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disconnecting haldex - can it cause damage?

Discussion in 'A3/S3 Forum (8L Chassis)' started by quattro1, Jul 22, 2010.

  1. quattro1
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    quattro1 Member

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    ok ive just pulled the haldex fuse and took the car for a spin and it really does drive noticably better! with it working the power would die off at 5k revs and just moan to the redline (suspect it needs another remap!) but now with the fuse pulled, the car pulls very nicely!

    my question is, can i leave it like this or will it cause damage?

    thanks alot
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  2. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    Define how it 'drives' better'? I guess it won't damage it with it off, you just won't have 4WD. So long as the front and rear axles are rotating at the same or similar speeds, I guess it can't damage it.
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  3. quattro1
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    quattro1 Member

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    well like i said, with the 4WD active it would just feel strangled after 5k rpm and massively bog down when pulling away, now, it actually pulls very nicely to the redline so its not just a psychological thing :blink: could this possibly indicate that somethings actually wrong with the system?? i cant seem to find any reciepts for a service of the system which is abit worrying!


    thanks for the quick reply :thumbsup:
    #3
  4. Mpathe
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    Mpathe 1st gear

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    well i did have a switch in it so i could turn it off whenever i wanted to have abit of fun and ive never broke anything (touch wood) so should be ok.
    #4
  5. s3dave
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    s3dave TFSI Hybrid

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    plus you would have to change your user name....:)
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  6. quattro1
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    quattro1 Member

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    haha ^^ :lmfao:

    the switch isnt a bad idea though!! cheers for the quick replies, spot on!
    #6
  7. S3BAM
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    S3BAM Member

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    Absolutely fine
    #7
  8. barters3
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    barters3 Member

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    when my haldex was faulty i did a lot of driving without 4x4, i thought it drove like a bag of poo! the front wheels would just light up off the mark.
    To be honest it has put me off ever owning a fwd car over 200bhp. (unless it had a proper lsd!)
    Does your car have an esp button. If so turn it off, this would definitely transform the car.
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  9. quattro1
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    quattro1 Member

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    nah doesnt have an esp button :sadlike: i do suspect its partially due to how its currently mapped, i bought it on the promise that it had been remapped prior to having a ko3s fitted, ive had doubts from the day i got it that there was any truth in it, it has flat spots and as said with the 4wd enabled it dies after 4.5-5k, doesnt give me any more than 19mpg no matter how i drive it either! ill drive it for a few days and see what actual differences it has made
    #9
  10. Welly
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    Welly VX220 SC Driver :)

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    Hmmm, that doesn't sound right to me at all dude.

    It should pull the very similar in 4WD as it does in 2WD.

    Sounds to me like you have an inherent problem there somewhere, especially with the MPG you're getting.

    Have you had it read for fault codes or the like?
    #10
  11. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    It must be in your head, as the car is 2wd most of the time, and only 4wd when it senses you have lost traction.

    Unless you have a HUUUUGGGEEEEE turbo spooling up at 5k and breaking traction under boost, it should make no difference. It shouldn't however do any harm either
    #11
  12. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    It will most likely be in 4wd mode @5k revs, the Haldex kicks in on throttle position too, and at 5k revs, you are most likely on full throttle.
    #12
  13. 1animal1
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    1animal1 The Clar!! it mouves!!!

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    there was a pdf from Haldex themselves not recommending you go over 30mph with haldex disconnected...reason being is that the parts are still moving regardless of fuse being pulled (you can also lift your handbrake one notch to disengage it)

    personally i wont ever be doing it based on what i have read in the past - google that doc if i were you
    #13
  14. Welly
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    Welly VX220 SC Driver :)

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    I remember reading that now you mention it.
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  15. quattro1
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    quattro1 Member

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    no its definately not in my head it is 100% deffo better in 2wd! the difference is too massive to be a psychological thing! i'll be plugging it back in tonight anyway as i have read the doc mentioned above and dont like the sound of it at all! guess ill just have to wait for the remap and see if that makes any difference, but serioulsy, after 5k it sucks!

    cheers for all the good replies, really helpful
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  16. quattro1
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    quattro1 Member

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    no i havent had it read for any faults, is vagcom easy enough to use? been thinking of trying it myself!

    cheers
    #16
  17. 1animal1
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    1animal1 The Clar!! it mouves!!!

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    Erm ya not mistaking it for the common s3 driving characteristic are ya, tails of not much more than 5k
    #17
  18. barters3
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    barters3 Member

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    it would definitely be advisable to have it vagcom'd before you go mapping it. as stated it tails of above 5k, i dont really feel the need to rev it passed 5k, but perhaps thats just down to my driving style?......
    #18
  19. Danny Cawsey
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    Danny Cawsey Cawsey

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    can anyone tell me where the haldex fuse is?
    #19
  20. 1animal1
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    1animal1 The Clar!! it mouves!!!

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    the fuse board :)
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  21. quattro1
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    quattro1 Member

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    number 31 if i remember rightly lol
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  22. 1animal1
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    1animal1 The Clar!! it mouves!!!

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    or lift the handbrake 1 notch.....same effect ;)
    #22
  23. Danny Cawsey
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    Danny Cawsey Cawsey

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    cheers
    #23
  24. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    If you have ESP.
    #24
  25. b1gdave83
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    b1gdave83 Member

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    lol or open the boot that also switches it off for some strange reason
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  26. S3 TAM
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    S3 TAM Pocket now empty

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    What have you read in the past and is it safe to use the handbrake to turn it off. why would you want to do that anyway?
    #26
  27. scoobyra
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    scoobyra It's not f@cking ORANGE!!!!!

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    Pulling the handbrake up makes the car go into 4 wheel drive mode. Very good for launching at 5k (apparently :p:p:p)
    #27
  28. b1gdave83
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    b1gdave83 Member

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    Pulling the hand brake up turns it off not on :huh:
    #28
  29. b1gdave83
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    b1gdave83 Member

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    I personally don't see why it is a problem considering when you brake it also switches off, the orange haldex controller keeps the 4 wheel drive active while breaking...

    But saying that I have also read the same thing about 30Mph thing
    #29
  30. scoobyra
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    scoobyra It's not f@cking ORANGE!!!!!

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    I'm not sure about that Dave as I read that pulling up the hand brake tricks the haldex into thinking it needs to drive all four wheels, a method we've been using for 1/4 miles for ages.

    If I turn the esp off and lunch the car at 5k the front wheels spin like mad. Pulling the hand brake up makes the car rocket forward without any wheel spin what so ever!
    #30
  31. b1gdave83
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    b1gdave83 Member

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    Yep do a quick search haldex bible, search handbrake in the PDF

    The handbrake switch sends the "handbrake
    engaged" signal to the ABS control module
    J104 and simultaneously to the Haldex con-
    trol module J492.
    Whereas the ABS control module transfers
    this information to the Haldex control unit in
    filtered" form along the CAN bus, the
    Haldex control module also receives the
    information directly from the handbrake
    switch.
    if the signal generated by handbrake switch
    F9 is picked up, the Haldex coupling clutch is
    opened.

    http://www.billswebspace.com/HALDEX.pdf
    Last edited: Sep 10, 2010
    #31
  32. b1gdave83
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    b1gdave83 Member

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    What's interesting is that you turn ESP off first, maybe it's the opposite when you do that. Lol I do some testing in my car later :eyebrows:
    #32
  33. Alex C
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    Alex C Active Member

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    i thought applying the handbrake turns 4WD off cus it doesnt want to drive the rear wheels if the brake is on
    #33
  34. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    Correct.
    #34

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