Originally posted by CTX-SLPR
Howdy,
I just wanted to add something to this, maybe add abit more understanding for those always want to know why.
Adding a Blow Off Valve is a bad idea on TR's because the MAF is located in front of the turbo, this means once the air passes through the MAF it has been accounted for by the computer, if you blow off to atmosphere, your car will run rich as long as the valve is open due to the computer thinking more air is going through the system than really is making it into the engine.
Adding a Compressor Bypass Valve on the other hand is a reasonable idea, not a good one because of reasons already pointed out mainly related to need. The compressor bypass valve routes the air from the turbo's outlet back to its inlet keeping the air inside the system which keeps the computer happy, it also keeps your turbo spooled up kind of like blowing on a fan after you pull the power keeps it from slowing down as fast.
If you relocate the MAF to after the turbo it then becomes feasable to run a BOV and probably a good idea to run one of the two since a MAF simply reads air movement through it no mater the directions, so when you slam the throttle blades shut under booste you can get reversion and unstable MAF readings if the pressure is not vented off.
Happy to Help,