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4 Aug 2011, 15:37 (Ref:2935846) | #1 | ||
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Gripper diffs
Hi Folks, bit of a techhie question.
I have a gripper diff in a rear wheel drive car running on Dunlop CR65's with about 160hp. Now, I don't know too much about the differences between all the differant brands of diffs availble but I do know I lose traction when exiting tight corners, the inside wheel spins like an open diff for a second or 2 before it finally locks up & then tries to throw me into oversteer. This yr is the 3rd season without any dismantling as I was told the "Gripper" was fit & forget. Is this normal for a Gripper & can I do anything about it? I plan on taking it apart through the winter so their is is the oppotunity of getting it fixed. Any ideas? |
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4 Aug 2011, 15:57 (Ref:2935859) | #2 | ||
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Maybe one for the techie forum, but in meantime...
The only LSD that comes to mind immediately as 'fit and forget' is a Quaife, which is not a plate type. As the Gripper is, wear will surely occur, especially if the car fitted to is prone to lifting inside rear wheel on corners? The symptoms you describe sound more like a fault than just wear, though. I've got at least 3 plate LSDs of different makes- including a Gripper- in cars up to 250bhp and a couple of seasons regular use appears about normal for rebuild. Obviously correct oil is essential and setting preload to suit particular application. I know the Gripper is available with different ramp angles, any idea which you have? |
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4 Aug 2011, 16:01 (Ref:2935860) | #3 | ||
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What's a "Gripper" diff?
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4 Aug 2011, 16:02 (Ref:2935861) | #4 | ||
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4 Aug 2011, 16:15 (Ref:2935865) | #5 | ||
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Could the words "unusually progressive"be a clue to the problem?
It could just need setting up differently for your car. Mike, the Quaife diff you are thinking of is the ATB,it doesn't have plates inside,it has lots of gear thingys instead. And they will spin up the inside wheel if it lifts. |
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4 Aug 2011, 16:20 (Ref:2935867) | #6 | |||
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Quote:
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4 Aug 2011, 16:47 (Ref:2935875) | #7 | ||
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Thanks Robyn, you make a good point.
I was talking to Dan about it at Brands a few weeks ago & his comment without going into too much detail is the Tranx diff can be built to be almost locked solid. Not suggesting that this is correct way forward but mine has been set up 35/65 which I think is the 'tightest' Gripper can go. |
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4 Aug 2011, 17:22 (Ref:2935888) | #8 | ||
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I have looked into this a lot lately as the Auburn diff in my Camaro has given up the ghost and they are not rebuildable. The Quaiffe is similar to the Eaton Detroit TrueTrac http://www.eaton.com/EatonCom/Produc...trac/index.htm (not their Detroit Locker thats different again) and is not progressive. I have come to the conclusion that different tyoes of diffs, Limited Slip, Quaiffe/Trutrack full Detroit Locker or plate diffs like the Eaton Posi I have just bought, the Auburn and one like yours all have their pros and cons and none are perfect for every scenario, I have gone for the Eaton http://www.eaton.com/EatonCom/Produc...iLSD/index.htm. Also none are truely fit and forget even the Quaiffe style, some are more brutal on half shafts especially kurb hopping, some like the lockers will give bad understeer and can be nasty if one wheel hits a wet patch bit like a fully locked diff. I have gone for the Eaton as like yours its rebuildable cheaply and it can be adjusted for different levels of slip. I would suggest yours as has been said above just needs a bit of resetting, maybe stronger springs or whatever if it has those like the Eaton.
Actually looking again I would say the 'springs' on the gripper are the Belview washers maybe they need replacing and or the plates? |
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4 Aug 2011, 17:37 (Ref:2935895) | #9 | |||
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Mr 105- 35/65 sounds like ramp angles rather than preload, which would be in ft/lbs or similar. Preload is how 'tight' diff is before the ramps start their work. If you jack one rear wheel up while other is still on ground can you turn the wheel in air? If you can, you no longer have (or never had) preload. I use a 'tight' Tran-X in one car that had a tendency to lift inside wheel, but that's not to say a Gripper shouldn't be able to do same job. It may be, as Al says, that the Belville plates that give preload have weakened or plates are worn. Maybe time to have a look at it... |
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4 Aug 2011, 19:18 (Ref:2935924) | #10 | ||
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After having clutch slip or inside wheel spinning (or both) at brands the last time i was out,i checked the diff and found very little resistance turning one rear wheel the opposite direction to the other.
I,ve now replaced the clutch plate(4 paddle instead of a 3 paddle)and pre loaded the tranx diff to 50 ftlb. I'll see how it goes at Croft on sunday |
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4 Aug 2011, 19:24 (Ref:2935927) | #11 | |||
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We expect at least a podium with all that..... |
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4 Aug 2011, 21:40 (Ref:2935968) | #12 | ||
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4 Aug 2011, 22:53 (Ref:2935995) | #13 | ||
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I was given a Quaife diff by Michael Quaife many moons ago to see whether it would suit my car and driving style. However as my car was light and picked up rear wheels easily I soon went back to the Salisbury plate type.
