Big LSD Shootout... OS Giken, Drexler, Titan, GKN, ZF...

[2K11SGCoupe]

Hello Driftflo,

Thank you for sharing your vast BMW differential experience with the forum. I have enjoyed reading your post and viewing the images of differential guts.

I am writing to inquire about ATBs. I am less interested in tracking/drifting my car and when my OEM lsd is toast I would like to upgrade to an ATB style unit which will perform consistently and longer than a clutch style LSD before requiring service.

Throughout your post you have stated that an ATB does not suit your needs. Primarily this seems to be because it behaves like an open differential while decelerating or upon lifting the gas. I can appreciate your racing requirements and respect that you want a different level of performance than me or most drivers who primarily operate their M3 as a street car and attend track events on occasion.

I have operated Quaife units in my 1976 turbocharged 2002 and 325 touring for many years and found the Quaife to offer a tremendous improvement in rear axle feel while accelerating and powering through curves.

You definitely have a lot of experience and I would like to request your opinion. What do you think is the best performing ATB on the market?

You mentioned the Torsen, Wavetrac and Quaife offering a slight upgrade in performance to the stock LSD. Of the non-clutch style ATB units available for the e92 M3, which would you recommend?

Because of my positive past experience with Quaife I was leaning that direction for my M3 but would like to know which ATB unit you feel offers the best performance and value.

Thanks in advance for any insight which can share.

Kurt

[driftflo]

hey kurt,

if one of my customers wants an ATB i normally use wavetrac and so far there were no complains about them.
for myself, i have not had the time to really try and compare the different atb units against each other so far. there is so much research to do and i have so much more ideas on lsd setups that i guess this will not change in the next time. although i would definitely like to do some own testing on atb units in the future too!

[kevinlevrone]

I received my rebuilt Drexler LSD today and installed it. This time I asked them to set it up with 40/50 ramp angles (as driftflo recommended) instead of my former 50/40 setup. So more lock (about 50%) under acceleration and less (about 40%) on deceleration. I must say I am impressed and I love the setup. Great amounts of grip for the cold weather and my worn Michelin A/S 3 tires. Car is not a lot more twitchy than before, but it does seem to be just a bit more tail happy on sudden acceleration, but it quickly gets back in line without any help from my side. And like my previous Drexler setup, no noises or other unpleasant behaviour from the LSD. It is dead silent.

[driftflo]

Originally Posted by kevinlevrone

I received my rebuilt Drexler LSD today and installed it. This time I asked them to set it up with 40/50 ramp angles (as driftflo recommended) instead of my former 50/40 setup. So more lock (about 50%) under acceleration and less (about 40%) on deceleration. I must say I am impressed and I love the setup. Great amounts of grip for the cold weather and my worn Michelin A/S 3 tires. Car is not a lot more twitchy than before, but it does seem to be just a bit more tail happy on sudden acceleration, but it quickly gets back in line without any help from my side. And like my previous Drexler setup, no noises or other unpleasant behaviour from the LSD. It is dead silent.

thanks for the feedback und great that my theory went in the right direction for you :-)

[kevinlevrone]

Originally Posted by driftflo

thanks for the feedback und great that my theory went in the right direction for you :-)

Thanks. It really does make a difference in traction but the nice thing is that I can now much more easily steer the car with some throttle input, which is great. I can "feel" the LSD action much better than before.

But after some more testing, I did notice some (minor) annoyance with the diff: when accelerating in a tight turn from very low speeds I feel some "stuttering" from the inside wheel. Naturally it wants to move at the same speed as the outer wheel as the LSD is engaged. I wonder if this will smooth out over time, or I will just have to live with it ? I wonder if this will smooth out if I do some 8-figures with the car in a parking lot, to break in the clutches a bit ?

