Blackline helical LSD - any good?
- Thread starter C8H18
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Why not just start a new one then?Andres said:
abar121
Active member
GuidoK said: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:
Exactly. Torque is amplified by the gearbox, to give tractive force at the rear wheels. You need to make torque fast (power), to take advantage of this. Is like the 335d owner's boasting that chipped motors have more torque than a C63, but then forgetting that they have to run gearing that is ~1/3rd longer. So you can take that off the tractive force, straight away.
This is commonly mis understood. Have a read here. https://www.onpointdyno.com/understanding-torque-and-horsepower-lets-try-this-again-with-tractive-force/
This extract from https://www.automobile-catalog.com/model/bmw/z4_e89.html which shows a number of published data and computer simulations encapsulates the discussion..
BHP wise the 35is and the Z4M are closely matched..according to BMW the Z4M has 335PS vs 340 PS for the 35is and 355nm vs 450nm
The graphs superimposed show how they line up..
So as was stated if you run both cars through the gears then they are closely matched with the Z4M edging out the 35is..
So what does that big torque number give lower down?
If you look at the acceleration roll ons without shifting down then the 35is fairly significantly tramps over the Z4M?
BHP wise the 35is and the Z4M are closely matched..according to BMW the Z4M has 335PS vs 340 PS for the 35is and 355nm vs 450nm
The graphs superimposed show how they line up..
So as was stated if you run both cars through the gears then they are closely matched with the Z4M edging out the 35is..
So what does that big torque number give lower down?
If you look at the acceleration roll ons without shifting down then the 35is fairly significantly tramps over the Z4M?
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There is of course also another big difference between the z4m and e89, and that is that traction control systems have gotten way better in that generationdifference, and still continue to improve.
So in real world performance differences they play a huge role.
In a modern powerful rwd car, if you can switch off traction control, you will not get close to setting a performance acceleration time (on normal street/street tyres) to the one set with traction control on.
However, if I take my car (e85 ph1, but modified), when traction control kicks in, it costs me at least 0,5 sec or more as when it interferes, it pretty much switches off the power delivery and you almost hit the windscreen with your head... So for me, the best acceleration times I get is when I feather the throttle about 50% in first.
So besides the z4m having an LSD and the 35i/35is doesnt, it also probably needs it more, as it prevents traction control kicking in (in real life situations).
Same goes for esp; the e89 esp system is much more advanced than the e85 esp system. The e85 esp/tc systems are pretty much 1st gen, developped in the mid/late 90's (e46 platform)
The g29 goes a step further; it's LSD is a proper torque vectoring unit, so actively improving cornering.
Because the e85 esp/tc system is so bad, an lsd very much improves the normal spirited driving (with all the safety's on), as it pushes the boundries where those systems start to interfere. Like the slipping of an inner wheel when driving away in a corner normally immediately sets off the traction control, taking away all the power abruptly in the e85. The LSD prevents that.
So in real world performance differences they play a huge role.
In a modern powerful rwd car, if you can switch off traction control, you will not get close to setting a performance acceleration time (on normal street/street tyres) to the one set with traction control on.
However, if I take my car (e85 ph1, but modified), when traction control kicks in, it costs me at least 0,5 sec or more as when it interferes, it pretty much switches off the power delivery and you almost hit the windscreen with your head... So for me, the best acceleration times I get is when I feather the throttle about 50% in first.
So besides the z4m having an LSD and the 35i/35is doesnt, it also probably needs it more, as it prevents traction control kicking in (in real life situations).
Same goes for esp; the e89 esp system is much more advanced than the e85 esp system. The e85 esp/tc systems are pretty much 1st gen, developped in the mid/late 90's (e46 platform)
The g29 goes a step further; it's LSD is a proper torque vectoring unit, so actively improving cornering.
Because the e85 esp/tc system is so bad, an lsd very much improves the normal spirited driving (with all the safety's on), as it pushes the boundries where those systems start to interfere. Like the slipping of an inner wheel when driving away in a corner normally immediately sets off the traction control, taking away all the power abruptly in the e85. The LSD prevents that.
abar121
Active member
The US Z4M has 335ps, the Euro version 343ps.
The traction control on the M is quite primitive as mentioned. On the plus side, it's not overtly sensitive like an E39 M5, so you can drive it pretty hard and have some slip angle, provided you keep it balanced. On the road anyway and so not too intrusive and easy to work with. But then it won't save you if you are really ham-fisted.
