BOV Setup for your N54

RuskiRacer

Sergeant
Jul 17, 2019
467
170
0
Ride
2009 e93 335i
If you don't like how the tial sounds with silicone inlets maybe get a gfb or a turbosmart? Its gonna make that noise with the inlets your just gonna have to live with it or get a different brand bov. 7psi spring is fine you can see it closes under boost and releases pressure very quickly.
 

IQraceworks

Specialist
Jul 7, 2020
77
25
0
Missouri
Ride
07' BMW 335i
Couple things:

1: BOV spring is fine. I wouldn't change it.
2: Log indicates -to me- tune is aggressive, and will use throttle control as a means of trimming a bit more than we typically see thus you're making the BOV do work. If you put a stiffer spring in you'll make the activation rate go down but you're aggressive. I assume this was done to make the car more responsive and I'm sure it works. Not shy with the WGDC.

Bottom line is I'd keep the BOV spring and ditch the tune. I'm sure it's a powerful tune and feels good but IMO it's aggressive.
The only thing that doesn't make sense to me is that I've tried several different tunes (this is the V5 E40 Stage 2+ MH OTS Tun)....and even with much milder tunes, I still get that hooting sound....and I can still get the BOV to flutter. Whatever it is....it sounds like it's reall common for some reason, and nobody has really found a "Fix" except when that change a whole bunch of things at once (new turbos, reloated inlets, aftermarket tune, etc, etc), and then the sound just magically goes away.....not knowing what really did it.
 

jareddlc

New Member
May 1, 2021
2
0
0
Sorry if this was already answered, but which is the correct spring for the turbosmart bov? I may consider buying it.