[driftflo]

this behaviour is normal for a freshly built high locking lsd unit. when the clutches wear out over time this will get less but this behaviour is a sign for vital and fresh clutches. you can drive some 8-figures but i doubt that it will improve much. the clutches drexler uses do not need this bed-in process, i.e. the kaaz lsd units do need it necessarily.
if you can live with it leave it like it is. if you want to smooth it a little, put in some fm additive but keep in mind that this also compromises the lockup capability.

[8k3]

Originally Posted by kevinlevrone

Thanks. It really does make a difference in traction but the nice thing is that I can now much more easily steer the car with some throttle input, which is great. I can "feel" the LSD action much better than before.

But after some more testing, I did notice some (minor) annoyance with the diff: when accelerating in a tight turn from very low speeds I feel some "stuttering" from the inside wheel. Naturally it wants to move at the same speed as the outer wheel as the LSD is engaged. I wonder if this will smooth out over time, or I will just have to live with it ? I wonder if this will smooth out if I do some 8-figures with the car in a parking lot, to break in the clutches a bit ?

Kevin Levrone, aka runner up Mr. Olympia? Lol, get back at it

[kevinlevrone]

Originally Posted by driftflo

this behaviour is normal for a freshly built high locking lsd unit. when the clutches wear out over time this will get less but this behaviour is a sign for vital and fresh clutches. you can drive some 8-figures but i doubt that it will improve much. the clutches drexler uses do not need this bed-in process, i.e. the kaaz lsd units do need it necessarily.
if you can live with it leave it like it is. if you want to smooth it a little, put in some fm additive but keep in mind that this also compromises the lockup capability.

Nevermind, it smoothed out significantly over the last days to the point that there is not an issue anymore. I am still impressed with the traction and behaviour, makes me think that the first time I installed it 4 years ago the lockup percentage was just too low to have a significant impact in traction. Now the car is finally behaving as it should have been from the beginning, with lots of (unexpected on this weather) traction and easy throttle steering.

[audirmz]

Hello guys,

Since 4 months i installed the new differential that has been built from Florian Seibold (limitidedslip.de) driftflo username.

My previous car was an e36 m3 evo 321ps which i enjoyed until the last day i sold it. As already known it has a ZF lsd plated diff with 25% lock and indeed it was very fun to drive.
Then i bought my e46 m3 and generally the car was in a higher level except the rear diff which it did the job but not so precise and plant.
So after many days and hours spended in forums i had the luck to find the website from Florian from this LSD SHOOTOUT POST
Although i know many things how an lsd works i took contact with him to ask what he would suggest me.
After writing many helpfull mails with him we decided to go with the following setup:

4 clutch upgrade with 45/45 degrees ramps in ZF 2way housing that would upgrade the locking precentage at 40-45%
Between 50-70nm static preload as i wanted as less as possible understeer and no noises or greedings
3.91 final drive
All bearings and seals new.

My requirements:
3-5 times per year in Nurburgring with semi slicks
1-2 times per month in mountain passes
2 drift events per year
and i wanted still to be used as a daily car when it needs.

I must admit that it was a diffucult decision because of many different opinions from this post and from many other forums.
This happens because the most people doesnt know how an lsd works and even less have personal experience and tried out many different setups so they can help us to decide what should we choose that will be the right one for our requirements.

Trust me all this guy has tones of personal experients
He has a E36 for drift school
A E46 M3 race car that tried out many setups
A E92 M3 private car for his joyness the same here if i remember right over 6 different brands and many from his own ZF setups
And a MERCEDES C63AMG Station for his family that recently upgraded the oem LSD as i read here.

All this i saw personally because i had the luck to pick up my diff from his house in Germany as i live in Switzerland and he is 280km far away from me.
I met him personally we spoke around 2 hours about diffs , i saw also his labor.
Really a good guy full of knowledges.

Now the result after 4 months driving the car in every condition.

All the thoughts that the car will be abruptness and maybe dangerous in the wet just dissapeared when i drove it.
Its just amazing how the car behaves so planted very smooth operation excellent control with the gas pedal during drifting not lock unlock like the oem and no waiting until it will lock, its just there silent and does really the job that everybody would wish.
Even in the wet its just so easy to control the car during the corners , the rear end gives me so much trust , it warns before it will slide. With few words 100% satisfied.