On the track, forget it and turn it off. You can enable the M track mode, which some people find useful at least.
The 35is is DCT only, which weight penalty aside, really helps the acceleration figures. Being an auto with 7 gears, there's not relevance in comparing any in gear figures really. Who's going to do that? Just kick the bugger down!
The traction control on the M is quite primitive as mentioned. On the plus side, it's not overtly sensitive like an E39 M5, so you can drive it pretty hard and have some slip angle, provided you keep it balanced. On the road anyway and so not too intrusive and easy to work with. But then it won't save you if you are really ham-fisted.
On the track, forget it and turn it off. You can enable the M track mode, which some people find useful at least.
The 35is is DCT only, which weight penalty aside, really helps the acceleration figures. Being an auto with 7 gears, there's not relevance in comparing any in gear figures really. Who's going to do that? Just kick the bugger down!
North West Surrey
Ed.Straker said:
True, but if you use the right gear the M makes the 35is look a bit sluggish!
And hopefully you don't buy an M with a manual gearbox to be in the wrong gear when you want to make some progress - I certainly didn't. :lol:
BTW the graphs show the M as 343PS and the 35is as 340PS, rather than what you quoted at the start of your post.
And back on topic the M has an LSD, the 35is doesn't!
samuelee46328i
New member
[ref]booloveblankie[/ref], hi you have news ? i need a lsd188k and i want know if blackline is a good choise !!
booloveblankie said: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.
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!
Excellent post, thank you
I've just fitted one of these. Got it delivered for £523 with 10% off. Quality seems really good. Fitting isn't an easy DIY, but with some decent bearing pullers and a hydraulic press was able to swap the original bearings over. No shimming was required as the backlash was fine. You do need to grind the original case for clearance to manoeuvre it in, but that's the same as a quaiffe.
Only one test drive done so far and it's brilliant. No funny noises or vibrations and goes sideways beautifully on a greasy roundabout
https://www.mattlewisracing.co.uk/product.php/2898/0/limited_slip_differential_bmw_1_3_series/815ce93f97bdaf647243eff7db1f5bc5
Only one test drive done so far and it's brilliant. No funny noises or vibrations and goes sideways beautifully on a greasy roundabout
https://www.mattlewisracing.co.uk/product.php/2898/0/limited_slip_differential_bmw_1_3_series/815ce93f97bdaf647243eff7db1f5bc5
did someone say that the oem traction isnt completely rubbish? i cant for the life of me think of a more interfering unit. making any personal best runs an impossibility if left on. (thats on the dry ofcourse, in the wet i have no idea as i dont think ive *ever* driven my car in the rain.. but in the dry... its nice to keep on for a warmup lap, but then its gotta go.. hmm maybe the traction control on my mums C220 is worse...
absolute rubbish system that traction control in our e85/86. :x
combine that with the fact that if you lift off the trottle a bit abrupt, it pre pressurizes the braking system , youve got 2 systems that i cant fathom for the life of me why they would have included those on the zed... anyways, you can disco the traction, sadly you cant correct the brake system, unless you remove it completely.
(slightly OT, but thought id add that in as it came up a few posts ago)
interested in a review of that copy LSD
absolute rubbish system that traction control in our e85/86. :x
combine that with the fact that if you lift off the trottle a bit abrupt, it pre pressurizes the braking system , youve got 2 systems that i cant fathom for the life of me why they would have included those on the zed... anyways, you can disco the traction, sadly you cant correct the brake system, unless you remove it completely.
(slightly OT, but thought id add that in as it came up a few posts ago)
interested in a review of that copy LSD
Nothing funky happens on my regular 2003 3.0.
I always turn the TC off when larking about obviously, so not an issue for me. Plus there's quite a lot of traction and not that much power anyway, so driving with the TC on isn't a big problem in normal driving.
I'm enjoying the greasy roads at the moment though
I always turn the TC off when larking about obviously, so not an issue for me. Plus there's quite a lot of traction and not that much power anyway, so driving with the TC on isn't a big problem in normal driving.
I'm enjoying the greasy roads at the moment though
Hi folks, apolgies for the massive delay!
Long story short - my 130i got driven into by a truck, fought my insurer for a bit, fought my repairer for a bit, and am now (still!) arguing with the insurer over a year on from the incident...
So it's taken me a little longer to put mileage on the LSD than I'd hoped but I've done a couple thousand kms now with a good mix of city, country and spirited driving so am confident enough giving an opinion.
