[marconi118]

Is the OEM E92 M3 LSD mere like a Quaife or a Wavetrac ?

If possible to mount an OEM M3 diff would you go that route?
Will it be as good as wavetrac???

[ar design]

I have a Wavetrac, but have yet to test drive it... *sigh*

[stressdoc]

Originally Posted by marconi118

Is the OEM E92 M3 LSD mere like a Quaife or a Wavetrac ?

If possible to mount an OEM M3 diff would you go that route?
Will it be as good as wavetrac???

Possible to mount M3 diff, but difficult, need to modify driveshafts. Software also an unknown. Not a viable option.

IMO the single most important issue in regard to LSD is getting a real expert to do the work. In Euro: Birds or Drexler; in USA: Koala, HPA, a few others.

[ar design]

Originally Posted by stressdoc

Possible to mount M3 diff, but difficult, need to modify driveshafts. Software also an unknown. Not a viable option.

IMO the single most important issue in regard to LSD is getting a real expert to do the work. In Euro: Birds or Drexler; in USA: Koala, HPA, a few others.

HPA/Diffs Online did ours!

[marconi118]

Originally Posted by stressdoc

Possible to mount M3 diff, but difficult, need to modify driveshafts. Software also an unknown. Not a viable option.

IMO the single most important issue in regard to LSD is getting a real expert to do the work. In Euro: Birds or Drexler; in USA: Koala, HPA, a few others.

Actually I am doing this: a complete M3 subframe, need to adapt the shaft between gearbox and LSD

But want to know if the M3 is at least as good as Quaife or Wawetrac ?????

[Alpina_B3_Lux]

Originally Posted by marconi118

Is the OEM E92 M3 LSD mere like a Quaife or a Wavetrac ?

The OEM is a Drexler LSD. It has clutches, so you will have to do some maintenance on it at some point, unless the Quaife which (except maybe a fluid change) does not need this.

From what I've read from the dude in South Africa who mounted the M3 diff and had a Quaife previously, the M3 might be better under certain circumstances. I doubt however that unless you're a race or rallye driver you'll ever notice a significant difference as far as performance is concerned.

Alpina_B3_Lux

[marconi118]

Originally Posted by Alpina_B3_Lux

The OEM is a Drexler LSD. It has clutches, so you will have to do some maintenance on it at some point, unless the Quaife which (except maybe a fluid change) does not need this.

From what I've read from the dude in South Africa who mounted the M3 diff and had a Quaife previously, the M3 might be better under certain circumstances. I doubt however that unless you're a race or rallye driver you'll ever notice a significant difference as far as performance is concerned.

Alpina_B3_Lux

Thanks Marcel for this useful info! So now I can work on this mod with serenity.
Yes I did started this project reading the dude in South Africa thread (still waiting some mere pictures from him...)

Actually I have received the complete M3 subframe for 1600€ (including suspension, brakes and drive shaft), will be a direct bolt on except I need to make an adapter plate to match the M3 shaft to the 335I 6MT gearbox

Will open a thread in spring with a lot of pictures... now it is too cold to work on the car -10°C

[dlbrooks18]

Originally Posted by marconi118

Thanks Marcel for this useful info! So now I can work on this mod with serenity.
Yes I did started this project reading the dude in South Africa thread (still waiting some mere pictures from him...)

Actually I have received the complete M3 subframe for 1600€ (including suspension, brakes and drive shaft), will be a direct bolt on except I need to make an adapter plate to match the M3 shaft to the 335I 6MT gearbox

Will open a thread in spring with a lot of pictures... now it is too cold to work on the car -10°C

exciting project, can't wait to hear progress and ultimately how it performs

[Mr. 5]

Originally Posted by marconi118

Will open a thread in spring with a lot of pictures... now it is too cold to work on the car -10°C

I wouldn't know what to do with myself.
I was doing some work on the car last night in the garage with the garage door open at 8 pm. It was 65 F.

[scheherazade]

Originally Posted by Alpina_B3_Lux

The OEM is a Drexler LSD. It has clutches, so you will have to do some maintenance on it at some point, unless the Quaife which (except maybe a fluid change) does not need this.