The final drive 3.91 was another big improvement its everywhere faster during accelaration. The average consumption rised 0.4l pro 100km and the rpm are a bit higher but nothing to disturb. I was between 4.10 and 3.91 and for a street car i suggest 3.91 its just fine but for the track and especially Nurburgring i would go with 4.10.
As for the trackdays with the semislicks the new lsd operates very decent , no understeer noiseless and a nice feeling when i hit the gas after a turn like it slightly opens the tail, like the wheel is in the rear
Its feels very stable during deceleration in comparison with the oem one especially in high speeds the rear is more tight. This happens because the oem one it locks only in acceleration but the new is 2way
No problems with the DSC control.

My conclusion is that it paids of the money for this upgrade and my opinion for a car that has street tyres on it and often goes for trackdays with semi slicks , this is all you need. No more locking no more preload and no need for hardcore aftermarket units.
The final drive has to do with the personal preferences that everybody has.

For track work and slicks i can not have an opinion but be sure that Florian has. But as he told me very clearly there is not a differential that can do everything but there is a setup that suits your skills, use and style of driving and i am very happy that i went with his suggestion.

This guy is only to reccomend, a really pro that knows perfect his stuff.

Thank you very much Florian and soon you will hear from me as my brother bought a BMW 130 unfortunately with open diff.

[driftflo]

after getting some inquiries about lsd units and all you need to fit them in a m3 case i took a pic of a complete conversion package consisting of:

- any clutch type or helical lsd unit like my own (pictured) or drexler, os giken, wavetrac, ...
- two side flanges (same length)
- two bearings with according races (or you can reuse the old ones if you can pull them off the oe lsd without destroying them)
- two flange seals (if you replace the bearings/races)




today i disassembled a "m235i racing" drexler lsd... nice stuff... i will take some pics of the rebuild... stay tuned...

[Bohn101]

DriftFlo,

I've got a 435i, planning on getting the M Performance LSD. Was the one you mentioned for the M235i the same unit? Did you ever get some pics? Probably won't see much track time, but will see plenty of empty canyon road bliss. Do you figure the 30/8 percentages for lockup are worth the investment? Do you actually make LSD's yourself? What kind of prices and are dealers willing to install them?

Cheers,

Originally Posted by driftflo

after getting some inquiries about lsd units and all you need to fit them in a m3 case i took a pic of a complete conversion package consisting of:

- any clutch type or helical lsd unit like my own (pictured) or drexler, os giken, wavetrac, ...
- two side flanges (same length)
- two bearings with according races (or you can reuse the old ones if you can pull them off the oe lsd without destroying them)
- two flange seals (if you replace the bearings/races)




today i disassembled a "m235i racing" drexler lsd... nice stuff... i will take some pics of the rebuild... stay tuned...

[driftflo]

sorry for the late reply. i am pretty busy these days. got some new grinding and turning machines that need to be set up.

i did not make any pics of the m235i racing lsd core as the customer was busy and waited while i rebuilt it. but the setup is just the same as in the m3 gt4 and in the early z4 gt3 cars. only the lsd case and caps are different to fit in the 215L pumpkin.

the 435i also has the 215L axle. the m performance lsd is quite ok. you will noticably feel the 30% lockup on power... you will most likely not feel any improvements under braking. but for a bmw FR car, the more important thing is the lockup on power. just throw it in and drive it for a while. if you feel to rebuild it in the future due to wear or because you just want to upgrade the unit you can put in another setup i.e. the gt4 one that locks noticably more on power and coast.

i try to make some pics of a M235i racing core when i have the next unit here for rebuild. or maybe i can even show you a new unit as i am about to order a bigger quantity of lsd cores and parts from drexler soon and maybe i will add such a core as well.


so far i only build some parts myself but i do not build complete lsd units from scratch. i use old zf lsd cores and rebuild them from scratch and i have some suppliers of lsd cores and parts (like drexler, titan, bacci, kaaz, ...) that i also modify and rebuild to my own specs or to special customer needs.

