Can you hear your turbo bypass?

Discussion in 'Fiesta ST Chat and Discussion' started by WScottCross, Jun 5, 2014.


Can you hear the turbo Bypass?

  1. Yes

    33 vote(s)
  2. No

    3 vote(s)
  1. WScottCross

    WScottCross Well-Known Member

    I can definitely hear my turbo spool and especially bypass when shifting. Some folks can't hear it. Can you? What is your setup if you can?
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  3. moshaholic2

    moshaholic2 Active Member

    Yes I can.

    mountune induction kit
  4. Kevin R

    Kevin R Member

    Only if the windows are open :)
  5. Firesail

    Firesail Active Member

    Yes I can. Full mountune induction kit w/ induction hose. I want to get the mTune w/ MP215. I do have Cobb AP w/ 93 octane tune.
  6. MasterPooBaa

    MasterPooBaa Member

    Stock setup here.
    Yes (Just) if i concentrate hard with windows up.
    Better with windows down.

    Ditto with the turbo spooling up and applying boost. Its a very rewarding sound. :)
  7. psylentknight22

    psylentknight22 New Member

  8. dislegal

    dislegal Member

    Yep, sure can and it doesn't matter if the windows are up or down. Stock setup and I was completely thrown when I first drove it and heard it!
  9. BRGT350

    BRGT350 Well-Known Member Staff Member

    I could hear it with the factory intake, but had trouble getting the sound to show up on film when we were recording for the Fiesta Movement. The ST I drove in Brazil seemed to have the loudest turbo bypass of any ST I have heard. That one wasn't a production car.
  10. jimclark

    jimclark Active Member

    WScottCross, dislegal, BRGT350, others: could you guys please describe the sound you're hearing, and when you can best hear it? I'm chasing an extra couple of sounds that may or may not be related. Techs at the dealer are less than helpful thus far. It might be embarrassing if the sounds that are bugging me are all turbo-related, but I would sleep better at night not worrying about the baby. :bucktooth:
  11. BRGT350

    BRGT350 Well-Known Member Staff Member

    Pssssssshhhhhhhh when you lift off the accelerator. I noticed the sound when in 4th gear about 40mph when the throttle is opened and closed quickly. As soon as the throttle plate closes, you hear the psssssshhhh sound. If you are next to a guard rail, trees, parked cars, or a building with the windows down, it is very noticable. When I went to record the exhaust sound of the Fiesta Movement ST, I followed a route that had nothing near the road to bounce the sound off of, and could not get the bypass valve sound to show up on the video. When I was driving the ST in Brazil, the road was lined with dense trees and the sound could be heard very clearly.
    dislegal likes this.
  12. dislegal

    dislegal Member

    Yep BRGT350 has it spot on, I hear it mostly shifting into 4th and 5th. Feathering the accelerator at quite a few revs in 3rd I can trigger the noise almost on command. I'll see if I can get a recording of it for you.
  13. jimclark

    jimclark Active Member

    Perfect! Thanks, guys. I believe that's exactly the sound I hear that I was thinking of as "turbo spool/spin-down". I see that bypass is the preferred term. Good. Unfortunately, that still leaves me with the sound(s) (primarily, at least, a single sound) I'm hearing, which seems to come from the same side of the engine bay, and is heard in the same RPM range (typically, though slightly variable, in 2-3K range) in all gears (best in lower gears, as there is lower ambient noise). It is variable in its intensity, at times being fairly easily discerned, at others difficult to make out. The sound reminds me of the sort of whistling sound that air can make rushing through a cracked-open window. It does not occur with the car in neutral and the engine revved. When it's fairly easy to hear, as it was yesterday evening, for instance, I can get it to become more or less continuous if I can run the same RPM under the same load (as, for instance, on a flat stretch of road, constant speed, constant RPMs of, say, 2.5K) for a bit (up to 5-10 secs). It's driving me just a little batty.
  14. BRGT350

    BRGT350 Well-Known Member Staff Member

    hmmm, so the sound is load dependant. I was thinking the sound symposer tube, but that would make the noise at all times. Can you hear it from outside the car when it drives by?
  15. jimclark

    jimclark Active Member

    I've not had the chance to listen from outside the vehicle. (Wife doesn't drive manual.) I've been told by one ostensibly reliable observer that he could hear it, though it wasn't loud.
  16. jimclark

    jimclark Active Member

    And because it's variable in intensity--so much so that when I took it to the dealer, in fairness even I had a hard time making it out, yet at other times even my wife readily notices it--I have a hard time classifying it as purely incidental/normal. Especially as two weeks ago I'd never noticed it. Combining all these factors--obviously related to mechanical function, load-dependent, variable intensity, and new--it's in the category I have to call abnormal, and potentially indicative of malfunction of some sort. (I'm obviously hoping that any malfunction is mild and of no consequence.) Thus, my increasing obsession with the thing.
  17. joker96

    joker96 Member


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  18. eRic

    eRic Active Member

    we can really hear it with the Green air filter. ask BRGT350 :whistling:
  19. limbo

    limbo Active Member

    Yes I hear it - bone stock
  20. BlueBomber

    BlueBomber Active Member

    Injen I heard it and every other car close by heard it - Stock, you can hear it sometimes with the windows down.

    Stock with a modded lower airbox and high flow filter, you hear it more but still fairly subtle.
  21. No induction modifications. At lower RPM's, floor it briefly and lift off, gives a nice whossshhh.

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