From what I've read from the dude in South Africa who mounted the M3 diff and had a Quaife previously, the M3 might be better under certain circumstances. I doubt however that unless you're a race or rallye driver you'll ever notice a significant difference as far as performance is concerned.

Alpina_B3_Lux

Really? I thought it had the GKN-V

Presuming the M Z4 has the same LSD as the M 3.
http://www.zpost.com/forums/showthread.php?t=287976

Notice it says right on it : http://i8.photobucket.com/albums/a39...in88/diff3.jpg

GKN web site :
http://www.gkndriveline.com/drivelin...visco-lok.html

You can visually compare that to the M3 and see they're the same thing here :
http://www.bmw.com/com/en/newvehicle...tial_lock.html

The GKN is a viscous locking differential.

About GKN LSD type : http://en.wikipedia.org/wiki/Limited...ential#Viscous

The M3's GKN LSD is different from the Drexler LSD.








Drexler and OS Giken (and Hartge for that matter) work the same way.

The Drexler is an input-torque actuated LSD, like the OS Giken.
Merely accelerating or decelerating the wheels relative to their current rotating speed will cause a locking effect.
Whey you see '1' way : only locks on acceleration
When you see '1.x' way : locks '1' on acceleration, and "x/10 of 1" on deceleration.
When you see '2' way : locks the same amount on acceleration and on deceleration.

Diagrams of how it works : http://www.tomei-p.co.jp/_2003web-ca...ct-feature.htm

Notice the Drexler arrangement :
http://www.drexler-drivetrain.com/th..._Drawing_9.jpg
http://www.drexler-drivetrain.com/th...Drawing_12.jpg

Notice the OS Giken arrangement :
http://www.unitrax.biz/wp-content/up...te-c6-lsd2.jpg
http://image.turbomagazine.com/f/149..._giken_lsd.jpg

About Drexler / OS Giken LSD type : http://en.wikipedia.org/wiki/Limited...lutch_Type_LSD









The Quaife / Wavetrac is yet another kind of LSD.

About Quaife / Wavetrac LSD Type http://en.wikipedia.org/wiki/Limited...ial#Geared_LSD

Cutaway :
http://www.regal-shop.co.uk/acatalog/F23.jpg

This works by simply transferring power between wheels via a set of helical cut gears. Because the gears are not cut straight, they want to 'push out to the side' when there is a load on them. This pushes them into the differential body, and they make friction. It's essentially locking the wheels together so they spin at a similar rate, but to have any locking force to one another, both wheels need some load (otherwise the only locking force between wheels is plain friction from inefficiency)

The wavetrac is a slight modification, which adds a center friction plate.
It's attached to a 'wavy' surface, which pushes the plate to the center and the left/right sides rub.

That way there's an 'extra friction producer' that doesn't need wheel-load to work.

http://www.autotechdriveline.com/ima...6-0720074b.jpg
http://www.autotechdriveline.com/a_wavdiff.shtml






Generally:

(Note, when I say 'next stage' : I mean "better for specialized driving, can be worse/intrusive for daily driving")

Viscous LSD is a 'basic' LSD. It's typically the kind of LSD that cars start with and you upgrade from. Check out the viper forums of you need proof...
uses oil to press friction plates together. (like the M3's - i think)
uses a kind of fluid that turns solid when perturbed. Relative spin makes the fluid inside the diff go solid, and locks the mechanism together.
It's hard to describe because it has a bit of 'how you look at it', and designs vary.
This is an "after the fact" LSD.


The next stage is Torsen/Quaife/Wavetrac. They are nice because they are non-intrusive, and they work in a gradual manner (smooth locking effect). They essentially lock only as much as they need to in regards to wheel load. The greater the difference in wheel load, the more they lock. However, once you break loose, the locking effect greatly diminishes. Balanced wheel spin is not guaranteed.
This is a "pro active" LSD.


The next stage is a clutch type.
There are many kinds, but the two major paths are :
(Input torque actuated)
(Wheel spin actuated)

Wheel spin actuated LSDs are essentially open, until a wheel starts to spin out. This causes a center section to spin and spread a set of actuators, which move friction plates so they touch and resist.
These are nice because they only work when needed, but they come on suddenly and shockingly.
This is an "after the fact" LSD.

