turbo compressor surge? pure 600's on the way out? (engine bay video attached)

rhzo10

New Member
Oct 30, 2021
1
0
0
My 335is is making weird whooshing noises, sounds like turbos are rapidly gasping for air. This started a few days after fixing a boost leak (missing o ring in charge pipe), checked coupler tightness, reseated charge pipe, opened up TIAL BOV assembly (spring was good, gaskets in place), all vacuum lines in good condition.

This noise occurs at around 20%-40% throttle, no codes, and the car pulls strong reaching 22psi. No codes, no boost-leak symptoms. Running Pure 600's which are 6k miles old.

Link to video:

Log Attached: https://datazap.me/u/armandolabrada/...ata=3-22-29-30

Any advice would be greatly appreciated!
 

vonhassen

Lurker
Dec 4, 2019
10
6
0
Ride
2009 E60 535xi
I wouldn't be concerned about this, every N54 with upgraded twins I have ever driven or rode in does this. It seems to happen when you are just above the minimal throttle needed to hold your current speed.

My friend swapped his BOV setup from a HKS to a Tial while we were trying to figure this out originally after installing PS2 hi-flows, but it happens with either brand (though you can reduce it with a heavier spring in the Tial).

My 2 best guesses are:
  • The drive by wire mapping of the throttle isnt actually just holding the throttle at the exact same spot, and this noise come from the feedback loop of your throttle map trying to maintain a certain requested load or whatever.
  • If the throttle position change is negligible when this happens, then it could be caused by the oscillation frequency of the pressure waves in the intake manifold that occurs when maintaining a specific throttle input and/or requested load within a specific RPM range (and in-turn, within an specific area of the turbos' compressor map)

Hit up your tuner if you want to be sure, but hopefully someone can chime in with a definitative answer on this... even if only to tell me I'm dumb & wrong lol
 

rev210

Corporal
Feb 24, 2019
203
96
50
Ride
335i - 08 Coupe .
You can tune it out, ask your tuner.
Nothing to do with BOV , its compressor surge . Common on twin highflow turbos ,inc RB26 gtrs . Light throttle surge isnt a big deal , full throttle is. But, fix it as its not ideal.for the turbo. Or just stay away from that throttle point.
 
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