Which Limited Slip Diff?
Discussion
Having recently acquired an Alpina D4 (used), I realise that I am in need of a limited slip diff. I have sent out emails to Birds (Quaife), Alpina Germany and UK and the Drexler importer for UK and am enquiring with BMW.
I'm thinking that the Birds option will be by far the best value. BMW and Alpina use Drexler I believe. Does anyone have any first hand experience of positives or negatives? I haven't heard of anyone (other than 1 person who sounded like they had an "axe to grind") who had any issues with Quaife so maybe I shouldn't overthink it and go for them?
Thanks for any help.
(And when I say its needs LSD, I've had quite a number of powerful rear drive cars and the D4 spins the rears up easier than anything I've had......but not in a useful way)
I'm thinking that the Birds option will be by far the best value. BMW and Alpina use Drexler I believe. Does anyone have any first hand experience of positives or negatives? I haven't heard of anyone (other than 1 person who sounded like they had an "axe to grind") who had any issues with Quaife so maybe I shouldn't overthink it and go for them?
Thanks for any help.
(And when I say its needs LSD, I've had quite a number of powerful rear drive cars and the D4 spins the rears up easier than anything I've had......but not in a useful way)
I'm in the same situation regarding my m135i.
M Performance diff is made by Drexler I believe and is a plate diff.
Quaife is an ATB diff.
Both will be good.
In my case the M performance diff comes as a whole unit so you can simply swap them out. Around £2200.
If you want a Quaife or any other ATB you either need an exchange unit or to pay just as much ... Birds quote around £2100 fitted with them keeping your existing diff.
for value I'd personally buy a replacement unit so I'd be looking at the m performance once really.
That’s interesting re the MPerf one being a plate based diff. I honestly thought that the Drexler was helical gears as with Quaife. If the BMW one is plates then I think i would rather Quaife anyway.
The plate based ones I would have thought need an electronic element to them in order to adjust the clutch type situation which seemed to me to be unlikely as an added aftermarket situation.
Drexler certainly advertise separately as being a gear based diff.
The plate based ones I would have thought need an electronic element to them in order to adjust the clutch type situation which seemed to me to be unlikely as an added aftermarket situation.
Drexler certainly advertise separately as being a gear based diff.
I just retro-fitted a BMW M Performance LSD to my 2016 M235i fitted by my BMW garage. I have the original diff and the mechanics advised trying to sell it on eBay. Apparently it's not unusual for a garages to source a 2nd. hand diff at a discount to a customer when one needs replacing, especially if the car has some mileage on it.
Definitely an improvement in straight-line hard acceleration and much more predictable on powering-out of corners. And on Alpine hairpins it was a huge improvement. I don't track, but I'd say it's worth retro-fitting an LSD if you have a performance model. The M1xxi and M2xxi should really have it as standard, given they're 330hp or so RWD.
Definitely an improvement in straight-line hard acceleration and much more predictable on powering-out of corners. And on Alpine hairpins it was a huge improvement. I don't track, but I'd say it's worth retro-fitting an LSD if you have a performance model. The M1xxi and M2xxi should really have it as standard, given they're 330hp or so RWD.
Edited by msej449 on Monday 27th August 09:03
Re “huh”? The LSD on cars from the factory which have plate (clutch) based systems from what I can gather have essentially an electronically actuated clutch plate at the diff which locks at a variable nature based on the clutch plates slipping to a greater or lesser extent. This is why the plate based lsd’s need maintenance. Ironically when you order an aftermarket LSD even from BMW, they use a “Drexler” mechanical gear based LSD that works purely on the mechanical nature of one wheel spinning faster than the other on the axle.
So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
I’m very happy to have someone with genuine knowledge tell me differently. I think its interesting that the factory BMW LSD on cars like the M cars is different to the aftermarket ones and interesting that the mechanical diff is actually the purer and possibly more motorsport version.
Alpina cars from the factory if they have the LSD option ticked come with Drexler mechanical LSD’s.
:-)
So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
I’m very happy to have someone with genuine knowledge tell me differently. I think its interesting that the factory BMW LSD on cars like the M cars is different to the aftermarket ones and interesting that the mechanical diff is actually the purer and possibly more motorsport version.
Alpina cars from the factory if they have the LSD option ticked come with Drexler mechanical LSD’s.