Input torque actuated lock first, then spin . The early locking effect is what makes them useful in resisting oversteer. The inside wheel 'pushes', preventing the tail from going out. Once both wheels spin out, the differential keeps both spinning at a balanced speed, making it extremely easy to power steer. However, the 'extra light-throttle understeer' is of no help to AWD folks, which have a hard time with understeer as it is. RWD folks can set their suspension to oversteer like crazy, and then use the LSD + their throttle to modulate how much and when.
This is a "pro active" LSD.


The next stage (if you off-road) would be an eaton locker.
This is mostly good for off-roading, as it's heavily 'on' and 'off' in action. When it's 'on', it's 100%. When it's off... it's off.
This is an "after the fact" LSD.


The next stage (ONLY if you drag race, or certain off-road if you don't have a selectable locker), is a drag spool.
This is essentially a solid differential. Both wheels always spin exactly the same speed.
This is a "pro active" LSD.








If I had to play favorites :
(i.e. personally, what I'd get if I was choosing from each type)

viscous :
better than open...

torque sensing :
wavetrac
(just because it tries to solve the limitations innate to all torsen lsds.)

clutch :
os giken
(so many wet clutches that it's hard to wear it out. There are other similar models with lots of clutches, though. it's not as unique in its genre as the wavetrac is in its genre.)


But ultimately, they're all better than open. Unless you take things to the extreme, any upgrade path is going to give you all the gains you are looking for.


I currently use the wavetrac, and I'm happy with it.
(If my car was RWD, I would have gotten the OS Giken)


-scheherazade







p.s.
Pics of OS Giken awesomeness :
600 hp race car : http://www.0-60mag.com/online/?p=2524
900 hp race car : http://speedhunters.com/archive/2009...maranello.aspx

[marconi118]

So finally how performs the M3 GKN style LSD compared to Drexeler, Quaife and Wavetrac ??

Will the M3 one lock if one tire has completely lost adherence (lift off)

[scheherazade]

Originally Posted by marconi118

So finally how performs the M3 GKN style LSD compared to Drexeler, Quaife and Wavetrac ??

Will the M3 one lock if one tire has completely lost adherence (lift off)

It depends what you want. There is no 'better or worse' in the absolute sense.

GKN lock will increase after you have wheel spin.

Quaife lock will relax after you have wheel spin.

Quaife will lock before you have wheel spin, to prevent wheel spin from happening.

Drexler will lock before you have wheel spin, to prevent wheel spin from happening.

GKN will not lock pre-emptively, and will not help prevent wheel spin - it only deals with it after it happens.

GKN and Quaife do not lock 100%, they merely resist free-spinning.

Drexler-type LSDs can generally lock harder, having a more balanced wheel spin.
The OS Giken can lock 100%.

Drexler-type LSDs will 'push through the inside while turning and accelerating' as lock onsets, causing understeer.

(Which is why it's less DD than the others. You have to use your throttle to manage under/over steer. You can actually romp the gas when making a turn and launch yourself straight forward, instead of turning. Throttle management is required - so a more competent driver is required)

Quaife will remain mostly neutral as lock onsets, not interfering much with steering.

GKN, since it won't lock before wheel spin [see next point], also will not interfere with steering.

GKN will *ever so slightly* lock on turns - because of the increased relative wheel spin. You won't notice it unless you're 'at the limits', or doing lots of turning like in auto-x.

Drexler will balance wheel spin after both wheels break loose, making it extremely easy to handle the car.

Quaife and GKN will not balance wheel spin after both wheels break loose, making the car yaw rate less deterministic.

Quaife will 'relax' if you take your foot off the gas.
(Engine braking should also put some load on the helical gears)

GVN will remain somewhat locked for a moment after you take your foot of the gas

Drexler / OS Giken depending on the setup can be made to lock on deceleration. Would remain neutral if you throttle match to your speed.

(You have to watch for sudden throttle lifts in a turn. Light throttle lift can cause understeer. Sudden heavy throttle lift can break you loose, and you suddenly oversteer - again requiring a more competent driver, and less DD friendly. A good driver can use these things as tools to help the car do what he wants. A poor driver will have an easier time getting into trouble. )






Pick your poison.

The entire list answers your first question. You have to choose what kind of behavior you want, to know what's "best for you".

