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

[spr]

Thanks I passed along to try the OS Gikken oil.

Originally Posted by dparm

In theory, yes, a thinner fluid might be noisier. If OS Gikken recommends 85w250, that's what I would run. I wasn't even aware something that thick was sold. You may also need even more friction modifier to quiet it down, but I would start with the proper gear lube first.

[driftflo]

this will not change the whining noise! they need to set it up properly.

[spr]

So are you saying that setup properly there will be no noise and it will sound identical to the stock LSD setup? Note I didn't change gearing, just LSD. Do you happen to have the backlash specs so I can check? Can I check same without removing it from the car or unbolting anything? I have a dial indicator with a mount so I can check the backlash say of the input shaft and side output flange hole. Thanks! It isn't that noisy now with the diff bushing removed but I can still hear it, especially under deceleration and downhill. Thanks. Otherwise, I do have to say that it is a huge improvement over the stock wasted diff!

[Simons]

hi driftflo,

you've mentioned that draxler LSD is the one used in gt4, am i right to say that draxler LSD is inside the gt4 final drive unit (bmw motorsport part # 8321819)?

and also just in case you may know - can i replace stock e90 m3 final drive with the gt4 unit mentioned above? is it plug and play?

many thanks

[driftflo]

Originally Posted by Simons

hi driftflo,

you've mentioned that draxler LSD is the one used in gt4, am i right to say that draxler LSD is inside the gt4 final drive unit (bmw motorsport part # 8321819)?

and also just in case you may know - can i replace stock e90 m3 final drive with the gt4 unit mentioned above? is it plug and play?

many thanks

yes and yes!

if you have a 6MT this is the weapon of choice... if you have an auto it will also fit straight in but the ratio (i=4.10) is too short!

is the 8321819 still available from bmw ms?
i thought they ran out of stock :-(

[driftflo]

Originally Posted by spr

So are you saying that setup properly there will be no noise and it will sound identical to the stock LSD setup? Note I didn't change gearing, just LSD. Do you happen to have the backlash specs so I can check? Can I check same without removing it from the car or unbolting anything? I have a dial indicator with a mount so I can check the backlash say of the input shaft and side output flange hole. Thanks! It isn't that noisy now with the diff bushing removed but I can still hear it, especially under deceleration and downhill. Thanks. Otherwise, I do have to say that it is a huge improvement over the stock wasted diff!

it should not make any noises that have not been there before! especially if you drive in a straight line. if you have a high locking and/or highly preloaded lsd it possibly makes some scratching noises when driving in tight turns. all other noises come from the r&p or more likely from the bearings. the reason is always a bad setup (wrong bearing preload, wrong backlash, wrong contact pattern).

backlash is measured like this:

should be around 0,10mm!

[Malek@MRF]

Originally Posted by spr

I just got the OS Gikken fitted to my e92. They also installed the turner solid subframe bushes and derlin diff bushes. However, there is CONSIDERABLE whine from 40mph up with the windows up. It is unreasonable at 80mph freeway driving. I dropped the car back to them to diagnose/fix it. Also they used just regular diff oil where Gikken stuff is 80w-250. Would this make a difference?

Is the diff not setup right or is it the derlin diff bushes or both? Do you have the spec for the differential backlash et al? Any help is appreciated. The sounds sounds like a poorly setup diff from my friends old mustang. Thoughts? Thanks!

Here is what I found for the specs. Can you confirm this is right so they can confirm setup? Also, they setup the backlash by feel, e.g. rotating the input shaft and flanges to feel the play. Sound screwy?

http://www.m3forum.net/m3forum/showthread.php?t=340871

Something isn't right here. With what the car is equipped with, the whine shouldn't be that noticeable the way you are describing. Was the differential internals done correctly? Backlash, etc...

[okusa]

Originally Posted by driftflo

yes and yes!

if you have a 6MT this is the weapon of choice... if you have an auto it will also fit straight in but the ratio (i=4.10) is too short!

is the 8321819 still available from bmw ms?
i thought they ran out of stock :-(

So then what is the ultimate setup for a DCT equipped car?

[driftflo]

Originally Posted by okusa

So then what is the ultimate setup for a DCT equipped car?

depends on the usecase of the car? concerning performance reasons i would go with a 3.62 final drive and a properly configured clutch-type LSD. of course i think my custom unit and setup is the best (this is why i do set it up like this) but it also depends on individual driver preferences on how the car should react and handle.

[okusa]

Originally Posted by driftflo

depends on the usecase of the car? concerning performance reasons i would go with a 3.62 final drive and a properly configured clutch-type LSD. of course i think my custom unit and setup is the best (this is why i do set it up like this) but it also depends on individual driver preferences on how the car should react and handle.

Thx. I'll pm you.

[NRBRNG]

Originally Posted by driftflo

depends on the usecase of the car? concerning performance reasons i would go with a 3.62 final drive and a properly configured clutch-type LSD. of course i think my custom unit and setup is the best (this is why i do set it up like this) but it also depends on individual driver preferences on how the car should react and handle.

100% agree. 3.62 in DTC is extremely rapid on track. Driftlow offers great advice and his custom option looks really great. He was really helpful in guidance for me. In the end I went with a more local (and therefore serviceable/ customizable ) option for my local shop guy with a Diffsonline 3.62 triple ramp. No issues with topping out of revs and you certainly bash thru the gears quickly. Mid corner and exit speeds onto straights is night and day difference. Definitely not a sensible option on a street driven car IMHO (noise, whines). Solid bushings is a must.
Thanks again Driftlow for the great community info and product offering!

