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Another anti roll bar question

mercules Jul 18, 2018

  1. mercules

    mercules Active Member

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    Couldn't find anything for my exact question so hopefully someone has done this and can shed some light.

    I have a S4 with sports diff and the rear ARB is 16mm from what I've read. I want to get a uprated one but they come in twos and I already got a H&R front on a good price off a member from here.

    My question is has anyone swapped the 16mm one for the non sports diff 21.7mm one? I can pick them up cheap £40 used with everything but new bolts.

    I saw the 034 rear but I'm not paying £300 for a metal bar unless it's night and day over stock S4 21.7mm one.

    Thanks

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  3. Dippy

    Dippy Well-Known Member Team Monsoon Audi S5 Black Edition

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    I can't answer the question but I wonder why our cars have the 16mm bar. I can only imagine that it is because the sports diff prevents a thicker one being fitted?
     
  4. mercules

    mercules Active Member

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    I've read it's because it makes comfort mode more soft?

    I've just bought this morning a RS5 rear sway for cheap so trying it out. Could prove a nice cheap mod for us "smart" savers.

    Someone said RS5 22.5mm fits a S5 and then someone else said a stock S5 21.5mm fits a S4.

    See where I'm going

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  5. forty3

    forty3 Active Member

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    034 arb made a big difference to my S4 when pushing hard through long bends. It definitely helps to tame the cars desire to understeer.

    I don't have sports diff tho so not sure what difference, if any, an uprated one would make on your car.
     
    mercules likes this.
  6. mercules

    mercules Active Member

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    I have a friend who is lucky enough to have had a new shape merc C63s and he can drive. We went for a small trip in my car and I took a long corner at very good speeds and he was so amazed I didn't slide out comparing to his Merc that following couple weeks he PX it for a R8 V10 plus.

    He mentioned 50% of the decision was based on the grip you get from AWD compared to RWD. I think anything over 400hp on RWD struggles to put power down in the first couple gears.

    I have noticed driving the S4 on a hard pulls the back does feel like it wants to come out if I can control that a slight bit more I'd be happy. I also wished the super sports seats were more hugging as I find I'm sliding all over the place when driving on twisty roads.

    But then I say to myself it's a near 2 ton estate car sort your life out haha



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  7. Dippy

    Dippy Well-Known Member Team Monsoon Audi S5 Black Edition

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    The p/n for a 2013 S4 21.7 mm rear bar is 8K0 511 305 AB
    The p/n for a 2013 S5 21.7 mm rear bar is 8K0 511 305 AB
     
  8. mercules

    mercules Active Member

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    So if the RS5 bar is said to fit the S5 on Audizine then I'm on to a winner.

    Will update once it comes and I fit it.

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  9. mercules

    mercules Active Member

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    It's here! [​IMG]

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  10. mercules

    mercules Active Member

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    Just confirming 8k0511305s 22.5mm rear bar from RS5 fits fine on b8.5 S4.

    It cost me £60quid from eBay breakers.

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  11. Chets

    Chets Member VCDS Map User

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    How does the handling compare over stock? Is it a noticeable difference on long bends?
     
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  13. mercules

    mercules Active Member

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    I had Eibachs fitted and moog solid front and rear end links at the same time. Although I can't comment purely on the rarb performance the car feels more planted and corners I've taken it made the back less twitchy. Before on stock one I did notice a few times under load cornering you'd get a little twich and the diff would kick in now I've not had it happen in a week since it's been fitted.

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  14. Deckard

    Deckard Member

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    I was about to order a 034 rear sway/arb but Awesome have stopped stocking 034 for some reason and everyone else, including 034 are out of stock. I agree £330 for a bar is a lot lot lot of money but this seems a very popular upgrade.
     
  15. xpoweruk

    xpoweruk S4 B8 Smile Machine Team Ibis saloon Audi S4 quattro

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  16. Deckard

    Deckard Member

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    thanks, I'll call them tomorrow, they have a terrible website :)
     
  17. forty3

    forty3 Active Member

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    Get yourself on the S4 owners group on Facebook. Mark of Brotek runs it and always answers messages.

    The arb is a lot of money but worth it if you want to drive beyond the point when the car starts to understeer as it helps bring the back end around at the point when you'd normally start sliding.
     
  18. Cerbera9

    Cerbera9 Active Member

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  19. jdp1962

    jdp1962 Grumpy Old Moderator Staff Member Moderator TFSI Owners Group Team V6 Gold Supporter Team Tornado Audi S4 Black Edition quattro S tronic

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    Last edited: Sep 11, 2018
  20. GarethS4

    GarethS4 Active Member

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    I have just bought a set of eibach arbs and have been told by several people not to fit the front bar and only fit the rear .what is the reason for this could someone explain please .
     
  21. jdp1962

    jdp1962 Grumpy Old Moderator Staff Member Moderator TFSI Owners Group Team V6 Gold Supporter Team Tornado Audi S4 Black Edition quattro S tronic

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    It depends on what you're trying to achieve in the handling department. Uprating the rear antil roll bar increases rear roll stiffness which, on its own, reduces understeer. Uprating the front-anti roll bar increases front roll stiffness which, on its own increases understeer. Uprating both at the same time will probably cancel out any changes to the level of understeer, but improve overall roll resistance. There may, though, be a stiffer, jigglier ride.
     
  22. Cerbera9

    Cerbera9 Active Member

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    Just replacing the rear roll bar helps turn in and reduces understeer.

    Replacing both keeps the ratio between the front and rear overall increase the roll stiffness keeping the car flatter through sweeping bends etc.

    I installed both front and rear H&R roll bars and i'm very happy with the handling. The front H&R is adjustable so set this on the softer setting which is still stiffer than standard. This way you get the best of both worlds as the ratio front to rear has changed reducing understeer and helping turn in and overall the car is flatter than standard through the bends.
     
  23. GarethS4

    GarethS4 Active Member

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    Really what I’m looking to stop is the way the car feels like em how would you explained it very boaty as in on say a longer corner rolling sort of .sorry I’m not doing a very good job here am I lol.i want it to feel planted with little or no roll without going to the extremes of changing shocks ect as I don’t want it to hard as it’s my daily .the car just moves about far to much when being pushed on a bit .i do have eibach springs already so was hoping the arbs cut out a good bit of that roll I’m on about .
     
  24. mercules

    mercules Active Member

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    I'm much less roll now with both arbs and springs. What tyres you using too?

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  25. Cerbera9

    Cerbera9 Active Member

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    Do you have Audi Drive Select?
     
  26. GarethS4

    GarethS4 Active Member

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    I have 20,s fitted and using 255/30 Michelin PS4S
     
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  27. GarethS4

    GarethS4 Active Member

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    No I don’t have .
     
  28. mercules

    mercules Active Member

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    Ok do the upgraded bars then tyres are good. I've got 19s about to go from PZero (warranty) to PS4s on the rear.

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