I highlighted the answer to your second question.

-scheherazade

[marconi118]

Thanks a lot scheherazade for all this useful and educating infos

Indeed on the forum it is mostly talking about Quaife and Wavetrac...

My need is for DD and occasionally track and to be fast on the snow...

So I think the OEM M3 route is quite good, and suitable for a normal driver like me

[scheherazade]

Originally Posted by marconi118

My need is for DD and occasionally track and to be fast on the snow...

You may want to consider just the cheapest option.

If you do a lot of snow where you are spinning wheels on purpose (like pushing through thick snow), a 1.0 way locker would do you well.

-scheherazade

[marcel b]

Thanks scheherazade! absolutely the best information / comparison of LSD I have seen till now
Am doubting between Quaife, Wavetrac and Drexler...

[scheherazade]

Originally Posted by marcel b

Am doubting between Quaife, Wavetrac and Drexler...

Your list is in a good order.
The more extreme you intend to drive, the more you want something on the right side of your list.

Quaife will always be ok.

Wavetrac will be like the quaife.
It will help you drift/powersteer better, but if you don't do that sort of thing, it's of no use to you.

Drexler / OS Giken will give you tools/options with which to improve your cars handling and acceleration. But you can't turn it off.
If you use an aggressive setup (i.e. 2.0 locker @ 100%), hard driving can make you mentally tired.

-scheherazade

[scheherazade]

Originally Posted by Mr. 5

I wouldn't know what to do with myself.
I was doing some work on the car last night in the garage with the garage door open at 8 pm. It was 65 F.

Was ~20f with windchill last few days over here...

And people wonder why I didn't change my exhaust...

-scheherazade

[marcel b]

Originally Posted by scheherazade

Your list is in a good order.
The more extreme you intend to drive, the more you want something on the right side of your list.

Quaife will always be ok.

Wavetrac will be like the quaife.
It will help you drift/powersteer better, but if you don't do that sort of thing, it's of no use to you.

Drexler / OS Giken will give you tools/options with which to improve your cars handling and acceleration. But you can't turn it off.
If you use an aggressive setup (i.e. 2.0 locker @ 100%), hard driving can make you mentally tired.

-scheherazade

After reading your information, the Drexler seems to be a bit to "extreme" for me. (although I heard to customize it according to your needs)
Wavetrac seems still not to offer anything for a DCT, which is a bit strange to me, as the process with the welded gearring also works with the DCT (quaife is offering it) and for the rest I cannot imagine there is any difference between a LSD for a auto or a DCT....? or am I missing something here.
Because of it's functionality I am leaning to the wavetrac.

[e.n335]

^ do you know who could install a Quaife in Switzerland ?

[marcel b]

Collaction is official dealer in Switzerland. If you have a welded diff you maybe get a good offer there. (me however the made an offer above 5000 CHF....)
I will also ask my BMW dealer, or do you think they cannot / will not do it?

[e.n335]

Originally Posted by marcel b

Collaction is official dealer in Switzerland. If you have a welded diff you maybe get a good offer there. (me however the made an offer above 5000 CHF....)
I will also ask my BMW dealer, or do you think they cannot / will not do it?

Daehler is below CHF 5000 including hardware. However, I do have a bolted ring gear and so I need the diff only. Not sure whether the BMW dealer is willing to / capable to install it. I'll ask ZF / Duebendorf whether they are willing to install ...

IMO your most cost-effective scenario would be a Quaife or Wavetrac and a ring-gear from diffsonline.

[marcel b]

Originally Posted by e.n335

Daehler is below CHF 5000 including hardware. However, I do have a bolted ring gear and so I need the diff only. Not sure whether the BMW dealer is willing to / capable to install it. I'll ask ZF / Duebendorf whether they are willing to install ...

IMO your most cost-effective scenario would be a Quaife or Wavetrac and a ring-gear from diffsonline.

Birds offers the solution of me sending me final gear to them, and install the Quaife on my gearring. Only issue is that my car has to be stored for a week or so.
I checked diffsonline, couldn't really find what I would need.

A BMW dealer should be able to dismount the final drive and mount it back in again, I guess... (Birds in this case would do the complex work) taking the ring gear from the finaldrive (in your case) is already a bit more complicated. keep me posted!