the way the 1.8t system works is such; when shifting or otherwise causing DV operation the charged air the air is let out of the charge pipe and recirculated back into the intake path, the computer knows that this is going to happen so it adds appropriate fuel. when you install a BOV the air that was getting recirculated is now just getting vented to the atmosphere, the computer is still expecting the extra air and adds fuel, but the air is not there, well its there there is just less of it. this causes the engine to run rich for a moment while the air catches up after the bov is closed. the theory is that it runs rich enough to cause the cataylitic(sp?) converter to get clogged, and possibly the spark plugs to foul, i have even hear that there is enough of a rich condition to WASH THE CYLINDERS! lol.

now personally i understand the way this works, but i feel the it is running so insignifigantly rich that it will cause no problems at all, its just rumor, i have yet to hear a CONFIRMED account where a bov has actually caused any damage. one quick point, i run a bov, and a test pipe, i nor anyone else has ever seen any dark smoke from my exhaust when shifting or any other time. very soon i will be hooking up my wideband o2 sensor to confirm what i believe to be true.

for the record my brother has run his bov on his passat for around 15,000 miles, with a cat, chipped etc, NO problems, the secondary o2 sensor read fine, and it passed emissions with stars.

All true, but its the Gay high pitched anoying sound that attracts 16 yo's, its also a good reminder that a 150hp monster is coming.

Just got the Forge 007 DV. Sounds the same as my stock DV.

My Forge DV sounds nothing like that in the clip you posted. It sounds stock. That car in the clip sounds like it has exhaust and maybe a turbo upgrade. Not sure if an intake would make the DV sound that much louder.

So does the 1.8T use an afm, or a map sensor? If its a map sensor, it shouldn't really make a difference, should it?? On the Mr2 the AFM would cause the same over-fueling problems you are talking about, as you would be dumping pre-metred air, but there were no such problems with a map sensor, because it only took into account the air that was after the dump, rather than before, thus no over fueling?
(Sorry if it makes no sense, but I'm no mechanic!!)

well iam going to be adding an intake soon to see if its true and iam also going to change the Turbo inlet Hose to the Samco one, and the clucth fan to an electric one, but from what ive read on VWVortex an intake will make a BOV like sound.

It's the intake that does it, run the car with no airbox, same effect, you can hear the DV working then.

The Audi system seems to fuel solely on the MAF hence the nickname "closed loop" turbo system, metered air enters and the ecu will fuel according to that meter reading. You dump into the atmosphere and the ecu will still try to fuel for that pressurised air, you'll still be getting some air in obviously so the effects aren't to major but you're definitely over fueling while the boost builds back up.

I've spent more time working with systems where the boost and therefore the air level is sensed via MAP sensor. The MAP method of air/boost sensing will allow the use of BOV, some people shout about the benefits of them ie prolonging turbo life etc, but that only really applies to massive turbos where the blades are likely to be opened up by high speed stalling, you can stall a smaller turbo fine and hold some boost back rather than dumping it all and getting a faster spool up time on the next gear shift.

Cheers Paul. I always thought that MAPS were pretty much OK for bov's, and AFM's were the ones with the trouble. Thanks for the info anyway! I'm not interested that much in bov's, but I like to know a little bit about each thing, so thats for the info!

Greenday, definitely let us know what you find. I still don't think it will cause an end to the hatred of BOV's though. PSSSSSHHHH

lol i will definently let you guys know what i find, the bov i use doesn't sound ricey, no high pitched whistle here. my brother sold his passat and gave me the bov, who am i to say no? lol especially with a leaky stock dv. sorry i didn't get the results today, it was really hot today at work and i don't do well with hot weather lol, damn im lazy. ill try to get it done tomorrow.