Blackline helical LSD - any good?
- Thread starter C8H18
- Start date
Chinese manufactured I believe with a 12 month warranty.
Not that much cheaper than a Quaife, for what seems to be a relatively unknown brand?
The Quaife comes with a lifetime warranty, and doesn't need the oil changing after 500 miles to "get rid of produced swarf" which will "decrease with use"
Mike
Not that much cheaper than a Quaife, for what seems to be a relatively unknown brand?
The Quaife comes with a lifetime warranty, and doesn't need the oil changing after 500 miles to "get rid of produced swarf" which will "decrease with use"
Mike
Edit, didn't realise the Quife bare diff was £919+ vat now :x
Not that they come up often, but I'd prefer a used Quaife myself, I paid £750 for mine fully built up with only a couple of hundred miles on it. At least I know if I break it through abuse, they'll cover it..
Mike
Not that they come up often, but I'd prefer a used Quaife myself, I paid £750 for mine fully built up with only a couple of hundred miles on it. At least I know if I break it through abuse, they'll cover it..
Mike
Looks cheap.
The two halves are held in with 5 bolts.
Quaife uses 11 (although less thick).
MFactory diffs have 9 bolts.
First of all more bolts are either stronger or spread the forces more evenly.
Also I think that 5 bolt pattern probably uses 5 sets of helix gears. I suspect that an Mfactory diff also have 5 helix gearsets (as they sit between a set of bolts, and on this diff they sit between 1 bolt). But this is a speculation, I've never
A quaife uses 6 sets of gears. More gearsets=stronger diff with less load per gear, so also less wear.
Let me explain:
Parts from a quaife diff:
2 halves where the helix gears sit:
As you can see there is not much room to place the bolts that hold the two halves together. 11 bolts almost automatically mean 6 sets of helix gears (6x2=12 but 1 bolthole is used up for a dowelpin (locating pin))
An Mfactory helical lsd for a bmw has 9 bolts:
That almost automatically means it has 5 sets of gears
This see through picture from mfactory self also displays that:
How much gearsets this diff has? who knows. The bolts sit in a peculiar place where normally gearsets sit.
It could even be a 3 gearset diff; they exist too (and have enough space to locate the bolts in that space):
And this is just the technical design.
Who knows what kind of material they've used. Cast steel? Billet? (quaife is billet, mfactory is forged)
Obviously if you have a larger diff you can fit more helix gears, but this is a 1:1 comparison for bmw 188k diffs; that mfactory diff pic comes from e46fanatics (so also a 188k diff)
The two halves are held in with 5 bolts.
Quaife uses 11 (although less thick).
MFactory diffs have 9 bolts.
First of all more bolts are either stronger or spread the forces more evenly.
Also I think that 5 bolt pattern probably uses 5 sets of helix gears. I suspect that an Mfactory diff also have 5 helix gearsets (as they sit between a set of bolts, and on this diff they sit between 1 bolt). But this is a speculation, I've never
A quaife uses 6 sets of gears. More gearsets=stronger diff with less load per gear, so also less wear.
Let me explain:
Parts from a quaife diff:
2 halves where the helix gears sit:
As you can see there is not much room to place the bolts that hold the two halves together. 11 bolts almost automatically mean 6 sets of helix gears (6x2=12 but 1 bolthole is used up for a dowelpin (locating pin))
An Mfactory helical lsd for a bmw has 9 bolts:
That almost automatically means it has 5 sets of gears
This see through picture from mfactory self also displays that:
How much gearsets this diff has? who knows. The bolts sit in a peculiar place where normally gearsets sit.
It could even be a 3 gearset diff; they exist too (and have enough space to locate the bolts in that space):
And this is just the technical design.
Who knows what kind of material they've used. Cast steel? Billet? (quaife is billet, mfactory is forged)
Obviously if you have a larger diff you can fit more helix gears, but this is a 1:1 comparison for bmw 188k diffs; that mfactory diff pic comes from e46fanatics (so also a 188k diff)
What GuidoK said!
Mike
Mike
Hello. I was trying to find some info on Blackline LSDs and i found this post. Not much out yet, I read GuidoK post and what I can see on pictures of Blackline LSD its 5 bolt = 5 gear sets. And they are use 8620 steel http://www.interlloy.com.au/our-products/case-hardening-steels/8620-case-hardening-steel/ it seams to be a good choise of material to use in a diff.
Would have been interesting to hear from someone that have use one. From the spec or picture it seams good. A quaife you know what you get but this is cheaper and i could think of trying one.
Regards/ Patrik
Would have been interesting to hear from someone that have use one. From the spec or picture it seams good. A quaife you know what you get but this is cheaper and i could think of trying one.