[///Mobbin]

Originally Posted by italyix

Finally US Customs released the package and this beauty showed up at my door steps Saturday.

Will be a while before I get it installed, and will post results when I do.

The unit is solid to say the least. Housing is machined and feels nice and sturdy.

Curious if you can share some details on thoughts on your setup?

[italyix]

Originally Posted by ///Mobbin

Curious if you can share some details on thoughts on your setup?

Finally got it installed and it all works. The car is very well composed and I can take turns much much faster. At parking lot speeds and tight turns, the diff locks and almost acts like a welded diff, must be the clutch packs still breaking in.

I have no track time yet, hopefully in November I will go but coming from a shot oem diff which was so bad that the shop had to break parts apart just to get the components out, I am really impressed by how a good diff works.

I forgot to add that mine is a 45/45 ramp rate 1.5 way. The best way I can describe it is the parachuting effect while turning is gone. You know what I mean when you experience it. Now the car effortlessly turns and pulls away from corners smoothly.

[BanjoPaterson]

First a disclaimer. I love that this thread exists and understand it about as much as advanced quantum mechanics... particularly after reading:

"...4 clutch upgrade with 45/45 degrees ramps in ZF 2way housing that would upgrade the locking precentage at 40-45%.."

However, if the LSD-nerds hang out here then this is the place to ask the questions bugging me. Because my car is leased, I can mod it/repair it/upgrade it on pre-tax dollars in preparation for buying it outright at the end of the lease. I've already done throttle actuators (replaced reduction gears with brass/delrin set); have a set of RBs in my garage awaiting March next year; and already replaced the DCT oil+pan+seals.

To my horror I saw a throw-away line that the LSD on the E9x M3 has a life expectancy of about 60-80K miles (!). A few people dismissed this, but on the turner sport website (https://www.turnermotorsport.com/p-3...=AQEBAQEB)they state:

"Limited Slip Options The M3's M Variable locking differential is genius when it's working properly. Unfortunately, as many M3 owners have come to find, the system only has a service life of 80,000 miles (sometimes less) and then the viscous unit inside starts to fail (is your's clunking?)."

Now - they probably have an agenda, somewhat, of wanting to sell these items. Still, the thought that replacing the LSD every 80K miles as routine maintenance isn't pleasant.

So... LSD-nerds... assuming the M's being driven by a non-track-although-aggressive-within-the-law street driver who doesn't drift

- How appropriate is Turner Sport's statement, i.e. IS the standard LSD in the E9x a part requiring regular replacement;

- How would a LSD numpty like me test if it did need replacement or do I just ask next time I take it in for a service; and

- If replaced, is there an LSD that provides similar cornering ability but with less (or preferably no) replacement?

I'm thinking that most, if not all, times I've gone around corners I've always had the rear two tyres on the ground, hence a torsen style LSD like Quaife may be a good way to go if I did have to replace. Perhaps my driving is so sh*tty that who cares if it "acts like an open diff"... be that as it may, I would appreciate any and all advice.

Finally, apologies in advance if I'm throwing in a match onto a dry tinder topic - it's not my intention to get anyone riled and, if so, it's done so out of ignorance.

Thank you.