:-)
Till135 said:
Re “huh”? The LSD on cars from the factory which have plate (clutch) based systems from what I can gather have essentially an electronically actuated clutch plate at the diff which locks at a variable nature based on the clutch plates slipping to a greater or lesser extent. This is why the plate based lsd’s need maintenance. Ironically when you order an aftermarket LSD even from BMW, they use a “Drexler” mechanical gear based LSD that works purely on the mechanical nature of one wheel spinning faster than the other on the axle.
So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
ALL clutch pack LSD's need maintenance because of the clutch packs (nothing to do with any electronics) and this includes aftermarket ones. None of the aftermarket clutch pack LSD's need any sort of additional electronic control.So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
The gear type torque biasing diff's like the Quaife and the Wavetrac are maintenance free, although they also don't work in the same way as a clutch plate diff, and this needs to be understood when driving.
I've had both, and can recommend both, but again, that was on the basis of different strokes for different folks.
Gear type is better for a purely road car use, clutch pack better for track and off-road.....IMHO.
Till135 said:
Re “huh”? The LSD on cars from the factory which have plate (clutch) based systems from what I can gather have essentially an electronically actuated clutch plate at the diff which locks at a variable nature based on the clutch plates slipping to a greater or lesser extent. This is why the plate based lsd’s need maintenance. Ironically when you order an aftermarket LSD even from BMW, they use a “Drexler” mechanical gear based LSD that works purely on the mechanical nature of one wheel spinning faster than the other on the axle.
So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
I’m very happy to have someone with genuine knowledge tell me differently. I think its interesting that the factory BMW LSD on cars like the M cars is different to the aftermarket ones and interesting that the mechanical diff is actually the purer and possibly more motorsport version.
Alpina cars from the factory if they have the LSD option ticked come with Drexler mechanical LSD’s.
:-)
Wrong.So the aftermarket mechanical LSD is maintenance free and relies purely on mechanics. The clutch system needs electronic measurement across the axle which will then activate/deactivate the “clutch plates”.
I’m very happy to have someone with genuine knowledge tell me differently. I think its interesting that the factory BMW LSD on cars like the M cars is different to the aftermarket ones and interesting that the mechanical diff is actually the purer and possibly more motorsport version.
Alpina cars from the factory if they have the LSD option ticked come with Drexler mechanical LSD’s.
:-)
You do not need electronics in a mechanical plated limited slip diff.
Some LSD's are variable (Eg some high end diffs on Ferrari's etc and some higher performance cars a little further down the food chain).
These may be called E-LSD or variable LSD etc. IE Electronic limited slip diff.
These use electronics to continuously control the amount of lock (IE between fully open and fully shut)
In much the same way that Haldex operates on many VAG vehicles.
On my particular BMW (f21 m135i) the M-Performance diff is a mechanical plate diff. It has 3 clutch discs inside and through ramp angle setup etc it provides 30% lock under acceleration and around 9% lock on deceleration. It is mechanical, not electrical.
I've done some research and it doesn't say 100%, but on the D4 the states :
"The hardware itself consists of a torque-sensing differential of motor sports quality developed in cooperation with the company Drexler. It is assembled by hand with precision-forged gear wheels and a CNC-milled housing"
This makes me think that that it is an ATB (torque biasing) diff more in like with a Quaife which uses gears to multiply torque eg 2.5:1 .
The "downside" is that when one wheel is unloaded (ie in the air) then 2.5 x 0 is still 0.
That being said the implications of this are minimal on the road.
The ATB diffs are fit and forget and need nothing other than oil changes.
The locking action can be unpredictable due to what I mentioned above
Certainly a plate diff is generally more predictable and preferred for track use.
Rebuilds are not horrifically expensive, but are needed occasionally, but on a road car that has limited to no track use is basically fit and forget
and can be customised to your own personal needs when it is rebuilt.
xjay1337 said:
Wrong.
You do not need electronics in a mechanical plated limited slip diff.
Some LSD's are variable (Eg some high end diffs on Ferrari's etc and some higher performance cars a little further down the food chain).
These may be called E-LSD or variable LSD etc. IE Electronic limited slip diff.
These use electronics to continuously control the amount of lock (IE between fully open and fully shut)
In much the same way that Haldex operates on many VAG vehicles.
On my particular BMW (f21 m135i) the M-Performance diff is a mechanical plate diff. It has 3 clutch discs inside and through ramp angle setup etc it provides 30% lock under acceleration and around 9% lock on deceleration. It is mechanical, not electrical.
