So I have heard that BOVs can be put onto TTs with some slight mods. I was wondering what you have to do to put a BOV onto my 2000 TT 180 Quattro? Is there any performance difference between haveing the BOV or the DV? I was originally looking at DVs but they are so much more expensive and I really don't have that much $ but really need the car to run. It is nearly impossible to drive now because the turbo builds no boost. The car studders and misfires so badly that you cant accelerate at all. Could this be something on top of the DV being blown out?

You really shouldn't run BOVs with our cars, our MAF and ECU rely on purged air being vented back into the intake system to properly manage the engine, fuel-air ratios, preventing misfires, etc. Don't run a BOV, they can seriously hamper the performance of the car. And the stock DV from Bosch is only like $40...(ecstuning.com), and an upgrade would be ~$110 for a Forge 007...

Read more about DVs vs BOVs here:

http://audiforums.com/forum/showthread.php?t=2780

Some quotes:

"The Audi turbo system is a closed loop system by which all unused boost that is spooled during off throttle and gear shifts must be re-routed within the system; it cannot be vented to the atmosphere due to the dependence on the MAF and ECU to properly read and interpret air flow dynamics within the intake tract. Therefore BOV's (Blow-Off Valves) are not used because they create a rich air/fuel condition (i.e. less air to fuel ratio) which will damage the catalytic converter, create soot on the exhaust pipes, and cause occasional misfiring (due to the purged air) which will result in ECU miscalculated timing adjustments and other errors. "


Also, I think you may want to read a FAQs about TTs and some basics on their mods here:

http://forums.fourtitude.com/zerothread?id=3443644



As for the no-boost problem you could have a serious vacuum leak somewhere, or a blown DV...or any number of problems in the charged air system. You could also need new spark plug, or coil packs. You could also have a bad MAF, those can be finiky I think you best be taking this to a specialist, its hard to diagnose via forum, but it sounds like either vacuum leak, MAF or Sparks/Coils to me....

hope this helps...

Jack

I agree you shouldn't run a BOV on our cars which require a certain amount of recirculation.  That said you can get a Forge Splitter Valve if you like that Swoosh sound.  It recirculates most of the air back into the system and vents about 10% or less to Athmosphere.  Or you have the choice to block the side vent completely and run it as a 100% DV.  I have had mine for about a year now and it works GREAT.  Besides it is easily adjustable with a twist of the top.  

Your problem does not sound like a Bad DV.  More like a major boost leak or an ignition problem.  Check your Turbo Outlet hose: http://www.ttstuff.com/mm5/merchant.mvc?Screen=PROD&Product_Code=FM225TH&Category_Code=T1PTTH

You can't see it and it is a bit hard to get to but it popped off the Turbo on my car once and It sputtered and ran like crap and I had the hardest time to track that issue down.  That hose does fail prematurely and the dealer will charge you 600+ to install a replacement which is lunacris. I did it in about 30 minutes and for less than a 100 bucks.   You may also check your coil packs and Spark Plugs, they are known to fail as well.    Aftermarket Diverter Valves will not gain you any performance.  Either your DV works or it doesn't.  If you are stock the updated Bosch 710N would work just fine.  If you want the Swoosh Sound I would recommend the Forge Splitter Valve

http://www.ttstuff.com/mm5/merchant.mvc?Screen=PROD&Product_Code=FMDVSPLTR-PL&Category_Code=T1PTDV