Regards/ Patrik
Interesting to have a couple thread resurrections by 1st posting newbies! :spy:
enuff_zed said:
Maybe these lads can arrange for a forum discount?
I'd be happy to have one fitted in exchange for an impartial review.
Hi all,
Might be a first time poster but saw some misinformation posted here and figured I could clarify some things - especially given the thread has already been revived... :roll:
I bought a Blackline 188K after umming and ahhing as it's a lesser known brand and has the typical "chinese made" bad rap. It's getting installed in my 130i on Monday so I can't give any usage feedback yet - but I am a mechanical engineer with experience in custom manufactured gear sets so I figured my comments and pictures might be useful.
Firstly, this is almost an exact copy of the Quaife diff posted above. It has 11 (not 5!) radial bolts + 1 dowel for locating. The only evident difference I can see comparing my photos to Guido's is that the Blackline diff has full threaded fasteners whereas the Quaife fasteners have some shank remaining.
Apparently I didn't take any exterior photos except for when I immediately took it out of the box - didn't expect to be documenting this for posterity! Don't be fooled - the photo on the box doesn't match the supplied diff.
On the whole, the machining is good but they have evidently struggled with deburring. Where the bottom of the gear pockets broke through the exterior of the housing the steel has chipped very brittlely. These did not get fettled or deburred prior to assembly. It wouldn't have any effect on the performance of the unit but it bothered me enough to pull the diff apart - if for nothing else to tidy these pockets up a little.
Before:
After:
The other half of the housing evidently had similar issues when being drilled but Blackline did deburr these holes internally. Results aren't great but they're not the end of the world.
Hope this has cleared some things up. Definitely a case of getting what you pay for in regards to the overall finish of the diff, but I can't see any reason why these issues would affect the functionality. Assuming their steel is forged 8620 and their heat treatments are within spec this should be a great addition to my car! Frankly, being a tight bastard, I'm pretty happy to have saved the money compared to buying a Quaife diff. If I were to buy another I would consider the MFactory unit - it was my other key option but a little more expensive and wasn't instock locally anyway. I haven't seen any disassembly pictures of those so hard to say how they compare.
Will post an update some time after it's installed!
Might be a first time poster but saw some misinformation posted here and figured I could clarify some things - especially given the thread has already been revived... :roll:
I bought a Blackline 188K after umming and ahhing as it's a lesser known brand and has the typical "chinese made" bad rap. It's getting installed in my 130i on Monday so I can't give any usage feedback yet - but I am a mechanical engineer with experience in custom manufactured gear sets so I figured my comments and pictures might be useful.
Firstly, this is almost an exact copy of the Quaife diff posted above. It has 11 (not 5!) radial bolts + 1 dowel for locating. The only evident difference I can see comparing my photos to Guido's is that the Blackline diff has full threaded fasteners whereas the Quaife fasteners have some shank remaining.
Apparently I didn't take any exterior photos except for when I immediately took it out of the box - didn't expect to be documenting this for posterity! Don't be fooled - the photo on the box doesn't match the supplied diff.
On the whole, the machining is good but they have evidently struggled with deburring. Where the bottom of the gear pockets broke through the exterior of the housing the steel has chipped very brittlely. These did not get fettled or deburred prior to assembly. It wouldn't have any effect on the performance of the unit but it bothered me enough to pull the diff apart - if for nothing else to tidy these pockets up a little.
Before:
After:
The other half of the housing evidently had similar issues when being drilled but Blackline did deburr these holes internally. Results aren't great but they're not the end of the world.
Yes and no. The 5 gearsets would likely be a larger module (size) so would comfortably make up for the increased load per gear by having stronger individual gears. Plus you can always move to a stronger material to increase your gear strength. There are many types of steel to choose from with wildly varying strengths.GuidoK said:
That's indicative of the gears not being run in. Most gearsets will have some sort of run-in process to self-tolerance the gears. No manufacturing process is 100% perfect so there will always be minor amounts of filings coming off as the gears mesh for the first time. As the gears continue meshing, particularly under load, the surface finish gets smoother and gear geometry matches closer and closer. If you're expecting big curls of swarf, you'll be disappointed. Maybe Quaife and MFactory have a run-in process at the factory. Maybe they superfinish their gears. Doesn't bother me much regardless, it's hardly difficult to do an oil change on a diffDucklakeview said:
Hope this has cleared some things up. Definitely a case of getting what you pay for in regards to the overall finish of the diff, but I can't see any reason why these issues would affect the functionality. Assuming their steel is forged 8620 and their heat treatments are within spec this should be a great addition to my car! Frankly, being a tight bastard, I'm pretty happy to have saved the money compared to buying a Quaife diff. If I were to buy another I would consider the MFactory unit - it was my other key option but a little more expensive and wasn't instock locally anyway. I haven't seen any disassembly pictures of those so hard to say how they compare.