I've done some research and it doesn't say 100%, but on the D4 the states :
"The hardware itself consists of a torque-sensing differential of motor sports quality developed in cooperation with the company Drexler. It is assembled by hand with precision-forged gear wheels and a CNC-milled housing"
This makes me think that that it is an ATB (torque biasing) diff more in like with a Quaife which uses gears to multiply torque eg 2.5:1 .
The "downside" is that when one wheel is unloaded (ie in the air) then 2.5 x 0 is still 0.
That being said the implications of this are minimal on the road.
The ATB diffs are fit and forget and need nothing other than oil changes.
The locking action can be unpredictable due to what I mentioned above
Certainly a plate diff is generally more predictable and preferred for track use.
Rebuilds are not horrifically expensive, but are needed occasionally, but on a road car that has limited to no track use is basically fit and forget
and can be customised to your own personal needs when it is rebuilt.
Great response thanks. Interestingly then today I had another response from Alpina, Germany. They have advised the Drexler Diff through Sytner but also that they will then upload a new piece of code to allow the DSC to work with the LSD. You do not need electronics in a mechanical plated limited slip diff.
Some LSD's are variable (Eg some high end diffs on Ferrari's etc and some higher performance cars a little further down the food chain).
These may be called E-LSD or variable LSD etc. IE Electronic limited slip diff.
These use electronics to continuously control the amount of lock (IE between fully open and fully shut)
In much the same way that Haldex operates on many VAG vehicles.
On my particular BMW (f21 m135i) the M-Performance diff is a mechanical plate diff. It has 3 clutch discs inside and through ramp angle setup etc it provides 30% lock under acceleration and around 9% lock on deceleration. It is mechanical, not electrical.
I've done some research and it doesn't say 100%, but on the D4 the states :
"The hardware itself consists of a torque-sensing differential of motor sports quality developed in cooperation with the company Drexler. It is assembled by hand with precision-forged gear wheels and a CNC-milled housing"
This makes me think that that it is an ATB (torque biasing) diff more in like with a Quaife which uses gears to multiply torque eg 2.5:1 .
The "downside" is that when one wheel is unloaded (ie in the air) then 2.5 x 0 is still 0.
That being said the implications of this are minimal on the road.
The ATB diffs are fit and forget and need nothing other than oil changes.
The locking action can be unpredictable due to what I mentioned above
Certainly a plate diff is generally more predictable and preferred for track use.
Rebuilds are not horrifically expensive, but are needed occasionally, but on a road car that has limited to no track use is basically fit and forget
and can be customised to your own personal needs when it is rebuilt.
I think that’s the full on approach and basically gives me what Alpina would do in the factory as part of a new car order.
Till135 said:
Interestingly then today I had another response from Alpina, Germany. They have advised the Drexler Diff through Sytner but also that they will then upload a new piece of code to allow the DSC to work with the LSD.
Might be coding the first press of DSC/DTC to be default once diff is fitted....or at least 'softening' its actions.Till135 said:
I think that’s the full on approach and basically gives me what Alpina would do in the factory as part of a new car order.
Indeed.Love what Alpina do.
Till135 said:
Great response thanks. Interestingly then today I had another response from Alpina, Germany. They have advised the Drexler Diff through Sytner but also that they will then upload a new piece of code to allow the DSC to work with the LSD.
I think that’s the full on approach and basically gives me what Alpina would do in the factory as part of a new car order.
The DSC will work fine without any coding changes.I think that’s the full on approach and basically gives me what Alpina would do in the factory as part of a new car order.
Fitted a Quaife diff to my 135i back in June, very nice and starting to enjoy it more.
My Michelin PSS have worn out quicker with it fitted so will be fitting 255/35/18 PS4 in due course. Grip is more predictable even with shot rear tyres.
Might still upgrade to an M / AMG next year. Feeling is I’d put a Quaife in them too.
Would happily do business with Birds again.
My Michelin PSS have worn out quicker with it fitted so will be fitting 255/35/18 PS4 in due course. Grip is more predictable even with shot rear tyres.
Might still upgrade to an M / AMG next year. Feeling is I’d put a Quaife in them too.
Would happily do business with Birds again.
Gassing Station | BMW General | Top of Page | What's New | My Stuff