Differentials : Quaife or OS Giken Superlock?

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scheherazade
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Differentials : Quaife or OS Giken Superlock?

Post by scheherazade »

Quaife progressive up to ~ 95%
OS Giken progressive up to 100%

Quaife = fixed
OS Giken = preload adjustable, and ramp rate adjustable

Quaife = becomes 'open' if one wheel *completely* loses traction. Still locks a little bit if there is sufficient drag, but a 'wheel in the air' or a 'wheel on ice' would be like open.
OS Giken = least lock you can have is the preload lock. Also locks more if there is at least *some* drag.

Quaife = locks ONLY when there is a torque load on the wheels.
OS Giken = locks on torque load primarily on input shaft. If you 'gun it' fast enough, even with both wheels in the air, if it has to accelerate hard enough, it can still lock.

Quaife = Does not 'push' you through a turn. If you gun it with steering at full turn, you will turn.
OS Giken = If you gun it with the steering at full turn, LSD can 100% lock and can push you forward. (Granted that the progression can be adjusted to be partial, or it can be set to lock at a torque level beyond what your car can do... but still, it's a pusher)


I've read positive and negative things about both
+Quaife has great steering response
-Quaife sometimes goes limp on tight corners and spins inside wheel (the flip side scenario)
+OS Giken locks progressively on a corner exit, and you can modulate it with power (where the Quaife spun a wheel.)
-OS Giken can get solid-axle-syndrome (Granted you could 'adjust' a lot of it out by reducing preload and using a lower ramp, but then you would be making it more like the quaife)

Most of the OS Giken reviews I've read express preference over the Quaife.

I'm no looking at the 'regular' cluch type LSDs because they are just too expensive.

Any opinions?

-scheherazade
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zaxrex
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Re: Differentials : Quaife or OS Giken Superlock?

Post by zaxrex »

Is this for replacing the front diff, or one of the other two?
Patience is the ability to idle your motor when you feel like stripping your gears
scheherazade
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Re: Differentials : Quaife or OS Giken Superlock?

Post by scheherazade »

Rear.

I currently have an open diff in the rear (well, both are open). The traction conrol has active braking, but it's a bit laggy, and it fights you over where you tell it to go.
In winter when I went out at night to dick around in the snow, the TC on would literally try to force you to go straight if it judged that there would be even a small amount of tail-out action. I actually hated it...

I'd like something that won't interfere around town (including brisk off-the-light turns).

But I also want something I can have fun with, like going to an empty wet parking lot + turning off the TC and drifting some circles or figure eights... or even just the occasional oversteer 'fun tap on the throttle' when taking turns (when no one is looking).
(edit #2: I'd also like to track the car, after I have at least 1 oil cooler, wheels, tyres, maybe a tranny cooler and finned diff cover... but that's a ways out.)

-scheherazade


edit :
In 2008, along with the 135i, the 335i's got an 'LSD' program loaded as the default mode for 'traction control off'
It just balances left/right.
So it can take some turns pretty well : http://www.youtube.com/watch?v=LFCB2GvKrVc

However, pre 2008's, and all XI's (they hate awd apparently...) get the old stability program, which is literally 'everything off if you turn off TC'.
Mixed blessing.
- You can not turn off TC and have an LSD-like experience (lulz)
+ At least if you put a real LSD in, you don't have the computer interfere since it's all-off.
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zaxrex
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Re: Differentials : Quaife or OS Giken Superlock?

Post by zaxrex »

Damit, I keep forgetting what kind of car you have... Sorry
Patience is the ability to idle your motor when you feel like stripping your gears
scheherazade
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Re: Differentials : Quaife or OS Giken Superlock?

Post by scheherazade »

BMW 335 XI coupe (E92)
3.0L TT, AWD
Manual, 3.08 final drive
Open diffs front and rear (Mit Der Uber Schtability Kontrol)


Also, the LSD's are :

Quaife = Torsen, helical gears transmit power between L and R wheels. Since they are not straight cut, any load causes the gears to slide laterally into the differential body, causing friction.

OS Giken = Center ring has radially mounted pinions that transmit power left to right. Input torque pulls the center ring around, moving the whole assembly. The center ring has on both sides two plates, that are ramped against the center ring. As the center ring is rotated by input force on the differential body, it ramps against two rings on either side, that pushed the rings outwards to the sides. A series of clutch plates that slide laterally are engaged, and rub against another set of plates that are on the outbound shafts.

Edit : Nice review - http://grassrootsmotorsports.com/articles/whats-diff/

-scheherazade
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complacent
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Re: Differentials : Quaife or OS Giken Superlock?

Post by complacent »

I'd go with the OS Giken personally and use throttle modulation the way god intended it to be ;)

If a tail-happy car like an S2K is happier with that diff - it speaks volumes about the product.
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Re: Differentials : Quaife or OS Giken Superlock?

Post by Sabre »

:popcorn: Been wondering the same question on the STI's :)
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Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
scheherazade
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Re: Differentials : Quaife or OS Giken Superlock?

Post by scheherazade »

Well, I ended up getting the Wavetrac

It's like a quaife, but with an extra friction mechanism to resist if one wheel is up in the air (or just slipping like crazy).


I can't compare diffs, but :

versus open diff w/ stability control on : much less intrusive, much more predictable. Oversteer is very proportional to throttle, and easy to manage. No sudden changes from the brakes kicking in.

versus open diff w/ stability control off : I can actually sustain some overseer. Before the tail would come around for a moment, and then the inside would slip. Afterwords the rotation would just stop. Now with the LSD, it goes as long as I let it (or until I pick up enough speed and the car sticks).


I also had my alignment changed.
More (absolute) camber/caster up front, and less in back.
The rear also got some toe-out, and I was raised 3/4".

I like to take a quick right/left here coming from wellington.
http://maps.google.com/maps?f=q&source= ... n+Rd+&z=16

In the past the front would push through the turn a bit, and I'd get some "ssshhhhhh" noise from the nose.
Now I can feel the car rotate better and it's quiet, given the same speed.

More body roll with the larger height though :-\. I'll prolly lower it down again once I get different tyres and I know how much room there is for the spring perch.


Anyways, I'm enjoying the changes :D


-scheherazade
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zaxrex
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Re: Differentials : Quaife or OS Giken Superlock?

Post by zaxrex »

Thanks for the good technical deets.
Have fun and stay safe.
Patience is the ability to idle your motor when you feel like stripping your gears
scheherazade
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Re: Differentials : Quaife or OS Giken Superlock?

Post by scheherazade »

Here's a video of one of the e90post moderator's cars, who also got the wavetrac. Shows one wheel in the air traction.
http://www.youtube.com/watch?v=Tudbb1JRVRQ


And here's a video from Wavetrac about the diff.
http://www.youtube.com/watch?v=WluaaGy0HwA


It's supposed to solve the main problem with the Quaife, which is that it stops working if one wheel is *completely* unloaded.

-scheherazade
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