DVs leaking from idle to 2k

savageN54

Lurker
Feb 2, 2018
14
2
0
Ride
2009 BMW 335xi
Hey guys, so I've noticed a leak from my DVs from idle to 2k, and under moderate acceleration, between shifts (AT).

Now don't flame me for this. But the car is VTT Stage 2+, inlets, outlets, fbo and upgraded lpfp, however I'm still running the stock DVs through a VRSF cp. Now, I know i could probably benefit from a BOV upgrade or forge DV, but for the meantime does anyone know why this could be happening?
 

cloud9blue

Sergeant
Oct 17, 2017
255
190
0
Ride
09 E92 335i
Your vacuum line for the DVs is leaking or kinked. DVs don't just leak only at certain RPM. if it is a torn diaphragm, it will leak at all time.

In your case, it is most likely because it isn't seeing the manifold pressure that it should see to keep the diaphragm closed.
 
Nov 5, 2016
615
625
0
Bay Area
By leaking you mean open? They should be open at idle, and under some cruise conditions. No vacuum is ever present in the charge pipe, literally ever. Only positive pressure, and no pressure. Having the prope. spring in either DV’s or a BOV so they are open under idle, and some cruising conditions, prevents on throttle surge at high load, low throttle angle. With that said, running stock DV’s with upgraded turbos, is a terrible idea
 

savageN54

Lurker
Feb 2, 2018
14
2
0
Ride
2009 BMW 335xi
Yes I mean open. I know open at idle, it is all just strange to me. The only reason it bothers me is because the response from a dig is crap. I plan on upgrading soon, but was looking for a small fix in the meantime. Thanks Tony, love your turbos
 

cloud9blue

Sergeant
Oct 17, 2017
255
190
0
Ride
09 E92 335i
You are just wasting money replacing those perfectly fine DVs. Those "upgraded" aftermarket DVs actually perform worse than the stock ones from my experience with them.

Crappy low end response is probably just a worn out wastegate on your old ass turbos.
 

savageN54

Lurker
Feb 2, 2018
14
2
0
Ride
2009 BMW 335xi
You are just wasting money replacing those perfectly fine DVs. Those "upgraded" aftermarket DVs actually perform worse than the stock ones from my experience with them.

Crappy low end response is probably just a worn out wastegate on your old ass turbos.
My turbos are brand new VTT stage 2+ lol. I promise that's not it
 

savageN54

Lurker
Feb 2, 2018
14
2
0
Ride
2009 BMW 335xi
tuning then? i just don't understand how and why you so quickly blame it on DVs if you are changing whole bunch of other stuff.
I've had this setup for two months now. Just now really noticing it. I am "so quickly blaming" because that's what is leaking. Im not dumb, I know how to test and rule other options out. I posted "DVs leaking* because that is what's leaking.
 
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