TORSEN vs OPEN DIFFERENTIAL - TORQUE SPLIT simplified animation model 

This is about *TORQUE* , not power so it's your time to go back to school. Lesson for you about open differential: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-hsgAAQ5ZzG0.htmlsi=L_gXMje-vDT3c4B2

Thanks!

Lucky you! Four wheel drive cars are dangerous!

@@jerryl6634 Not if you know how to drive with one.

@@jerryl6634 why the f would they be dangerous.

This applies to all cars not 4x4

Is that wrong in terms of English language? 🙂

@@4x4.tests.on.rollers ha yes it's when i realised that it was a translate thing. the guy speaks perfectly so you notice it. Great video though!

@@rowanationer I think he used 20% as a reference because it would be easier to explain with the Nm values he used.

@@4x4.tests.on.rollers missing article "the " before accelerator

@@4x4.tests.on.rollers we understood you perfectly. Ignore these morons. Thanks for the great videos.

It does not. It will actually greatly increase traction capability for the vehicle while towing. Especially at boat ramps or any off road scenario.

Winter is coming, I'll think about that!

@@4x4.tests.on.rollers there is always mud

Yes, and due to asymmetric design it gives 70/30-15/85.

Quotation from technical docs: "In turning situations, the outside wheels of a vehicle travel over more distance than the inside wheels. Accordingly, the inside and outside drive wheels must rotate at slightly different speeds (i.e., differentiate) to maintain rolling traction with the road. A torque division between drive axles at the bias ratio is a precondition for differentiation under all circumstances of operation. Essentially, in order for one drive wheel to rotate faster than the other, the drive wheel having greater resistance to rotation slows with respect to the differential case and transfers torque to the other wheel contributing to its faster rotation. The Torsen differential resists transfers of torque between drive wheels in proportion to the torque applied to the differential housing, and this results in a larger proportion of the applied torque being delivered to the slower rotating drive wheel. Therefore, bias ratio should be selected to provide the maximum traction advantage that will still allow both drive wheels to deliver significant portions of engine torque in turns. However, even in turning situations, the Torsen differential enhances traction management. Since torque is already distributed in increased proportion to the inside drive wheel, it is exceedingly unlikely that the outside drive wheel will ever exceed available traction and 'spin up'. Alternatively, should the torque of the inside wheel exceed available traction in a turn, it is equally unlikely for this wheel to 'spin up' since such a 'spin up' would still require a difference in traction between drive wheels which exceeds the bias ratio. Ordinarily, when the inside wheel exceeds available traction, differentiation ceases and torque is divided in more even proportion between drive axles determined by the maximum torque that can be sustained by the inside drive wheel. Thus, in all directions of travel, the Torsen differential will resist 'spin up' of either drive wheel by instantly dividing torque between drive axles in proportions up to the bias ratio to match prevailing traction conditions".

@@4x4.tests.on.rollers thank you so much for the information 👍

But is it clear?

@@4x4.tests.on.rollers while I’m watching yes. It’s just easy to forget

Yes, of course, it applies to every application of torsen. Torsen never works like open differential, it is explained in the video (traction lost). Final result (only one wheel spinning) may be the same as with open differential but even then the torque split inside is very different.

Thanks for your relevant reply.

There are many cars which has torsen as a center diff.

@@4x4.tests.on.rollers nice i wanna see 1 :D

@@buder5116 Many of Quattro systems are based on torsen, you can find them on my channel 🙂

@@4x4.tests.on.rollers 4runners audi porche have center torsens

@@vadimnesen8060 Volkswagen, Alfa Romeo, Mitsubishi, Lexus, Range Rover, Chevrolet...

Hello, torsen is not a locking diff: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-qrBPpHhUdTY.html

Zgadza się, tak jak i otwarty dyfer. Aczkolwiek w najnowszych wersjach torsena są tarczki cierne, ale nie wiem jak się to ma do hamulców.

No tak, ale chyba w otwartym d. Hamulce mają więcej roboty (dla tego samego efektu muszą zadziałać silniej).

@@krys8870 Tak, zdecydowanie, chociaż to też zależy jaki TBR ma torsen.

If one wheel is in the air then there's just a small value of torque needed to spin it. And even if this value is multiplied by TBR, it is still too low to spin the other wheel.

@4x4 tests on rollers channel thank you! This is what I was looking for. So need to find other option for offroading .. as usually we have one wheel in air

The situation you described is a job for front and rear differentials. These diffs are usually open, including Amarok, so everything is up to effective traction control system.

You mean replacing open by torsen? You can do rear, you can do both.

@@4x4.tests.on.rollers Thank you for your prompt response!

No, the point is that it is not possible to apply 70, not enough resistance.

@@4x4.tests.on.rollers how does people use torsen on their driftcars then? 🤔

@@trippychips I'm not in a drift thing but I suppose that they may be using torsen with high TBR ratio.

It's 30. If traction is lost then there is less resistance. Engine cannot generate more than the resistance (grip) allows. If you apply 50% then the only result will be faster spinning of the wheel with no grip.

