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Quattro differences ?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by markm3006, May 11, 2012.

  1. markm3006
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    markm3006 Member

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    Can someone explain the difference between the A3 & A4 types of Quattro 4WD systems :sadlike:
    Is the Torsen better than Haldex etc etc
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  2. a6_chris
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    a6_chris Well-Known Member

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    Torsen is better but only found on A4/5/6/7/8, Q/5/7, R8 and maybe Q3?

    From my knowledge, Haldex is actually a clutch which engages the rear wheels when the front looses grip where as the torsen is permanent 4wd.

    Someone with better (and probably right!) knowledge of the systems will be along shortly ;)
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  3. Ads
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    Ads License to drive

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    Torsen is permanently four wheel drive. Haldex is mainly front wheel drive until it starts to loose traction and then drive gets sent to the rear wheels also.
    Torsen is generally seen as proper four wheel drive, but Haldex still does a good job because when needed the rear wheels spring into action very quickly.


    EDIT: Yep, what he^^^^ said.
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  4. MartayMcFly
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    MartayMcFly Well-Known Member

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    iirc, Torsen is "all wheel drive" and Haldex is "four wheel drive". That doesn't really clear it up but basically a transfer box send some power to the front and some to the back in AWD, where as the 4WD system sends it all to the front until they spin at which point it lets some go to the rear. It's the difference between passive and permenant four wheel drive.

    Think of it as Haldex is fwd with the back-up of rears when needed, but Torsen is 4wd and the power shifts depending on grip (and a couple of other things, like steering angle etc).
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  5. S3Alex
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    S3Alex Rarely neutral

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    Wiki is your friend....
    Torsen - Wikipedia, the free encyclopedia
    Haldex Traction - Wikipedia, the free encyclopedia
    The thing is that one is a proper diff(the Torsen or other torque sensing diffs such as the Quaife),and will allow much wider torque splits than the Haldex,and the Haldex has often been called a "part-time" 4WD system,which only allows a maximum 50/50 split.
    The Torsen diff couldn't apprently be squeezed into the transverse mounted engine/gearbox of the A3 series,hence the Haldex electrohydraulic clutch is used instead.
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  6. MartayMcFly
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    MartayMcFly Well-Known Member

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    Seems we are all agreed then. :thumbsup:


    Also, related little fact:

    S3s say "quattro", but are actually the VW system know as 4motion (haldex), while Passat 4motions have a proper Audi-spec quattro AWD system (torsen).
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  7. S3Alex
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    S3Alex Rarely neutral

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    The Haldex has been used in rallycross applications previously,with adjustable mapping,but it is limited in terms of torque split,whereas a torque sensing mechanical diff can have different torque splits such as 75/25 or whatever according to the biassing ratio.
    Some torque biassing diffs can feel a bit "snappy" in use,and can give you a bit of a shock when you use one first,but the ability to direct torque to whichever wheel has grip is quite something.
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  8. quattro81
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    quattro81 All the gear.. No idea

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    Torsen is not "better" than haldex.. At least not the last two generations of it anyway.. They are different systems with drawbacks to both.. If haldex was no good it wouldn't be on cars like the Veyron and Lamborghini aventador.. The new version does not wait for wheels to slip- it is preemptive.
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  9. S3Alex
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    S3Alex Rarely neutral

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    Nicely put....both have their good and bad points,and neither is perfect,but if you want more than a maximum 50/50 split,you need something other than the Haldex,whereas the Haldex can in some cases be more user-friendly,and need not be permanently engaged.
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  10. markm3006
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    markm3006 Member

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    So for normal road driving the Haldex would appear to be a good enough system.
    Cheers for the quick replies guys, as you can tell this is my first A3 Quattro, but it seems more refined than my previous Subaru Impreza's drivetrains. :cool:
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  11. MrLapou
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    MrLapou Well-Known Member

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    Thing I noticed with my 2009 A3 Quattro is, when taking off with normal traffic acceleration from standstill the back of the car does not 'squat down' like FWD only cars.
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  12. markos72
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    markos72 Active Member

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    Well I've learned summat today-;)
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  13. murran
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    murran Active Member

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    id rather have a mechanical system that doesnt/cant wear out.

    you dont see any 4wd/4x4 related threads in the a4/6 sections saying its lost drive to the rear or locked up and dragging a back wheel round corners.

    torsen just works.
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  14. S3Alex
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    S3Alex Rarely neutral

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    They both work,in different ways.

    The stock Haldex though is way too slow,and biassed towards FWD,so what you need is the race controller,which removes all of that,and allows you to use it in stock,sport,and race modes,with the latter remaining engaged under braking as well,and also preloads the diff much quicker.

    Totally different feel from the stock mode.

    Oh,and mechanical diffs can wear out......all of them require maintenance,and if you try,breaking a diff,electronic or mechanical,it doesn't matter.
    The Haldex on mine has dealt very well with 440-500+bhp,so i would say it's as robust as any mechanical diff I've used.
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  15. OVRA3
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    OVRA3 Active Member

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    Bit of a thread hijack but Alex is your S3 one of the quickest in the uk? Sounds awesome...
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  16. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Haldex cars don't eat rear tyres like torsion tends too... the gen 1 haldex on my 8L S3 is a bit agricultural but as Alex has said you can get uprated controllers... best of both worlds then...

    Haldex needs proper maintenance though which is getting neglected quite a bit it seems on the 8L's at least these days... dunno what the intervals are on the 8P's but if not kept up the plates will stick..

    Que all the 'proper quattro' comments from the A4 boys lol...

    <tuffty/>
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  17. S3Alex
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    S3Alex Rarely neutral

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    That I don't know.....I've never really been into drag runs for my cars,but I do enjoy the performance when it's moving.

    I don't want the gearbox wrecked,so i tend not to!
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  18. quattro81
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    quattro81 All the gear.. No idea

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    :yes:

    Performance controller (mated with the correct suspension/arb etc) is one of the best mods I EVER bought. At the end of the day, the system is setup as stock to be safe primarily. As mentioned in many previous discussions :) FWD has much more predictable driving characteristic (understeer!) for the novice driver in a loss of traction situation..:thumbsup:
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  19. quattro81
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    quattro81 All the gear.. No idea

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    It does when you use the launch control on the DSG:cool:
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