klein

i dont have the same turbo, but the same BOV system.

mine is an td04-16t
from a volvo 850 R-->5 cil with 250 bhp..

isnt it possible that it can handle a little more psi??

Foowee

I have one of these 12b turbos sitting on my shelf. I would like to install it on a bike in the future. I'd like to see if I can mod the bov like this:

http://www.thedodgegarage.com/turbo_bov_mod.html

I'm not a big fan of crushing them. I think blocking off the boost source from the compressor housing to the bov shouldn't be too challenging. Just have to see if venting the bottom side of the diaphragm to atmosphere is feasable.

D16y8 I see you have an adapter plate on yours. How did you seal the turbine against the plate with that recess in the flange?

sixsick6

You're so uninformed. Blow off valves and bypass valves are always open during vacuum. The only time that either closes is when you reach + boost pressure 0<psi. The reason you hear the audible sounds is because your throttle plates close (shifting) and you go under vacuum long enough for the valve to open and boost pressure to escape.

Blow off valves while working the same as bypass valves, also have the ability to be adjusted. This allows for less opening/venting at idle (hard setting) which increases spring tension and the valve needs more vacuum to open. On the soft setting, you'll notice that you can blow off at idle. This is nothing but the lowest amount that the spring needs to open the diaphragm and allow minimal boost pressure to escape with maximum noise.

Notice that if you have yours adjusted at it's "hard" setting that it won't blow off at idle and your boost will feel more consistant, this is because you're not losing boost pressure from a weak setting.

As far as the DSM bypass, it needs 17 inHg to even START opening and isn't fully open until 25 inHg.

If you were getting flutter, it's because your engine wasn't creating enough vacuum to open the valve effectively in the first place, not because it was leaking under boost. It might have opened some, but not enough, which is why you heard flutter.

Foowee

Fluttering can also be caused by a structurally weak vacume line, colapsing under vacume and not allowing the bov to function properly.

sixsick6

Beside the point that it doesn't even start opening untill 17 inHg and isn't fully open untill 25 inHg:













As for an understanding of how a bypass or blow off valve works:


And here is a movie for you as well:
http://jholland.phpwebhosting.com/si...urbo%20007.MOV