Do I recommend this LSD?
Absolutely! It is a night and day difference in rear end grip on acceleration. Traction control kicks in a lot less and I generally have much more confidence to accelerate into traffic, around corners, etc.
Haven't been doing any skids around roundabouts but it does leave two nice black lines when launching hard...
How is the car to drive?
The consequence to driving dynamics is that the car is much less neutral in cornering. The ability to use the throttle to steer is a little unusual at first but you get used to it. Applying throttle will induce a little understeer but that's a known characteristic of LSDs on RWD cars.
I got caught out at first by having different diameter tyres left to right (had a puncture previously, didn't want to change both... Wasn't an issue with an open diff :? ) which caused the car to turn during straight line acceleration too but sorted that out quickly enough.
Is there a downside?
The one thing that maybe counts as a negative which is a little gear whine when hovering at constant speed - most notable around 50km/h. It's by no means overly loud but it's not silent like the open diff. (No, it's not diff bearings. Those were replaced when the diff was.) Some of you gearheads will probably think it's cool (because racecar )! I don't find it to be of concern and most people I have in the car don't notice it unless I point it out.
Overall I'm very happy with the purchase and happy to recommend to others.
Long story short - my 130i got driven into by a truck, fought my insurer for a bit, fought my repairer for a bit, and am now (still!) arguing with the insurer over a year on from the incident...
So it's taken me a little longer to put mileage on the LSD than I'd hoped but I've done a couple thousand kms now with a good mix of city, country and spirited driving so am confident enough giving an opinion.
Do I recommend this LSD?
Absolutely! It is a night and day difference in rear end grip on acceleration. Traction control kicks in a lot less and I generally have much more confidence to accelerate into traffic, around corners, etc.
Haven't been doing any skids around roundabouts but it does leave two nice black lines when launching hard...
How is the car to drive?
The consequence to driving dynamics is that the car is much less neutral in cornering. The ability to use the throttle to steer is a little unusual at first but you get used to it. Applying throttle will induce a little understeer but that's a known characteristic of LSDs on RWD cars.
I got caught out at first by having different diameter tyres left to right (had a puncture previously, didn't want to change both... Wasn't an issue with an open diff :? ) which caused the car to turn during straight line acceleration too but sorted that out quickly enough.
Is there a downside?
The one thing that maybe counts as a negative which is a little gear whine when hovering at constant speed - most notable around 50km/h. It's by no means overly loud but it's not silent like the open diff. (No, it's not diff bearings. Those were replaced when the diff was.) Some of you gearheads will probably think it's cool (because racecar
)! I don't find it to be of concern and most people I have in the car don't notice it unless I point it out.Overall I'm very happy with the purchase and happy to recommend to others.
Hi booloveblankie, glad you are enjoying the diff, I certainly am. Did you install it yourself and measure the crown wheel backlash?
The Blackline part of the diff doesn't do anything when going straight ahead so won't be causing any whine, but if the pinion and crownwheel don't have enough backlash it will whine. The backlash is set with different thickness circlips on the side bearings. If you look at them they have the thickness marked on them, which is why you mustn't mixed them up left to right.
I was lucky that my new diff gave just enough backlash, a little less than the original one removed. You can't easily buy the circlips, but you can buy shims more easily apparently, if you have too much backlash, or machine some material off.
With regards to the car pushing/understeering a bit underpower i haven't noticed it much, but when i fitted an lsd to my M135i this happened. Once you are used to getting harder on the power earlier the balance comes back though and you can 'steer from the rear', although not so easy in a e85 due to the lower power. Biggest benefit for me is that is breaks traction in a nice predictable way
The Blackline part of the diff doesn't do anything when going straight ahead so won't be causing any whine, but if the pinion and crownwheel don't have enough backlash it will whine. The backlash is set with different thickness circlips on the side bearings. If you look at them they have the thickness marked on them, which is why you mustn't mixed them up left to right.
I was lucky that my new diff gave just enough backlash, a little less than the original one removed. You can't easily buy the circlips, but you can buy shims more easily apparently, if you have too much backlash, or machine some material off.
With regards to the car pushing/understeering a bit underpower i haven't noticed it much, but when i fitted an lsd to my M135i this happened. Once you are used to getting harder on the power earlier the balance comes back though and you can 'steer from the rear', although not so easy in a e85 due to the lower power. Biggest benefit for me is that is breaks traction in a nice predictable way