Z4-forum.com

Does anyone have any experience of these? £620 delivered seems pretty good value to me...

https://www.ebay.co.uk/itm/122895977774

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

Edit, didn't realise the Quife bare diff was £919+ vat now

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

£560 delivered from http://www.mattlewisracing.co.uk/product.php/2475/

I'm well aware that you got a stonking deal on your quaife diff, 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)

What GuidoK said!

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-product ... ing-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

Interesting to have a couple thread resurrections by 1st posting newbies!

Darkangelv2 wrote: ↑Fri Aug 14, 2020 12:38 pm Interesting to have a couple thread resurrections by 1st posting newbies!

One of whom appears to have named themselves after a Neil Diamond song.

Song Shun Blue, everybody knows one.................

enuff_zed wrote: ↑Fri Aug 14, 2020 12:44 pm

Darkangelv2 wrote: ↑Fri Aug 14, 2020 12:38 pm Interesting to have a couple thread resurrections by 1st posting newbies!

One of whom appears to have named themselves after a Neil Diamond song.

Song Shun Blue, everybody knows one.................

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...

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.

GuidoK wrote: ↑Thu Jan 11, 2018 12:05 am A Quaife uses 6 sets of gears. More gearsets=stronger diff with less load per gear, so also less wear.

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.

Ducklakeview wrote: ↑Wed Jan 10, 2018 10:56 pm doesn't need the oil changing after 500 miles to "get rid of produced swarf" which will "decrease with use"

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 diff

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 wrote: ↑Thu Jan 21, 2021 10:27 am 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...

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..

booloveblankie wrote: ↑Thu Jan 21, 2021 10:27 am

GuidoK wrote: ↑Thu Jan 11, 2018 12:05 am A Quaife uses 6 sets of gears. More gearsets=stronger diff with less load per gear, so also less wear.

Yes and no. The 5 gearsets would likely be a larger module (size)

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 ). Unless the case wall of the diff is made eerily thin or the center gear is made smaller(=less strong)
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.

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.

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 (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

Ed.Straker wrote: ↑Thu Jan 21, 2021 1:14 pm Can't understand why they never fitted them to the higher power Zeds..

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.

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..