Blackline helical LSD - any good?

[1536Z4]

So far so good with this Blackline unit this seems very good value for money.

Good to know

[Limonge]

Will post an update some time after it's installed!

Hello! After all this time, was it a good option? Would you buy it again? Any cons? I am seriously considering buying it

[autosport]

Little update chaps, yesterday I was at Brands Hatch. I was also at Brands ealier this year with the open diff, I can confirm the LSD unit makes a huge difference on track more noticable in and exiting the corners along with the high speed cornering. I've covered around 500+ miles with 100 of them on track, So far so good with this Blackline unit this seems very good value for money.

Awesome, am just installing at the moment, What Diff oil did you use (Weight and spec), Matt Lewis racing is just advising any good quoality oil but isn't providing a weigh or recomendation for Synthetic, semi synthetic, mineral etc..... thanks

[SDJ]

I followed the quaiffe fitting instructions which called for synthetic 75W 90 differential / gearbox oil iirc, but check. Tbh though, I can't see it making much difference whatever you put in there.
I drained it after 100 miles as suggested by blackline, but there wasn't any visible debris so wouldn't bother with that if doing it again.

[Joycey]

Little update chaps, yesterday I was at Brands Hatch. I was also at Brands ealier this year with the open diff, I can confirm the LSD unit makes a huge difference on track more noticable in and exiting the corners along with the high speed cornering. I've covered around 500+ miles with 100 of them on track, So far so good with this Blackline unit this seems very good value for money.

Awesome, am just installing at the moment, What Diff oil did you use (Weight and spec), Matt Lewis racing is just advising any good quoality oil but isn't providing a weigh or recomendation for Synthetic, semi synthetic, mineral etc..... thanks

As said above I just stuck some 75w90 in, no clutch pack to worry about. Done a further two more track days and its still on point

[autosport]

Awesome, thanks Guys.

We have a 4 hour endurance coming up, first chance to try it out
https://pheasantwood.com.au/pages/deputy-4hr-enduro

[B21]

If the Blackline diff is a copy of the Quaife LSD the choice of oil is important as the additives affect the performance of the diff…

https://www.birdsauto.com/sites/default ... 3%20v4.pdf

[Ed Doe]

If the Blackline diff is a copy of the Quaife LSD the choice of oil is important as the additives affect the performance of the diff…

https://www.birdsauto.com/sites/default ... 3%20v4.pdf

Precisely how do the additives affect the performance? It's a helical diff - it uses planetary gears, there are no friction/clutch plates which can be affected by fluid properties. Sure the longevity may be affected but certainly not performance of the diff. All the Birds technical doc says is it recommends either BMW or Titan 75W90 gear oil, and not to use additives or fluids designed to reduce fluid friction.

[B21]

If the Blackline diff is a copy of the Quaife LSD the choice of oil is important as the additives affect the performance of the diff…

https://www.birdsauto.com/sites/default ... 3%20v4.pdf

Precisely how do the additives affect the performance? It's a helical diff - it uses planetary gears, there are no friction/clutch plates which can be affected by fluid properties. Sure the longevity may be affected but certainly not performance of the diff. All the Birds technical doc says is it recommends either BMW or Titan 75W90 gear oil, and not to use additives or fluids designed to reduce fluid friction.

I’ve no idea how the impact of friction reducing additives affects it..but it obviously does otherwise why would they state it?

However according to this wiki extract friction is a key factor in torque control of this class of LSD..therefore I assure a friction modifier affects the torque management

Geared LSD[edit]

Audi Quattro Torsen Differential
Geared, torque-sensitive mechanical limited-slip differentials use worm gears and spur gears to distribute and differentiate input power between two drive wheels or front and back axles. This is a completely separate design from the most common beveled spider gear designs seen in most automotive applications. As torque is applied to the gears, they are pushed against the walls of the differential housing, creating friction. The friction resists the relative movement of the outputs and creates the limiting torque Trq d .