[BanjoPaterson]

Originally Posted by driftflo

the wavetrac is a torsen-style atb (automatic torque biasing) unit which biases torque from one side to the other but is not able to lock the axle completely like any clutch-type lsd does.
and a torsen only locks... no, sorry... biases torque on accel and remains completely open on decel. so you have no stable rearend when braking or just lifting the gas.
in case of the wavetrac system you will have some preload compared to conventional torsen designs like quaife, who dont have preload.

so a torsen is a good diff for street driving but doesnt offer the performance of a clutch-type lsd unit. torsens are easier to drive for "normal" drivers as they dont lock/unlock but just smoothly transfer some torque. some supercars with massive torque output (i.e. gumpert apollo) use these units which extends the life of the bodyshell and typical driver of such a car ;-)

as our cars do not tend to be torque monsters and are really easy to handle, there is no need to get a supersmooth diff. and if you want such a smooth unit, it is already installed in stock config. the gkn viscolok is a "good" lsd which is pretty slow. the torsen is also quite "good", quicker than the gkn but with less locking capabilities. so if upgrading a quite well stock unit i would only opt for a really better, higher performing lsd system... and this only is the clutch-type one!

i hope i could explain it in an understandable way...?!

Hi Driftflo - this sort of answers my initial questions about which LSD a street driver would use if he/she needed to replace one on their M3, i.e. the standard gkn viscolok or even a [insert brand ?????] torsen LSD.

[redpriest]

Originally Posted by BanjoPaterson

First a disclaimer. I love that this thread exists and understand it about as much as advanced quantum mechanics... particularly after reading:

"...4 clutch upgrade with 45/45 degrees ramps in ZF 2way housing that would upgrade the locking precentage at 40-45%.."

However, if the LSD-nerds hang out here then this is the place to ask the questions bugging me. Because my car is leased, I can mod it/repair it/upgrade it on pre-tax dollars in preparation for buying it outright at the end of the lease. I've already done throttle actuators (replaced reduction gears with brass/delrin set); have a set of RBs in my garage awaiting March next year; and already replaced the DCT oil+pan+seals.

To my horror I saw a throw-away line that the LSD on the E9x M3 has a life expectancy of about 60-80K miles (!). A few people dismissed this, but on the turner sport website (https://www.turnermotorsport.com/p-3...=AQEBAQEB)they state:

"Limited Slip Options The M3's M Variable locking differential is genius when it's working properly. Unfortunately, as many M3 owners have come to find, the system only has a service life of 80,000 miles (sometimes less) and then the viscous unit inside starts to fail (is your's clunking?)."

Now - they probably have an agenda, somewhat, of wanting to sell these items. Still, the thought that replacing the LSD every 80K miles as routine maintenance isn't pleasant.

So... LSD-nerds... assuming the M's being driven by a non-track-although-aggressive-within-the-law street driver who doesn't drift

- How appropriate is Turner Sport's statement, i.e. IS the standard LSD in the E9x a part requiring regular replacement;

- How would a LSD numpty like me test if it did need replacement or do I just ask next time I take it in for a service; and

- If replaced, is there an LSD that provides similar cornering ability but with less (or preferably no) replacement?

I'm thinking that most, if not all, times I've gone around corners I've always had the rear two tyres on the ground, hence a torsen style LSD like Quaife may be a good way to go if I did have to replace. Perhaps my driving is so sh*tty that who cares if it "acts like an open diff"... be that as it may, I would appreciate any and all advice.

Finally, apologies in advance if I'm throwing in a match onto a dry tinder topic - it's not my intention to get anyone riled and, if so, it's done so out of ignorance.

Thank you.

Someone forgot to tell my car's diff that - 148k miles and no funny noises. 40 track days and zero problems. I drive the car over the limit quite a few times, and it's quite controllable and predictable. I've failed to catch a few and have the spins to prove it, lol.

[BanjoPaterson]

Originally Posted by redpriest

Someone forgot to tell my car's diff that - 148k miles and no funny noises. 40 track days and zero problems. I drive the car over the limit quite a few times, and it's quite controllable and predictable. I've failed to catch a few and have the spins to prove it, lol.

Given how I drive, my diff's probably going to last until the sun extinguishes itself...

Still, if it may need replacing in the future then any advice welcome!

