Gripper LSD - experiences?

Discussion in 'Track Prep & Tech' started by daNpy, Oct 3, 2022.

  1. daNpy Forum Member

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    Hi,
    Does anyone have experience with limited slip differentials from Gripper?

    I am looking for a LSD to put in the 02A gearbox (to be fitted in the winter), and the Gripper diff with plates has some advantages over torque diffs like the well known Quaife.
     
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  2. Savagesam

    Savagesam Moderator Staff Member Moderator

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    From what I’ve heard, angry!

    I believe Nigel Pinder has a gripper LSD in his Mk2, head to his blog
     
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  3. GVK

    GVK Paid Member Paid Member

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    They do clatter about at low speed manouvereing (sp?) but if just a track car fine.

    Depends what sort of thing you can put up with if used on the road.
     
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  4. Jon Olds Forum Junkie

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    Got a new one about to go into a mate's 020. For a loose surface application, probably ideal. On your 'daily'/
    trackday car, probably not.
    Will let you know the outcome
    Jon
     
  5. daNpy Forum Member

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    It's for my trackday car indeed.
    As it doesn't pass the yearly inspection anymore, road usage is not a problem [:D]
    @Jon, looking forward to hear why (not).
     
  6. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Folk who run a plate diff are usually very good drivers or racers, who found an ATB dfff was no longer fast enough into a corner for their driving style.
    So they put up with the compromise of such a diff, to explore their talants on track.
    If you are slow on track, fitting that part willl not help.
     
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  7. daNpy Forum Member

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    Define slow :p
    I can overtake BMW 325i's between 1980 and 2010, unless they're on slicks or a professional driver is in there (I still have to mount my slicks... ;))

    I was looking for a plate diff on the technical perspective, I understood (correct me if I'm wrong) that an ATB diff is the one with comprises, i.e. if one wheel has (almost) no grip, the LSD operates as an open diff, where a plate diff works all the time.
     
  8. TonyB Paid Member Paid Member

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    Gripper are good, sponsored me in the past. You can talk to them direct for advice and service etc.

    A torque biasing diff is great for road and track day use as its almost fit and forget, where as a plate diff (like the gripper) needs regular servicing and the preload re setting. Thats not a gripper thing, its a plate diff thing.

    The ATB (geared) diff is gentle in use and lock both wheels up most of the time when required so a big step forward over an open [std] diff, also the ATB diff drives much like std, you wouldn't know its there. With a plate diff, the quick way to drive it is drive in to the corner faster than you think you should and just turn the wheel and apply power, the diff will pull you round, if you don't commit, they tend to run you wide. An ATB won't pull you out of a corner like a plate diff can.

    A plate diff can be very snatchy and can pull the wheel out of your hands if you don't concentrate. They are very adjustable for different situations and its a bit of a black art getting them right. If set tight then they judder and creak when turning at slow speed and the car can jump about a bit. However you can set the pre load lighter, and then they are more refined, but not ultimately as fast. The ATB's are pretty much nonadjustable, although you can shim them for a bit more preload (they should have a little as std) but that wears off quite quickly, some come with more preload than others, and are marketed as such.

    The issue for racing with a diff like a Quaife ATB is as its a torque biasing diff so it need torque [load] to transfer the load and work. If you lift a wheel there is nothing to transfer so no drive, for track days and road no big deal the wheels are on the floor almost all the time, for racing wheels are often in the air, so you still want drive as tenths as a seconds count.
     
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  9. daNpy Forum Member

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    Thanks for the extensive explanation Tony!

    Does a plate based LSD need adjustments for each track or can you get round with a more 'basic setting' (when you're happy, you're happy).
    For instance, Assen and Zolder, both relatively close for me, are two totally different tracks. Zolder is short and twisty, Assen has more straights and some high speed corners.
     
  10. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Slower around a track than TonyB who is a racing driver.
     
  11. daNpy Forum Member

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    Ah yes, definitely.
     
  12. Savagesam

    Savagesam Moderator Staff Member Moderator

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    I’m a racing driver. I just race grannies… TonyB may also race grannies, in Tesco…
     
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  13. HPR

    HPR Administrator Admin

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    You can use a basic setting ... ramp angles 25/45 or 30/60 ( Power on / Off trottle - brake )
    25 or 30 degree ramp angle > a less steep angle allow the cross pin climb the ramps easier... so the cam plates go outward to load the clutch pack more

    For deceleration - off power - brake > you dont want much lock while braking and want to get closer to an open diff feel .... this can be as much as 80- 90 degree ramp angle
    As base setting 30 /60 and not to much preload ( to let the ramps work ) works fine on most circuits ....including Zolder, Assen, Zandvoort....
     
