Hey I put 2 TUNED Bailey Blow off valves on my B5S. I know a lot of you disprove the idea of putting bov's on S4's but I'd like to think if tuned properly, it'd be ok.
http://forums.audiworld.com/showthread.php?p=12673257

Anyway, on to my question. Upon installation, I made sure that the valve would stay closed during idle. They did; check. So I'm not idling rough or anything. No engine codes on running rich, so thats good too; check. NOW the last checkpoint, holding air until throttle release.... no check...

I had someone rev the car as I held my hand over the BoV. Idles fine, but when my buddy started revving it, the valves were releasing air already! But at least when he let off, they released the rest of the air like they are supposta.

So any ideas what could be the problem? [don't flame please =D ]

 

check to make sure the spring rates are correct for the psi the car makes.

I plan on switching to BOV's once I begin tracking my car more; as a daily I've heard they aren't as great, but at WOT a DV can't work as efficiently as a proper atmospheric valve.

 

ya i agree, to me it seems like you'd need a stronger spring

 

over a long period of time i do think that you will have issues. not sure how serious but they will effect fuel trims and such. whatever air the MAF relates the ecu thinks that it is ending up in the combustion chamber.. there will be issues.... good luck

 

^ true, it would be nice to have a tune for it. however, it also depends on how much the manifold pressure sensor corrects for that loss (i really don't know if it would much though).

 

ok, so there isnt a way for me to screw in the back side or anything like that? i have to get a new spring?

 

most likely not, but double check that you have all the hoses connected correctly before you shop for new springs, sometimes it's not that complicated... a common misfortune of owning a B5