i have a 2000 A4 1.8t and i really want to find out what to do to get the blow off sound. Someone told me i needed a bypass valve? Does anyone have the correct info for me?

 

As a new member, please acquaint yourself with the stickied information at the top of the forum. I'll save you a small amount of effort, though, and give you this thread (which is stickied). https://www.audiforums.com/forum/b5-...%2A%2A-109459/

 

https://www.audiforums.com/forum/b5-...-valve-207129/

 

BOVs are ricey

 

Audis aren't made to run BOV's, you can DIY one up but to me that's silly. Why mess with the engine like that when you know it's not suppose to be there. Just asking for problems in the future I think.

 

I run a BOV. MAFless though

 

Read the thread I posted, I've ran the car with a blowoff for over half a year, yes car revs did drop and car hesitated at times but no damage was done, with the mod I done in the thread, car is running perfectly while having the blow off that a lot if people want.

Ps: when people say audis arnt meant to run with blow off, completely false, audis are simply not tuned to run with one from factory that is all, with a proper tune you can do what ever you wish. Read the thread and run it like I have, you will have a blow without affecting the operation of the car. Good luck.

 

Was this directed at me? I think I know a thing or two about BOV's. True, most people shouldn't use them though. If you really want to get specific, 01's are really the only b5's that are even slightly compatible with BOV's with a stock engine setup because of a wideband primary o2 sensor and a map sensor combined. AEB's and ATW's do not have both of those, and will run a tad rich between shifts, and a tad lean at idle with a single piston BOV. Dual piston valves would help the cause a bunch more, but it still isn't right.

The only reason I don't run a DV is because of my MAFless setup. I don't want to plumb an intake just to run a DV.

 

It wasn't directed at you redline but ChrisR712. Yeah I understand what your saying.

 

You are right that audis aren't meant to run a BOV, any car with a MAF isn't meant to run a BOV, not just audis. There's no way to tune it out as you mentioned because when the BOV opens you suddenly get a massive boost leak for a second or two, and of course a vacuum leak at idle and low throttle. That is unless you go mafless, which is a whole different ball game beyond the scope of this thread. As for your 'fix', all you did was turn your BOV into a DV so obviously it runs fine now. Why not just buy a DV from the beginning if you're going to recirculate it anyway?

This isn't directed at you, but for the millionth time, we do not have a MAP sensor. MAP stand for manifold absolute pressure, aka it has to be in the intake manifold after the TB, not in the boost piping. Our boost sensors do one thing only, which is report actual boost so that the ECU can compare it to requested boost, they're basically useless as a tuning measure.