You can almost get away with a welded diff (I have on several occasions) on a light car with 'narrowish' road type tyres but can be a bit of a handful in the wet. I understand that F1 cars years back tried solid diffs when they ran those huge high aspect ratio rear tyres and relied on the flex of the side walls during cornering. I always torqued my diffs to 90 ft lbs with washers cut from old oil cans (cheapskate) as when they get hot they are not consistent throughout the race, and finish up with little resistance at the end of even short races. |
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5 Aug 2011, 07:55 (Ref:2936058) | #14 | |
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Is there some Scottish blood in there Gordon?
I've always run a plate diff, have a tran-x and a salisbury, I've always had Dave Longhurst rebuild mine, about once a year (which these days is every other race!) ATB's are for road cars and wrong wheel drive |
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5 Aug 2011, 08:33 (Ref:2936069) | #15 | ||
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As i said there are pros and cons for each type is the conclusion I have come to. I still agree from my research the plate diff is the one we want for RWD road racing.BTW I sent the PowerTrax locker another sort of locker diff which I later discovered may be too harsh for road racing, unopened back to America and good company JEGS have given me a full refund, full marks to them just gotta hope customs play ball now and give me a refund. I now have the eaton plate diff at customs. Also these things especially the Eaton one similar to Quaifes are so much less to buy than the quaife so worth looking into and the company has a good reputation across the pond. JEGS will ship to UK and are a stockiest.
Last edited by Al Weyman; 5 Aug 2011 at 08:38. |
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5 Aug 2011, 18:22 (Ref:2936222) | #16 | |
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5 Aug 2011, 18:28 (Ref:2936234) | #17 | |||
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Errr, it probably would be if I got something more than a blank screen. Is it me? |
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5 Aug 2011, 18:45 (Ref:2936242) | #18 | ||
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it takes a few seconds to load, but I got a 10 page .pdf
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5 Aug 2011, 18:52 (Ref:2936247) | #19 | ||
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5 Aug 2011, 20:06 (Ref:2936295) | #20 | ||
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Being a bit of a detective: Putting your Forum moniker, the phrases '160bhp and rear wheel drive' together, would I be right in thinking you race an Alfa GTA or similar?
If so, and you ever look at replacing the Gripper diff, I can highly recommend the OS Giken diffs for 105 (or 101 in my case) Alfas. Much, much quieter than the Gripper, and very well made. Been using one for 5 seasons of hard(ish) racing, and only now am I thinking of 'tightening' things up a tad now. Don't know if they're available in the UK yet - I bought mine from the US, and Paul Spruell stocks them over there. Not cheap, but a good investment! See: http://tinyurl.com/3v3fcto Charlie at Cloverleaf Transmissions was so impressed when he built my axle, that he wanted to import them... Of course, if my deductions are wrong, and you DON'T drive an Alfa, ignore what I've just typed... |
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5 Aug 2011, 20:17 (Ref:2936299) | #21 | ||
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Yes I had read that before and was part of my research. My mate who has a powerful SD1 have experimented with a few of these and didnt like the Quaife especially if kerb hopping as that article does point out it relys on the wheels being firmly planted on the ground, one of those would probably have done me as I dont tend to cut the corners. Well not much anyhow!
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9 Aug 2011, 16:02 (Ref:2937679) | #22 | ||
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Yes SZ Racer you are correct in your assumptions.
I have bought some bits off Paul Spurell in the past & always found his stuff good. Funnily enough I've just put the phone down on Charlie at Cloverleaf Transmissions, his suggestion was that the Gripper is good for about 3 seasons racing before they needing a re-build including re-setting the pre-load which can be set to what ever is required. Since he built my axle anyway I'll probably go down that route. |
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9 Aug 2011, 23:10 (Ref:2937881) | #23 | ||
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I have a Quaife ATB in my new car, and I must say I was a bit sceptical at first (it came with the car) after reading up on how they work. However, having now raced it in anger, I must say I've been pleasantly surprised. In my car, which is live axle with 300+ in both power & torque, it seems well up to the job. Gives a nice progressive break away, good traction and I haven't noticed any spinning up of inside wheel. Not saying it's necessarily any better than a traditional plate diff - just that it doesn't seem any worse.
I should add that I haven't tried it in the wet yet, and that may be where it comes unstuck - excuse the pun! |
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10 Aug 2011, 15:15 (Ref:2938136) | #24 | ||
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Yes thats what I have read also if one wheel gets airbourne, it has one advantage over a plate diff well more than one, you dont get bits in your oil and you dont need any additive.
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10 Aug 2011, 15:21 (Ref:2938137) | #25 | ||
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Yes Al - just bog standard EP gear oil I believe. And, in theory, shouldn't wear out any faster than a normal open diff, so virtually zero maintenance.
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