[driftflo]

- How appropriate is Turner Sport's statement, i.e. IS the standard LSD in the E9x a part requiring regular replacement;

if someone calls the oe lsd "genius" i would not believe anything else this guy says about lsds in general
nevertheless they are not wrong about the oe diff wearing over time causing clunking noises while shifting. depending on the individual car, driver, oil change interval, ... this may occur earlier or later. three weeks ago i had a customer with a street driven 20k mile m3 who had these problems and was sent to me by his workshop. we switched to a clutch type unit (with anything else like bearings, gearset, driveshafts, ... remained untouched) and the clunking was gone afterwards.
it also depends on how sensitive the individual driver is. if someone with +100k miles on his car/lsd will change to a new unit he will massively feel the difference. as wear increases slowly over time a daily driven car never feels different from one day to another. so you get used to the clunking not remembering how it felt a few years ago.

- How would a LSD numpty like me test if it did need replacement or do I just ask next time I take it in for a service; and

as long as you are happy with it and have no performance or clunking issues there is no need to do anything with your rear axle (except an oil change maybe).
if you get annoyed by the clunking noises or simply want to improve the reaction of the lsd (and the whole car) with a noticably better unit you should change to a new clutch type unit.

- If replaced, is there an LSD that provides similar cornering ability but with less (or preferably no) replacement?

similar cornering ability you will only get with another (new) OE lsd unit. as the viscolok is pretty much the only lsd unit that performs that slow and special.
any other lsd unit will noticably improve cornering performance and reaction of the rear axle.
a freshly serviced or new clutch type lsd will last forever. only the locking performance will get weaker over time. but even if it is completely worn out and does not lock any more you will have no clunking or any other downsides (this problem is exclusive to the of lsd and some torsen units that tend to do some clunking over time too). a worn out clutch type lsd will behave like an open diff. but until this is the case you will need to do way beyond 150k miles.
on the other hand, if you have it rebuilt after lets say 100k miles you will feel the difference in locking performance.
so service interval depends on your demand on the performance. but if you are happy with your oe unit so far it seems your pretention is not too high

[driftflo]

Originally Posted by redpriest

Someone forgot to tell my car's diff that - 148k miles and no funny noises. 40 track days and zero problems. I drive the car over the limit quite a few times, and it's quite controllable and predictable. I've failed to catch a few and have the spins to prove it, lol.

i guess you have never driven a proper clutch type lsd... but if you are happy then don't try it! saves you a lot of money

people who only drive a 335i are happy with it. the first time they try a m3 they will know what they missed so far.

i always thought a m3 is a fast car with good straight line pace (until i drove a c63), good cornering ability (until i drove a gt3), pretty emotional (until i drove and fell in love with a 488gtb).
you know what i want to say?! there is always something better out there (that costs even more money). if you like and enjoy your m3 in the current config, stay with it. if you want to improve it, a lsd-change is a good point to go for!

[Sneaky Pete]

I had an issue during cornering with my 2013 low miles E92 M3 spinning up the less loaded inside wheel (in Euro MDM) causing the TC to kick in and power being reduced.
So I drained the BMW diff oil (Castrol syntrax LS 75w140 plus FM booster) and replaced it with standard Castrol syntrax LS 75w140...the difference was surprising, even within a day or two the tendency to spin up the inside rear wheel was gone and the diff locks up quite nicely.
I suspect the crappy BMW FM boosted oil ruins the way the car drives for a considerable number of owners who use it without needing to.

[driftflo]

Originally Posted by Sneaky Pete

I had an issue during cornering with my 2013 low miles E92 M3 spinning up the less loaded inside wheel (in Euro MDM) causing the TC to kick in and power being reduced.
So I drained the BMW diff oil (Castrol syntrax LS 75w140 plus FM booster) and replaced it with standard Castrol syntrax LS 75w140...the difference was surprising, even within a day or two the tendency to spin up the inside rear wheel was gone and the diff locks up quite nicely.
I suspect the crappy BMW FM boosted oil ruins the way the car drives for a considerable number of owners who use it without needing to.

sure... this is true... but nothing new!
the fm booster just reduces friction between the clutches...
you can choose between locking performance vs. quiet cornering!