle. Now is there any reason why it ran rough and the light came on?

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