Will post an update some time after it's installed!
booloveblankie said:
Great explanations, thanks for your input. Looking forward to seeing the outcome once you've had it installed.
Might be a good solution for a simple road car swap. Would imagine the Quaiffe and Mfactory units are a bit pricier as they have more QC checks and a run in period as you suggest, would certainly explain the price difference to this unit.
Cheers
I have the utmost respect for the (original) designers of these devices..I struggle to even comprehend the concepts..
Great that there are people who understands these things and can debate them..
Coming from many Audi Quattros over many years I'm a great fan of torque sensing diffs!!!
Can't understand why they never fitted them to the higher power Zeds..
Great that there are people who understands these things and can debate them..
Coming from many Audi Quattros over many years I'm a great fan of torque sensing diffs!!!
Can't understand why they never fitted them to the higher power Zeds..
No they won't. The size of the gears is limited by the width of the diff and the size of the internal gear. That stays the same whether one uses 3, 4 5 or 6 pairs of helix gears (look at the 3 gearset example in this topic :wink: ). Unless the case wall of the diff is made eerily thin or the center gear is made smaller(=less strong)booloveblankie said:
In this case using less gears doesn't mean you can use bigger gears. So more gears will always result in a stronger, longer lasting product if materials and tolerances used are the same and you maximize the available space.
I suspect that quaife has figured this out long ago and for this diff size 6 gearsets is the optimum (with smaller or larger diffs this of course might be different). They have a very long history in motorsport (even F1) so I suspect they've mastered this as well as the next one.
That goes for all the gears. Who say's another manufacturer hasn't already used one of the strongest steels. Especially if that manufacturer sells more expensive products and has a way longer reputation in high performance products.
There is always a point that you can not move to a stronger material :wink: (and you usually get what you pay for)
Btw your diff looks pretty much a 1:1 copy of the quaife unit. I wouldn't be surprised if the gears would match.
Be sure to follow the fitting procedure for those bolts :wink:
They have (LSD's that is). The z4m has an LSD (albeit it works on a different principle, it is speed differential actuated instead of torque bias). And now the new g29 m40i has a torque vectoring lsd. The last time bmw fitted torque bias LSD's was in some variants of the Z3 afaik.Ed.Straker said:
GuidoK...I was aware that the E85 Z4M had some sort of LSD, I was referring to the more powerful turbo charged E89s..I would have thought with the substantial mid range torque of those newer generation turbo charged engines that a LSD would have been a useful addition to help what appears to be the documented way would behaviour of the more powerful versions?
Realise this topic was in the E85 section but was very interested in this topic..
Realise this topic was in the E85 section but was very interested in this topic..
Ed.Straker said:
Z4's are pretty much parts bin cars. As the e89 rear axle is very much based on the e83 X3 rear axle, for that platform there is no LSD available in the bmw parts bin. Therefore no LSD for the E89 (factory fitted that is). Just like there is no factory fitted lsd for the non M e85 platform (e46 based).
The Z3 has been fitted with lsd's as that uses a modified e30/e36compact rear axle. Lots of LSD's for that rear axle achitecture.
Sourcing an external supplier to develop an lsd and factory fit it is generally way to expensive, certainly for the Z type cars as their salesnumbers are dwarfed by the other models.
GuidoK said:
Thanks for the insight
Liverpool
Only in horsepower. The turbo models usually have a lot more torque though (e.g. the 35is/40i have about 100lb/ft more than a Z4M) - which is where an LSD would help putting the power down.abar121 said:Thanks for the interesting analysis. Any idea how a Wavetrack LSD would compare?
The Z4M remains the most powerful Z4 produced, if only on paper
It's lb.ft, not lb/ftmmm-five said:
the engine torque itself is not really an issue. It's wheeltorque that breaks traction, not enginetorque. So gear ratio's have to be taken into account.
Just the difference in final drive (2.56 vs 3.65) is huge.
In fact, to my information, the maximum wheeltorque (stock, factory data) put down is greater for the z4m (5748Nm) than for the 35is (5507Nm) (not taken drivetrain losses into account). And of course the z4m is quite a bit lighter too.
Btw the difference in max. enginetorque between the 35is and z4m is according to BMW 85Nm (63 lb.ft)
And the 40i has an LSD :wink:
