Quaife ATB Differential
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I value your opinion, but it's not what my circle of friends tell me (including pro racers and team engineers). This isn't a criticism, but we should be careful to keep our comparisons straight. It's fine to like this diff, and I do too. It just isn't regarded as the ultimate setup (said, fully understanding most of us don't require that). A good clutch type is preferred in racing circles; this is a great street setup and probably where I'll start -- because I don't have a choice, yet.
I'm envious and really can't wait to do something for my open diff!
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Do you know the reason the clutch type is preferred by racers? Is it a strength issue?
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I think it comes down to the ability to tune, easy rebuilds, and strength. Plenty of subjective "feel" stuff, too. Most of my cars have used Torsen (which is tops!) in RWD or AWD setups. A few cars have used simple viscous couplings (meh) and that's most common. OEMs have to worry about long term durability and stuff that's more about passenger car compromises rather than track performance.
FWD is one of those funky compromises, but here we are!
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I can understand the "racer " point of view on this, but I sure hope when I upgrade to an LSD I won't ever have to crack the case again to tune it or rebuild it. That's probably just wishing and depends a lot on how hard I use the car. So in my case I would think a gear-type unit is better ... more consistent for a longer time. The question I have is will Torsen be building one and will it be substantially different/better than the Quaife? I am seriously considering the Quaife at the moment.
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That's a very reasonable outlook. I definitely don't want to badmouth Quaife -- many people are very happy with them. I don't have any personal experience with them. As mentioned in other posts, I may get one too. I know that it will be a vast improvement (even though I have friends that tell me not to settle for it).
I do know Torsen and other kinds of LSD systems. I also get an earful from my circle of friends about other options -- I've tried to be clear on what my opinions are first-hand, and the stuff that I share based on trusted opinions.
My absolute favorite gear-type LSD is Torsen; I mean the actual brand, not "equivalent"! I think that if Torsen did make one, it may cost quite a bit more. Again, a different type of system. They're comparable in function, but different in how they go about it. In short, the Torsen behaves like an open diff until it's needed (when the torque imbalance actually occurs). I've had Torsen in sports cars and rear-ends for offroad applications. I'm a big fan.
Edit:
Oh yeah, one nice advantage of clutch type systems (excludes all but one kind of Torsen)...
You get help when you put a wheel in the air! Gear-type systems essentially assume both sides are down to function properly.
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That was one question I had: how different are the Torsen and Quaife? I assume they both use patented technology, so must be some substantial difference in methodology. I had good luck with upgraded clutch diffs in my Mustangs, but that's a vastly easier unit to get at and maintain
Also don't some units like the T2R have a preload so they can handle a wheel in the air?
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They each have their secret sauce. The equally short answer for Quaiffe is that they choose to implement torque balancing progressively -- it's never "open" like a Torsen. They can arrive at similar final TBR #s. Yeah, the T2R was the exception I was thinking about from Torsen -- but have never run one personally. It does use a preload clutch for this very reason.That was one question I had: how different are the Torsen and Quaife? I assume they both use patented technology, so must be some substantial difference in methodology. I had good luck with upgraded clutch diffs in my Mustangs, but that's a vastly easier unit to get at and maintain
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No track time yet, but I hope the BC coilovers minimize the chance of lifting a drive wheel. I also have that extra set of 5k rear springs if it needs more rear roll stiffness.
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Even with my BC coils I still had a lil tire lift and spin on corners never tracked the car in stock form so can't say if they are different or not but the adjustable dampening is noticable soft for DD then firm them up good for track day ... Have yet to track the car since the LSD was added but I do know i will have to pracrice left foot braking if the wheel in the air becomes a issue .. Which I doubt the way I drive LOL Still for cone killing I can see this as nothing but gravey ..
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When I first read about LSD on the FiST they were saying that this would be one of the advantages of the TVC with Ford, it SHOULD apply brakes to the wheel that's off the ground, which is something that the LSD wouldn't be able to compensate for.
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From what I understand about the Quaife ATB LSD is the wheel braking would play into the way this LSD work. And from what I have seen and felt at the track with ESC off the rear wheels work to make the Torque Vectoring work kinda neat you can feel it nibbling at the brakes to help you corner..
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All you need are Two new bearings and one or two (your choice One for sure) axel seals. And the proper size shim from Ford. Once I get the bearing delivered to see if a local source can be found for the proper bearing since ford has not priced our exact bearings.
I'll put together a list once I get everything. Seals are about 15$ , shims are priced goofy anywhere from 3 to 50 $ depending on size needed. Bearings should be around 50 or so once sourced local maybe less .. Then a tube of loctite gasket maker for the case. Like I said remind me if I get distracted and I'll make a list for you later this week when bearing gets here.
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I found what I was talking about Rod:
http://fordstnation.com/focus-st-performance/8068-quaife-atb-tvc-mystery-solved.html
Quote:
"Actually, the combination of an ATB and TVC is beneficial, as the ATB cannot bias torque in the case where one wheel has low/zero normal force (axle torque), as is the case with weight transfer causing a lifted or near-lifted wheel (or riding curbs / dropping a wheel). In this case, TVB brakes the unloaded wheel, permitting again torque transfer via the ATB."
http://fordstnation.com/focus-st-performance/8068-quaife-atb-tvc-mystery-solved.html
Quote:
"Actually, the combination of an ATB and TVC is beneficial, as the ATB cannot bias torque in the case where one wheel has low/zero normal force (axle torque), as is the case with weight transfer causing a lifted or near-lifted wheel (or riding curbs / dropping a wheel). In this case, TVB brakes the unloaded wheel, permitting again torque transfer via the ATB."
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Yup read that when PCA posted it it was kinda what we were thinking when we got into this install ..
Also read on other forums about left foot braking being a way to help the car with a ATB LSD. Though those cars did not have TVC
I would hope the TVC is fast and linear enough to not cause locking and unlocking of the diff during entry, mid or exit of the corner, that could cause a serious upset and could be even dangerous. I will be watching for comments on this.
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If I could find a clutch type LSD that would fit without to much trouble I would sent it off to have progressive ramps cut, get some good disks and plates, REM finished.......
Or better yet, get an OS Giken like I had for my forged LS powered E36 M3 track car I was building, $$$$$ but work incredibly well.
For now, that I am retired, I am waiting to hear back from PG but watching the info on the Quaiffe as it might work incredibly well with the TVC.
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If I could find a clutch type LSD that would fit without to much trouble I would sent it off to have progressive ramps cut, get some good disks and plates, REM finished.......
Or better yet, get an OS Giken like I had for my forged LS powered E36 M3 track car I was building, $$$$$ but work incredibly well.
For now, that I am retired, I am waiting to hear back from PG but watching the info on the Quaiffe as it might work incredibly well with the TVC.
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354 Posts
This is called 'old 300ZX syndrome' with the old VL50 Viscous Limited Slip Diff, ha!
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