@@4x4.tests.on.rollers Thank you very much! I've always confused about this, but now I understand. If the engine is just spinning without attach to any thing at 5000rpm, it's only delivering power but 0 torque right? Wish your channel grow to 100k soon😃

@@franklinchen2898 Right 🙂 Well, zero is the theoretical value cause there is always some resistance but torque is very low. Thanks!

Jeśli będzie miał wystarczająco wysoki TBR....

Cuz if you say no even with Electronic diff lock rear right tire will get %15 torque at max scenario car Electronic differential lock has no use

Torsen has advantage for the scenario if left tire has max %20 torque limit not to slip, then 1:3 ratio torsen can send %60 power to the right tire but with edl max torque of right tire can be max %50 cuz this is an open differential

Hi, I do not understand your question. Any value above 15 for the left tire means slippage. If you apply brake to the left tire then you will increase the max value from 15 to 20 e.g. (brakes prevent from spinnning). So open diff will split 20/20 (max 40 from the engine) while torsen up to 20/60 (max 80 from the engine).

@@4x4.tests.on.rollers if car has edl since max torque split of one tire can %50 with open diff, then car can able to send %50 of the power to one wheel and brake other %50 powered wheel to %15 to avoid the slip thats what i am saying

@@ozkanugurcetin2842 You can't "brake to 15". You have to "add" braking force and traction together. This will be one, increased value. And the same value will go to the right if it is an open diff. I will do another animation about it :)

There is kind of "initial lock" (up to TBR level), so torque is transfered asymmetrically if there is traction difference between left and right wheel.

Kind of a static fiction inside the diff that has to be overcome before the wheels can spin at different speeds?

@@daniel.dybvik Yes. It is clearly stated on torsen website and in some detailed technical descriptions from late '80s which I used for this video.

@@4x4.tests.on.rollers thanks for the clarification :)

Somewhat confusing because you are thinking like a clutch-style LSD. Torsen or Truetrac, as soon as the wheels turn enough for the worm gears to react to a speed difference the torque split happens. Near zero. That is why a little parking brake can allow you to crawl out of a one wheel up situation.

No, we don't 🙂 That is torque sensing diff, not speed sensing.

@@4x4.tests.on.rollers Awesome, love to discuss the matter! With torsen, can you please elaborate at what stage before the wheel slip does the torque split happen and what mechanical element decides which side gets more torque. With love, S

@@samin2173 The answer is in the video 🙂 Any stage above 15 units on the left wheel (so any above 30 units from the engine). When it comes to mechanics - that's more complicated, generally all elements...

At 2:05, I bet my hairy old dog that torque coming from crankshaft, the torsen rear diff cannot pre-see which side will slide. Yet you are stating that it can. It cannot. Therefore other side will slip first, then the worm gears with worm wheels will do their thing. The torsen thing. But you cannot state that torsen is pre-emptive, because it is not.

@@samin2173 Torsen is "locked" up to its TBR ratio. That's why it won't slip as soon as open diff. That's not any "pre-see" but initial "locking" effect. Everything is clearly stated on torsen website. Locked diff would do the same, you could even apply much more torque in such situation and left side would get only 15 (its TBR is infinity:1).

Torsen or lsd are not lockers, they won't behave like welded diffs. They may limit speed differentiation between the wheels but not lock them.

@@4x4.tests.on.rollers I mean, what if the limit is too high?

@@jaromirandel543 That must be some really strong lsd, designed for some special purposes.

@@4x4.tests.on.rollers O.k. Thanks.

There must be a resistance too apply torque. Wheel which is already slipping has less resistance then before traction is lost, that's why torque decreases.

The dynamic friction coefficient is smaller than static friction coefficient for smooth or relatively smooth surfaces. Dynamic=when the surfaces slide (wheel spin). However, on high snow and moderate mud, at higher spin, the coefficient increases again probably because the centrifugal force throws the snow/mud from between the tyre profile pattern.

@@rotorblade9508 Or the tyre diggs deeper to the surface with better traction 😉

@@rotorblade9508 Thank you for the explanation that has so physics exactly:) for that reason ı can understand.

@@4x4.tests.on.rollers Thank you so much. I love your every video these are so specific:))

Idk is it torsen or someone similar .i dud some research and i guess limited slip

1:45

Video is about torsen and open diff rules, if someone is wondering how that works as a center diff - just say in your head "front axle" instead of "right wheel" and "rear axle" instead of "left wheel". When it comes to xDrive - it doesn't have center differential.

duszaniespokojna - 4x4 tests on rollers yes you are right. It’s called a transfer case, I thought it had a differential mechanism. Anyway it should perform similarly, not like an open differential but more like an lsd.

@@rotorblade9508 xDrive is Actimax (with some exceptions) from Magna Powertrain and actually it can lock itself.

duszaniespokojna - 4x4 tests on rollers thanks, Yes. I just watched some animations with the xdrive and the torsen with the worm gears. So the xDrive has a locked rear and front torque is controlled through clutch plates.