Unlike other friction-based LSD designs that combine a common spider gear "open" differential in combination with friction materials that inhibit differentiation, the torque sensing design is a unique type of differential, with torque bias inherent in its design, not as an add-on. Torque bias is only applied when needed, and does not inhibit differentiation. The result is a true differential that does not bind up like LSD and locking types, but still gives increased power delivery under many road conditions.

Examples include:

Torsen T-1 is the brand name of the original Gleasman differential invented by Vernon Gleasman circa 1949 (US Patent 2,559,916 applied in 1949, granted 1951).[7] The original Gleasman design was sold to The Gleason Works (later named Gleason Corporation), who started marketing it in 1982. The original T-1 model is incompatible with c-clip drive axles, which limited its use with many cars and pick-up trucks of the time. However, the original Torsen differential was used in racing by Mario Andretti and Paul Newman with great success.[8] All later worm gear LSD designs were derived from the original Gleasman differential. The T-1 is original equipment in the Audi Quattro, Subaru Impreza WRX STI, Toyota Mega Cruiser and AM General HMMWV "Humvee".[9]
Torsen T-2 was a new Gleasman design circa 1984 (US Patent application WO1984003745 A1)[10] that is compatible with c-clip axles. The new design, along with a merger creating Zexel-Gleason U.S.A. increased Torsen availability for OEM and aftermarket applications. Variants include the T-2R, which includes a Positraction style clutch pack that gives preload for racing purposes; and the T-3, a dual differential intended for AWD applications. The T-2 is original equipment in many high performance cars and pick-up trucks.[9]
Quaife differential, sold under the name Automatic Torque Biasing Differential (ATB Differential), covered by European Patent No. 130806A2. The Quaife version is most established in Europe and other markets other than the US, providing extensive aftermarket support for European and Japanese brand cars, especially front-wheel drive and all-wheel drive applications. The Mk1 & Mk2 (optional on later Mk3) Ford Focus RS used the Quaife ATB Differential as original equipment.[11][12]

[Ed Doe]

If the Blackline diff is a copy of the Quaife LSD the choice of oil is important as the additives affect the performance of the diff…

https://www.birdsauto.com/sites/default ... 3%20v4.pdf

Precisely how do the additives affect the performance? It's a helical diff - it uses planetary gears, there are no friction/clutch plates which can be affected by fluid properties. Sure the longevity may be affected but certainly not performance of the diff. All the Birds technical doc says is it recommends either BMW or Titan 75W90 gear oil, and not to use additives or fluids designed to reduce fluid friction.

I’ve no idea how the impact of friction reducing additives affects it..but it obviously does otherwise why would they state it?

However according to this wiki extract friction is a key factor in torque control of this class of LSD..therefore I assure a friction modifier affects the torque management

Geared LSD[edit]

Audi Quattro Torsen Differential
Geared, torque-sensitive mechanical limited-slip differentials use worm gears and spur gears to distribute and differentiate input power between two drive wheels or front and back axles. This is a completely separate design from the most common beveled spider gear designs seen in most automotive applications. As torque is applied to the gears, they are pushed against the walls of the differential housing, creating friction. The friction resists the relative movement of the outputs and creates the limiting torque Trq d .

Unlike other friction-based LSD designs that combine a common spider gear "open" differential in combination with friction materials that inhibit differentiation, the torque sensing design is a unique type of differential, with torque bias inherent in its design, not as an add-on. Torque bias is only applied when needed, and does not inhibit differentiation. The result is a true differential that does not bind up like LSD and locking types, but still gives increased power delivery under many road conditions.

Examples include:

