[HP Autosport]

Originally Posted by neo871

Geared torque-sensitive differential
Audi Quattro Torsen Diff

Geared, torque-sensitive mechanical limited slip differentials utilize worm gears to "sense" torque on one shaft. The most famous versions are:

* Torsen differential invented by Vernon Gleasman in 1958, then sold to Gleason Corporation, who started marketing it in 1982;
* Quaife differential, sold under the name Automatic Torque Biasing Differential (ATB), covered by European Patent No. 130806A2.
* Eaton Corporation differential, sold under the name Eaton Detroit Truetrac.

Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g., one driven wheel lifts off the ground; or a summer tire comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive differential behaves like an open differential.

Geared LSDs are dependent on the torque and not on the speed difference between the output shafts. Such differentials may not be adequate on extremely slippery surfaces such as ice (or thin air, when a drive wheel loses ground contact altogether).[3]

Geared LSDs may be used:

* to reduce torque steer in front-wheel drive vehicles;
* as a center differential in four-wheel drive (e.g., on the Audi Quattro);
* in rear-wheel drive vehicles, to maximize traction and make oversteer easier to manage (as in drifting). Although, for extreme drifting, a geared LSD is less effective compared to a clutch type LSD.


i found this here: http://en.wikipedia.org/wiki/Limited_slip_differential but i don't understand the bolded part....could anyone explain why this would happen to Quaife LSD if this is what most people say about it:

the QUAIFE Differential powers both drive wheels under nearly all conditions, instead of just one.

With an ordinary open differential, standard on most cars, a lot of precious power is wasted during wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip, along the path of least resistance.

The QUAIFE, however, does just the opposite. It senses which wheel has better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. In cornering, while accelerating out of a turn, the QUAIFE biases greater power to the outside wheel, reducing inside-wheel spin. This allows the driver to begin accelerating earlier, exiting the corner at a higher speed

Nice find!

[Finnie]

I can't justify selling the 335i to buy an M3 so I've 99% decided to go for a quaife.

Emailed Birds about it before but can anyone suggest anyone remotely North who could install this for me. A 1200 mile round trip cannot be really justified!

[RagingKileak]

Speed Religion.

Matt

[spirocheter]

Anyone read this?

http://www.evo.co.uk/carreviews/evoc...w_3series.html

Quaiffe most definitely top priority mod IMO (after remap, which I couldn't resist for the money)

[HP Autosport]

Quaife LSD should be on everyone's mod list!

[Finnie]

i bought one and......because my specified garage didn't read the instructions I sent them before they agred to do it decided when I turned up that it would take about 10hours labour to fit it. I tild them to shove it and since I was thinking about selling the car early next year i sent the diff back to Birds in it's packaging without a fingerprint for a 20% re-stocking fee! Peed off doesn't describe it!

[SoYank]

Shame. You could have taken those ten hours and driven to Birds where they'd have you in and out of the shop in less than three hours without a restocking fee. If you call ahead to Birds they'd have a whole diff sitting there waiting for you to arrive and they wouldn't be spending the extra time opening the case and changing the insides.

[645Nm]

Thanks again for a brilliant review. This is a definite, absolutely REQUIRED mod for my car!

Thanks man...

And for visiting the Africa forum...

[spirocheter]

Anyone aware there is 'another company' who are currently developing a differential which may be significantly cheaper than the Quaiffe through Birds? I'd probably better not say who though!!

[E92Fan]

Originally Posted by spirocheter

Anyone aware there is 'another company' who are currently developing a differential which may be significantly cheaper than the Quaiffe through Birds? I'd probably better not say who though!!

Yes, there is something called a Wavetrac. Not quite the same as a Quaife - very similar in most respects, but uses two small clutch plates as well. Effectively supposed to provide up to a 100% locking effect.

There may be issues with it though, probably not in the way it works, but perhaps in its 'fitment'. We have yet to see - I believe Evolve are currently researching the possibilities of this Wavetrac differential.

The issue is that BMW have used different sized differentials for each model of vehicle, with some models using more than one size, depending on build number and date. It's very confusing, hence why there are I believe at least three separate Quaife differentials, in different sizes, for the current 3 series alone. Also that doesn't take into consideration the differences between welded and bolted differentials - I don't know how Wavetrac have got round the size issue, as I believe the Wavetrac is based on a Quaife 10N, which I think I'm right in saying doesn't fit a current 3 series. Further more, I don't know how Wavetrac have solved the issue of the welded crown wheel.

Judging by the experiences of machining the current Quaife differentials for application on vehicles with a welded diff, the machining process has to be extremely exact otherwise there will be an inaccuracy in the plane of the crown wheel, which if unnoticed or left unchecked will lead to vibration through the drive line and associated problems thereafter.

I am curious to see how successful the Wavetrac might be. So far, the Quaife has proved itself reliable, and provided the installers are competent, extremely easy to install in terms of accuracy of fitment and suitability to the application. That, the extensive knowledge and backup of Quaife, combined with the technical workshop at Birds and the confidence I have in their workmanship and engineering skills, will still put me firmly in the Quaife camp, despite the extra cost (which for a bolted differential may not be that much more... circa £900 for a bolted diff)

[TheMadDutchman]

Originally Posted by HP Autowerks

Quaife LSD should be on everyone's mod list!

