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Thread: Deceleration exhaust burble

  1. #41
    Join Date
    Apr 2012
    Location
    South Perth, Western Australia
    Posts
    400

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    Would've liked to hear that BMW with the original stock exhaust, but in the Sport+ Mode that the 2nd part was done in.
    I think you're right in saying the tune effected it more than the exhaust - where the exhaust was just changing the tone, adding depth, but not responsible for the burble itself.

  2. #42
    Join Date
    Feb 2010
    Location
    Warranwood, Victoria
    Age
    35
    Posts
    1,546

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    This is mine with a stock downpipe and corksport exhaust with the first muffler/resonator removed.


  3. #43

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    Quote Originally Posted by lup15 View Post
    alright, this will become a repository of burbling exhaust videos lol
    @rayd any further developments to your tweaking? I'm almost certain now that the burbling is mainly due to the tuning, although the exhaust system will influence the end sound.

    I am curious as to what the effects of different methods in tuning will have on the burble and will keep researching. However, these seem to be the main tuning variables:
    a) retard timing only
    b) make over run AFR very lean
    c) combination of A and B
    d) enable over run fueling (apparently injectors are shut off on over run)
    e) combination of A-D

    I've also searched youtube for an MPS with this but couldn't find any, which further points to that it is in the tuning.


    Sorry didnt do much more testing - i've noticed that during deceleration the timing and AFR's dont follow any specific table in ATR, which suggests there is another specific table for overrun which isnt uncovered as of yet.

  4. #44

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    Quote Originally Posted by Bakis View Post
    This is mine with a stock downpipe and corksport exhaust with the first muffler/resonator removed.
    Thanks Bakis. I can hear a slight burble on yours, but its only on occasions. The burble I am after is quite consistent as soon as you back off the throttle and it will burble down the RPM.

    Quote Originally Posted by rayd View Post
    Sorry didnt do much more testing - i've noticed that during deceleration the timing and AFR's dont follow any specific table in ATR, which suggests there is another specific table for overrun which isnt uncovered as of yet.
    all good, I appreciate you even trying this. when I first found (through googling) the over run injector options in the Cobb AP manual, I didnt realise it was for the subaru. I checked out the mazda accesstuner manual and there's no mention of it

    I might send an email to Cobb to see if they know what map the car uses on over run and whether they plan to add it to the list of tables in ATR

  5. #45

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    Anyone else achieve the glorious burble from this thread, and upload?

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