    Last edited: Oct 5, 2022
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  14. PhilRyder

    PhilRyder Paid Member Paid Member

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    Very interested in this as we want to do the same but having read this thread not with a plate diff.
    Is this something you do yourself or have done at a garage (appreciate you are in NZ)?
    To service a diff (apparently Quaife need this?) does the box have to be stripped down to the same level as when fitting it in the first place?
     
  15. TonyB Paid Member Paid Member

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    As per above its a mix or ramp angles and pre-load. I mostly race hillclimbs and sprints, so in the UK that dictates a set up mope like a tarmac rally car than a circuit racer, rally cars seem to use more pre-load than circut racers generally. Pre-load seems to be a very personal choice, and from what I can tell the more pre-load you use the more aggressive you have to be with the car to get it to turn......but the greater the benefits when you get it turned!

    To start as per Hugo above and I'd go maybe 40lbs/ft pre-load on the circuits, I've run them as much as 80lbs sprinting/hillclimbing, but unless you force the car in to the corner and really force the throttle on coming out the diff will run you wide when set tight. As ever tricky to always feel the results of changes like this, but no doubt once you have faith in the diff you push far harder than you feel comfortable with and rely on the diff to get you our of certain disaster in your mind lol. After it becomes normal, and you are quicker :-). Maybe psychological though, just got you to drive faster to stop the understeer, so wasn't really any faster.......but in competition that's a result, but for trackdays etc. better to have an easier diff to live with so less is more.

    When I've spoken to Gripper about pre-loads they conform that customers specify all sorts of ranges for different disciplines, so as suspected very much a personal thing, and probably linked to driving style in my experience. Someone who doesn't like pushing on and driving past their perceived limits will probably not like a tight diff and go slower as a result of not getting the diff to work, where an aggressive drive would love it and go faster, and visa versa.

    That's my personal understanding anyway.
     
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  16. HPR

    HPR Administrator Admin

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    Another variable setting is the number of friction plate sides working....
    Altough in most fwd gearboxes the diffs dont have much space to house many friction plates when compared to rwd rear diffs
    70 -80 Nm when setup to get about 50 Nm after some wear...

    Back in the day a Gleitstein diff.... which is infact a locker that is on/off ... and it needed strong arms and the car wanted to go straight on under power on
    So it needed brake deep into the corner and ( very ) late aggressive turn-in and pull a straight line trough the corner
    Its quite an awkward driving style, but its fast.... you see it also in BTCC... but not to recommend for trackday use as there is no room for error...

    Basically with a plate diff with much preload it ( can ) end up in a similar way... and get understeer... unless you force it into the corner ( as Tony said )
     
    Last edited: Oct 5, 2022
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  17. daNpy Forum Member

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    Good info lads, much appre ciated!:thumbup:
     
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  18. TonyB Paid Member Paid Member

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    Of course the diff settings also dictate the suspension settings....and then it gets even more complicated!

    But the theory touched on above holds true...... that is what is ultimately the fastest setup is also often the most difficult to get the most from and all but the very best are better using a more complaint and less hardcore set up as they will ultimately go faster with what is technically a slower setup....we are not all born driving gods despite what we may think lol. So you have to sift through the data as what might be fast for a very experienced racer might be virtually undriveable for a new club racer.

    We see examples of this theory in UK hillclimbing and sprinting (different in Europe where the courses are longer and faster and more flowing more like circuits generally). Whats we see is that a 400F and 300R (lbs/in) set up is a good baseline for hills, where as a circuit car might be 600F and 800R. Much heavier and biased the opposite way. This set up would be very hard to drive quick on a hill as you get two practice runs and two timed runs on cold tyres, where as on a circuit you get multiple practice and race laps as well as tyre warming laps, so you can work with a much narrow range. So you need a very compliant car on the hills so you can feel it under you, and much narrower range is more acceptable on a circuit.

    Just worth thinking about when you are gathering data.
     
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  19. HPR

    HPR Administrator Admin

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    On circuit you can have the rear lively as long you are on trottle , the rear will follow even when it steps out quite much
    But never go off trottle as this mostly result in spinning out ....For sprint racing its OK and its quite demanding on the driver

    For endurance racing and trackdays a well balanced, more neutral car will do good laptimes without much effort, by drive proper trajectory lines and its far more forgiving...
     
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  20. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    HPR is near your side and is very familar with both of those tracks and with VW Motorsports parts in general.
     

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