[Simons]

hey driftflo,

thank you very much for your input, going to replace my almost dead stock final drive with #8321819 then
my local shop claimed to deliver it in about a month (so i assume they are out of stock but can still can be produced)

[driftflo]

so finally i found some time to disassemble, check and rebuild my new bacci lsd unit that i bought a few months ago when we collected a friends C63 gearbox at their factory in italy.



the internal design is pretty much like the zf/drexler units that i like the most anyway...






but it had quite much preload and the shallow 30° ramps activated. both options i dont like that much.

so i changed the setup to what i expect to handle better or at least better suits my taste. i removed the preload springs, added a clutchpack on each side, switched to own specially manufactured clutches and rotated the axles to the steeper ramps.






now i have to throw it in one of the rear axles laying around in my shop. and then i need to find time to fit it in the car. so i guess it'll take a while until i can tell you first hand how it actually feels like. although i dont expect too much surprises as all relevant parts are well know to me already.
anyway i'll keep you updated here...


by the way: it is the lightest of all units a had so far (9.6kg)... and the second most expensive short after the GT4 unit (eur 2.300,- incl. custom side axles).

[OM VT3]

Originally Posted by driftflo

so finally i found some time to disassemble, check and rebuild my new bacci lsd unit that i bought a few months ago when we collected a friends C63 gearbox at their factory in italy.



the internal design is pretty much like the zf/drexler units that i like the most anyway...






but it had quite much preload and the shallow 30° ramps activated. both options i dont like that much.

so i changed the setup to what i expect to handle better or at least better suits my taste. i removed the preload springs, added a clutchpack on each side, switched to own specially manufactured clutches and rotated the axles to the steeper ramps.






now i have to throw it in one of the rear axles laying around in my shop. and then i need to find time to fit it in the car. so i guess it'll take a while until i can tell you first hand how it actually feels like. although i dont expect too much surprises as all relevant parts are well know to me already.
anyway i'll keep you updated here...


by the way: it is the lightest of all units a had so far (9.6kg)... and the second most expensive short after the GT4 unit (eur 2.300,- incl. custom side axles).

What rebuild kit do you use?

[driftflo]

i do not use kits. i have several thousands of clutches from different sources or produced to my own specifications. so i use the parts that i think are the best for the certain application.
the clutchpacks i put in the bacci lsd are completely self-designed and produced to my specs. thicker moly coating with better surface finishing, harder steel...

[OM VT3]

Originally Posted by driftflo

i do not use kits. i have several thousands of clutches from different sources or produced to my own specifications. so i use the parts that i think are the best for the certain application.
the clutchpacks i put in the bacci lsd are completely self-designed and produced to my specs. thicker moly coating with better surface finishing, harder steel...

I mean for the diff itsself like bearings and stuff like that

[Hujan]

A little off topic, but I have some diff whine in my OEM diff since switching to solid subframe and delrin differential mounts. Not a huge deal, but I'm hoping to reduce it as much as possible. I'm going to give Redline Lightweight Shockproof gear oil a try. I'll try to report back with results. Might be something to consider for those of you with diff whine.

[driftflo]

i have all kinds of oe bearings (koyo, ***) in stock. as well as spacer discs for the lsd and pinion (custom made as no more available at bmw). i have them lasercut and shaved to the right sizes. shaft seals are still available from bmw.

[OM VT3]

Originally Posted by driftflo

i have all kinds of oe bearings (koyo, ***) in stock. as well as spacer discs for the lsd and pinion (custom made as no more available at bmw). i have them lasercut and shaved to the right sizes. shaft seals are still available from bmw.

Could you please pm me a price on the bearings and what ever else I would need to rebuild my diff?

[driftflo]

to rebuild the diff you need a lot of special tools. buying them to rebuild one diff does not make sense.
i'll pn you the prices for a set of bearings. if you need certain spacers you can have them from me as well... but you need to measure and tell me the size you need first. buying the complete sets would set you back some 100 $ :-(

[CSBM5]

Originally Posted by vagmag

Hello my friend .
I have send you also mail .

I have an M5 e39.
1) is it a direct bolt on swap the M3 OEM LSD to e39 M5 ;
2) how easy is to change the OEM 25% LSD to more lockup percentage as you mention you will do ?

Thank you

driftflo,

I'm curious about the stock E39 M5 diff also. Do you have the specs on it? I know it is a "weak" LSD from 12 years of personal experience with it including wearing out the discs (and stupidly replacing it with another OEM unit...but I got a price on a new unit that was too good to pass up). Does it have any locking on deceleration, or is it open? Ramp angles?

Thanks,
Chuck

[driftflo]

yes i have some m5 e39 units here. they come with only 2 clutchpacks and a 2-way setup which does 25% lockup on both, accel and decel.
and it has pretty much preload.

i developed a rebuild kit that fits plug and play with the double amount of clutches. so it locks 45% in both directions. clutches are higher quality than standard, too. if you want preload and/or even more lockup you need some exchange parts like different pressure rings, modified topcaps...
so the basic unit itself is a great basis but it comes as standard with a pretty low locking setup and wears out quickly.