To zadanie dla TC, EDL, BDL i całej masy innych nazw dla systemów wykorzystujących w tym celu układ hamulcowy 🙂

@@4x4.tests.on.rollers Tutaj bardziej myślę, aby wykorzystać przekazywanie momentu przy wyłączonych systemach bezpieczeństwa :). Nie sprecyzowałem, ale dzięki za tak szybką odpowiedź!

@@patrykwitkowski2806 W wielu dzisiejszych samochodach nie da się ich całkowicie wyłączyć. Ale otwarte dyfry wracają do łask z uwagi na rozwój elektroniki.

@@4x4.tests.on.rollers W moim z tego co wiem jest taka możliwość. Mowa o BMW E90 :). Problemem jest właśnie otwarty dyferencjał, przez co uślizg tylnej osi jest bardzo ograniczony i lepiej własnie to wychodzi z uśpionymi lekko systemami, gdzie hamulce będą ładnie dohamowywać. :)

I am under the impression that the engine drive torque is split equally when open differentials are used. Is that right or is load torque split equally?

@@jasvirvirdi6744 Engine cannot create torque if there is no resistance. Resistance comes from grip. Less grip means less torque can be generated. Torque split of an open diff is always 50/50, value is limited by the wheel with less grip.

@@4x4.tests.on.rollers Thank you! I will read a bit more on this

Because traction is lost so friction coefficient goes down.

Yes, but in a much simpler way. They also create heat and friction when not necesarry on full grip surfaces.

@@melody3741, Heat is a consequence of friction, and friction is the basis of the blocking effect. It doesn't matter how friction is created, what matters is its presence. All lsd are the same in this. Unfortunately, they all have low friction on ice when needed, and high friction on pavement when not needed. This is due to the magnitude of the moment transmitted through the mechanism. The only difference is the preload. it is an attempt to correct the characteristic by creating friction when needed. But there are Torsen with preload, and for example, cam lsd without preload.

Purpose?

I agree it is but also interesting. The video is very simplified :-)

@@An.Individual Values are simplified, not the rules 🙂

@@4x4.tests.on.rollers good video. I will share it. You didn't mention that you can use ABS brakes to trick it to transferring more torque. I love mine in my F-150.

@@fabulousoffroaddesigns5080 Thanks. ABS/brake intervention will be in separate video some day 🙂

Video is about torque split, not power split.

Not correct, that's a common mistake. Torque split of an open differential is always 50/50 (TBR 1:1). What varies is the rotational (angular) speed thus the power, not the torque. Torque split of a spool or locked differential is from 100/0 to 0/100 what means that all the torque can go to one wheel while rotational speed of both wheels remains the same. This video should help: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-hsgAAQ5ZzG0.html When it comes to torsen - it is explained in the video what will happen when traction is lost. That's not the same as open differential but the final effect may look the same.

I understand what you are saying and agree, but in practice the power to the wheel with traction can fall to zero, such that the theoretical torque directed to the wheel with traction is meaningless because it has zero power.

@@amschind OK but the statement that _open differential will direct all torque to the wheel which has lost traction_ is completely false. What will happen when one wheel has zero traction is explained in 1:37. There's no theoretical torque directed to the wheel with traction, there's a real torque but with value limited by the wheel with no traction.

I don't get your point. In this simplified model the amount going from the engine equals the amount on both rear wheels (sum). And in case of open differential 50% of torque goes to the left and 50% to the right. Always.

This video is about TORQUE split, not POWER split. Power= torque x angular velocity (revolutions). Open differentional always has 50/50 torque split. And torque can be on a fixed wheel too.

@@4x4.tests.on.rollers True to your statement, however check your video at about 1:40, You say when 30Nm is produced from the engine due to loss of traction, power drops to 26Nm from the engine, Now power output from the engine does not in way rely on the traction of any of the wheels

@@edu.g6082 Everything is correct in the video. Listen to the full sentence and its correlation with animation, not just two seconds long part. If still something is not clear - please precise your question.

@@4x4.tests.on.rollers I REST MY CASE. Let somebody else be the judge.

Nothing is wrong. Engine cannot create more than the grip allows.

@@4x4.tests.on.rollers sorry, but you don't understand how the Torsen/Truetrac works. Your video is partially correct, but also very wrong.

@@totaldla I understand it very well and I think you don't. But if you think I am wrong - explain it. FYI - video is entirely based on information provided by JTEKT and technical specifications of torsen from the 80's.

No, there is no mistake. Torque split of open diff is *always* 50/50. Value on wheel with grip is limited and equal to value on wheel without grip. Locked diff has 50/50 torque split only when both wheels have the same traction and load.

@@4x4.tests.on.rollers i have open diff on my blazer. Its more like 100% traction on the passenger side, always. Period. Driver side NEVER turns under any circumstances. I know that its always 50%50% but it definitely doesn’t feel that way when you’re sitting there in ice or rain and one tire just spins.

@@resistorstudios That's the problem. Tire with good grip gets the same amount of torque as tire on ice. That's why only one spins.