Torsen T-1 is the brand name of the original Gleasman differential invented by Vernon Gleasman circa 1949 (US Patent 2,559,916 applied in 1949, granted 1951).[7] The original Gleasman design was sold to The Gleason Works (later named Gleason Corporation), who started marketing it in 1982. The original T-1 model is incompatible with c-clip drive axles, which limited its use with many cars and pick-up trucks of the time. However, the original Torsen differential was used in racing by Mario Andretti and Paul Newman with great success.[8] All later worm gear LSD designs were derived from the original Gleasman differential. The T-1 is original equipment in the Audi Quattro, Subaru Impreza WRX STI, Toyota Mega Cruiser and AM General HMMWV "Humvee".[9]
Torsen T-2 was a new Gleasman design circa 1984 (US Patent application WO1984003745 A1)[10] that is compatible with c-clip axles. The new design, along with a merger creating Zexel-Gleason U.S.A. increased Torsen availability for OEM and aftermarket applications. Variants include the T-2R, which includes a Positraction style clutch pack that gives preload for racing purposes; and the T-3, a dual differential intended for AWD applications. The T-2 is original equipment in many high performance cars and pick-up trucks.[9]
Quaife differential, sold under the name Automatic Torque Biasing Differential (ATB Differential), covered by European Patent No. 130806A2. The Quaife version is most established in Europe and other markets other than the US, providing extensive aftermarket support for European and Japanese brand cars, especially front-wheel drive and all-wheel drive applications. The Mk1 & Mk2 (optional on later Mk3) Ford Focus RS used the Quaife ATB Differential as original equipment.[11][12]

Sorry I have crossed my terms - to be clear the contents of gear oil (ie. the additives that manufacturers will be putting in) wont affect performance significantly. My point was in agreement with Birds technical sheet; don't put separate additives in, as this will affect the properties of the oil and potentially accelerate wear of the gears. Where

The problem with quoting wiki is that often it's not properly fact-checked and therefore often incorrect - this being a good example. Refer to the below video, which for clarity does not show the same layout of gears as a quaife, nevertheless shows how a Torsen Differential works - feel free to point out where, to quote wiki 'As torque is applied to the gears, they are pushed against the walls of the differential housing, creating friction. The friction resists the relative movement of the outputs and creates the limiting torque'. Hence this being my original point - Friction modifiers will not alter the performance of a Helical differential, they will however in all likelihood affect longevity of the gears/internals by altering the properties of the gear oil affecting the vicosity film strength or any number of other things.

https://www.youtube.com/watch?v=JEiSTzK-A2A

For reference - although showing fewer planetary gears than a Quaife, the below video shows how a Quaife or 'planetary type' helical Torsen Differential looks inside and operates;

https://www.youtube.com/watch?v=W96fOdMZnXE

[Madcatgrafix]

An interesting read, all 6 pages of this thread, but to throw a cat amongst the pigeons, give me a clutch plate lsd any day of the week. Apart from my z4, I also have a turbo'd mx5 mk2. I went from an open diff (crap), to a welded (crap, but fun), then a sport mazda torsen, then finally a kaz clutch plate. Now don't get me wrong, a torsen gear lsd, will lock, and you can power slide around a roundabout all evening long, but I don't like the very small amount of preload. The lack of preload will cause the diff to unlock, if you go through the transition of sliding 1 way to the other. A clutch plate diff always has preload, so the diff stays locked. The torsen having no preload worth talking about, will not put any power to the non spinning wheel, if the spinning wheel has no traction! Don't get me wrong, the torsen lsd was good fun, but my kaz clutch plate lsd, is even 'gooder' fun! Now after that speech, does anyone know where I can get a clutch plate diff for my e85 3l? (Kaz replied saying no, naw, non, no way sir-ee!)

[SDJ]

The wavetrac one is still geared, but supposedly stays locked https://wavetrac.eu/products/wavetrac-a ... 88k-r-3-15
It's almost 3x what I paid for the Blackline.

RacingDiffs do a plated version, not the cheap crap thing that goes inside the spider, but this:
https://racingdiffs.com/collections/rea ... 3159757986
3000 euro!

Or I imagine Drexler do a plated diff, but never checked with them.

[Ed Doe]

Drexler do plate diffs. That's what the M guys swap to when they get serious about track. I believe that's the diff of choice for Schirmer ring tool bmws. Cheap they ain't, but supposedly as you say they're just way better than any of the various torsen diff in terms of performance. In terms of daily driving manners, noise and service requirements however the torsen diffs are better. If that sort of thing matters to you

[DaveD]

Gripper plated diffs seem to have good reviews. Not sure anyone has put one in a z4 though

[plenty]

Bear in mind the likes of Gripper and Drexler need regular maintenance/rebuilds and can be clunky at road speeds.