Ditto!! Best solution out there IMO. Cooler differential fluid temperatures than a clutch type diff as well as no clutch discs to wear.

[spirocheter]

Originally Posted by E92Fan

Yes, there is something called a Wavetrac. Not quite the same as a Quaife - very similar in most respects, but uses two small clutch plates as well. Effectively supposed to provide up to a 100% locking effect.

There may be issues with it though, probably not in the way it works, but perhaps in its 'fitment'. We have yet to see - I believe Evolve are currently researching the possibilities of this Wavetrac differential.

The issue is that BMW have used different sized differentials for each model of vehicle, with some models using more than one size, depending on build number and date. It's very confusing, hence why there are I believe at least three separate Quaife differentials, in different sizes, for the current 3 series alone. Also that doesn't take into consideration the differences between welded and bolted differentials - I don't know how Wavetrac have got round the size issue, as I believe the Wavetrac is based on a Quaife 10N, which I think I'm right in saying doesn't fit a current 3 series. Further more, I don't know how Wavetrac have solved the issue of the welded crown wheel.

Judging by the experiences of machining the current Quaife differentials for application on vehicles with a welded diff, the machining process has to be extremely exact otherwise there will be an inaccuracy in the plane of the crown wheel, which if unnoticed or left unchecked will lead to vibration through the drive line and associated problems thereafter.

I am curious to see how successful the Wavetrac might be. So far, the Quaife has proved itself reliable, and provided the installers are competent, extremely easy to install in terms of accuracy of fitment and suitability to the application. That, the extensive knowledge and backup of Quaife, combined with the technical workshop at Birds and the confidence I have in their workmanship and engineering skills, will still put me firmly in the Quaife camp, despite the extra cost (which for a bolted differential may not be that much more... circa £900 for a bolted diff)

You knew already to whom I referred! You are very knowledgeable on this subject and it is with great interest I follow this thread. Certainly I agree Quaife is proven and a quality product. I would imagine Evolve would not go to market without a quality product though and what welcome competition this will bring! It seems from the interest in this thread there is a tremendous potential market for the LSD. I'm saving my pennies and may yet place one on order.

Any idea how the LSD will affect winter driving dynamics - ie on snow and ice. I would imagine it would serve to improve driveability ... any experiences?

[T335i]

Right, this looks like a mod I really need to do as well...

Does anyone know a good dealer in the netherlands, belgium or northeren france who has the experience of installing these diffs?
My e92 335i is from april 2007, anybody an idea if i have the bolted or welded diff?

thanks, T

[SoYank]

If you're planning to be in the Calais area then it's only about two hours, time of day dependent, to Buckinghamshire and Birds. Have a visit. Contrary to popular belief, the British aren't that bad a bunch of folks.

[dxb335d]

Whn was the change to welded ones? what production date?

and for what reason?

[SoYank]

Originally Posted by dxb335d

Whn was the change to welded ones? what production date?

and for what reason?

Maybe there's a bolt shortage.

[645Nm]

the more I read this thread...i must have this thing called LSD...it must be better under the car than under the skin or under the tongue...335 must have LSD...any sponsors...willing to sleep in and do the groceries...

[fastloop]

Originally Posted by T335i

My e92 335i is from april 2007, anybody an idea if i have the bolted or welded diff?

thanks, T

AFAIK, the change date was around 02/2007. Cars produced after this date will have the welded diff.

[RagingKileak]

Originally Posted by 335rocks

AFAIK, the change date was around 02/2007. Cars produced after this date will have the welded diff.

Erm, I think its actually between 02/07 and 05/07 - most people quote 03/07 as a good rough guide.

The only way to tell if your build date is around there - is to look.

Matt

[spirocheter]

I phoned Birds and they asked for several digits of my Chassis number despite the car being registered first in December 2007.. presume there are a few exceptions here and there, might be worth checking with them.

[RagingKileak]

Originally Posted by spirocheter

I phoned Birds and they asked for several digits of my Chassis number despite the car being registered first in December 2007.. presume there are a few exceptions here and there, might be worth checking with them.

Indeed.

Mine is 04/07 and Birds couldnt tell me from the chassis code - and thats all the info your getting from me about what I might or might not be up to!!

Matt

[spirocheter]

Originally Posted by RagingKileak

Indeed.

Mine is 04/07 and Birds couldnt tell me from the chassis code - and thats all the info your getting from me about what I might or might not be up to!!

Matt

Yeah yeah yeah.... (LOL, love the suspense).... sure you'll be buying a Quaiffe (could you please PM me and let me know how much they've agreed to).

Also, I would guess you're looking towards uprated ARBs and possibly braking upgrade... that or else a new coil over set up? Not trying to force your hand, though at least that's what I'd be planning if I had 3K plus to play with (with discount for several items I would hope I could get AP, Quaiffe and ARBs)...?

Looks forwards to reading the reviews....