How restrictive is the breather filter AFTER you've got it clamped over the open DV port?

As Cutic said, the air is diverted to keep the impeller spinning, but there's another process taking place besides using the excess boost to "push" the inlet side of the impeller. When you lift off the gas to shift, the throttle plate slams shut & all the excess boost gets jammed up against it. If you don't relieve this pressure, it will almost instantly "back up" all the way to the impeller. This unrelieved pressure will dramatically slow the impeller (as it tries to push its way past the turbo & into the low pressure ductwork) & creates excessive sideways loads on the bearings. This is why a BOV works in most situations. The air has already been thru the AMM, & the relieved pressure allows the impeller to spin freely even if it's not being directed back around for a second or third time.

My question about the breather filter relates directly to the speed with which this excess boost is relieved. If the filter's too restrictive, it may be affecting the free-spin of the impeller, as well as affecting other recirculation-dependent systems or sensors. (Are there any other sensors? I don't know.)

This GFB FAQ has some good info in it. The "... I can't vent a BOV ..." & "... fluttering, chirping ..." Q&As are relevant to this thread.

posted by 216.160.177...

GFB BOV FAQ

• Info needed on BOV, LH 2.4, Nathan Pflaum , Tue, 20 May 2003 11:17:29
  • Thanks guys, but I think it's going to be the Hybridn/m, Nathan Pflaum , Wed, 21 May 2003 11:13:40
  • Re: Info needed on BOV, LH 2.4, Cutic, Tue, 20 May 2003 19:57:45
    • Re: Info needed on BOV, LH 2.4, Nathan Pflaum , Tue, 20 May 2003 21:07:49
      • yup..., Cutic, Wed, 21 May 2003 00:02:33
        • Its still vented to the atmosphere....., SteveW, Thu, 22 May 2003 21:04:47
          • Well my problem, Nathan Pflaum , Fri, 23 May 2003 09:44:05
            • Trust me on this..., SteveW, Sat, 24 May 2003 09:42:14
          • Doesn't make sense ..., Greg Netzner, Fri, 23 May 2003 08:01:41
        • Which brings up another question for Nathan, Greg Netzner, Wed, 21 May 2003 09:10:02 <-- Viewing This Message
          • You bring up a good point, Nathan Pflaum , Wed, 21 May 2003 10:54:54
  • Re: Info needed on BOV, LH 2.4, steve88sis, Tue, 20 May 2003 19:08:30
    • Yup, car dies. n/m, Nathan Pflaum , Tue, 20 May 2003 19:10:34
  • could you rig up a potentiometer, Trev, Tue, 20 May 2003 12:57:27
    • What about a RRFPR?, Nathan Pflaum , Tue, 20 May 2003 17:57:09
    • Re: could you rig up a potentiometer, Tyler, Tue, 20 May 2003 13:11:50
      • But if you have too much fuel, Trev, Tue, 20 May 2003 15:22:28
        • But you can't counter it with more air ..., Greg Netzner, Tue, 20 May 2003 15:43:50
          • hybrid BOV/BPV, Nathan Pflaum , Tue, 20 May 2003 17:55:06
            • Re: hybrid BOV/BPV, ckpaden, Tue, 20 May 2003 22:51:00
              • Re: hybrid BOV/BPV, Nathan Pflaum , Wed, 21 May 2003 10:44:29
          • Breather filter over stock vlave hole..., Tyler, Tue, 20 May 2003 15:55:16
            • Air Loop, Greg Netzner, Wed, 21 May 2003 08:34:58
              • Re: Air Loop, Tyler, Wed, 21 May 2003 19:20:36
  • Re: Info needed on BOV, LH 2.4, Tyler, Tue, 20 May 2003 11:22:53

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