Torsen LSD - Torque Transfer - Explained

[@sethwilliamson]

Great video! It might be helpful to point out that a limitation of the Torsen becomes evident. The differential can only transfer torque as a multiple (the bias ratio) of the wheel with least resistance. Imagine an airborne tire. It doesn't take much torque to turn an airborne wheel. Even if you have a bias of 6:1, six times "meh" can often be too little torque to overcome the static friction and make the vehicle move. An operator technique to address this limitation is found in your equation, F=μN. Once again we can add some friction. By applying the brakes, you add resistance. There's now somewhere for that torque to go--into your brake pads. That amount of force, multiplied by the bias ratio, is now available to the other side of the differential. Active traction control systems might use wheel speed sensors to detect such an event and automatically apply braking force to the free spinning wheel for you, but that's how you could do it manually.

[@EngineeringExplained]

Philosophy aside, could you be more specific? I never said I know all and make no mistakes (which is why you'll find notes and annotations throughout my videos, as I attempt to correct them with time). But you do realize there is a large difference between what speed a wheel spins at and what torque a wheel receives, no?

[@EngineeringExplained]

You are correct in stating they are not the same thing. Helical gear is basically a general term for gears which have the teeth positioned in a helix (rotating). This is different from spur gears, which are straight and not curved.

[@EngineeringExplained]

A 2 way does certainly lock more under deceleration than a 1.5 way, or 1 way (obviously). I do have a video explaining the differences of each. As far as changing the friction of a torsen LSD (not a clutch type 1.5 or 2 way) you could alter the amount of torque transferred between, but I don't believe this would not cause the differential to lock up under deceleration. It acts more like an open diff with small forces applied.

[@EngineeringExplained]

I think you're thinking of an STI. It's a sweet car with LSDs. Or an infection.

[@veoverse4286]

Thank you very much for making this kind of videos. I brought a torsen diff for my car and wanted to understand even better how it works exactly. Now I fully understand it. I have seen many videos from you and i like your explanations. I am glad that I already subscribed to you back then 😅

[@EngineeringExplained]

A slipping wheel sends torque to the opposite wheel (the one with traction). This is the definition of an LSD. A torsen diff handles it differently than others (as explained in the video) but the principle remains. The acceleration of the slipping wheel is a direct result of receiving torque with little resistance (friction) with the ground.

[@rttrippin]

I looked for hours to understand the torque transfer of this differential until this video. Thanks.

[@EngineeringExplained]

Probably cost, and clutch types have their advantages - adjustability of torque transfer, especially if they're electric. Also, if one tire's in the air a torsen is much like an open diff, where a clutch type is not. The new joint project between Toyota and Subaru has put a Torsen in the FR-S and BRZ. I think the Miata may have used it as well at some point (or maybe it still does?).

[@EngineeringExplained]

Thanks for clarifying, I appreciate the effort to help.

[@Sandy-oy2lr]

This video can really benefit with a working model. I had a SLP Torsen in my IROC-Z. It worked great unless one wheel totally lost traction. Then no torque would be transferred to the other wheel. However, if I straightened out the steering wheel, torque was instantly transferred to the wheel with friction. The Torsen acts like a 'one legger' when going around corners. But, then seems to act like a 'locker' when going straight ahead.

[@EngineeringExplained]

Not sure if I would generalize each that much. They each have their differences and benefits. Clutch types are very commonly used in racing; not sure how often viscous is as it may get too hot with extended use (this could be prevented with an oil cooler, Nismo toyed with this idea with the 370z). Torsen comes stock on the new BRZ/FRS.

[@EngineeringExplained]

Very welcome, glad it helped you out!

[@MissAlyayla]

Thank you so much for this video, I finally got the whole idea of the Torsen LSD! Keep up the good work!!!

[@MrNicholg]

clicked on another vid link that was supposed to be explaining the same, but just got more confused, but now, it all makes sense, thanks

[@EngineeringExplained]

Thanks, I'm glad you did as well.

[@spartanity]

+Engineering Explained Hey there, could you please link the detailed PDF file again? The old one seems to be dead now, thanks! And thanks for the video as usual, it helps a lot! Cheers!

[@EngineeringExplained]

Correct, applied torque can never exceed the frictional resistance.

[@DonTruman]

That one was pushing the limits of my capabilities but got the general idea. Seems sheer genius whoever dreamed it up. Two questions: 1. Is there any reason not to want the maximum possible Torque Bias Ratio? I.e., any benefit to having less? 2. What happens when there is close to zero resistance on one tire? E.g., on "black ice". Zero x 4 is still Zero.

[@Caelinb62]

1. the TBR being lower means you have less friction, meaning more efficiency 2. a 100% slip condition results in no traction (a car tire in the air means the other car tire can't move, effectively shifting the car into neutral). However, applying the brakes would give you less slip and hence traction.

[@mothabrotha]

Worth noting that when a vehicle drives through normal turn, both wheels have traction and therefore leverage over the differential. This leverage allows the diff action to take place and the drive wheels can rotate at different speeds. When one wheel is on ice it has less traction and therefore less leverage over the differential. Also, with a torsen diff, if a drive wheel has zero traction, (wheel leaves the ground) no torque can be transfered to the other wheel.

[@inorbit64]

Also in this video you say that there is deceleration torque bias while in the other video (where you are correct) you say that it does not work the other way. I understand it's very confusing, so I'm just trying to help. It's very brave of you to try to explain this stuff. But the torsen differential does not limit slip during deceleration. This is one of the reasons why clutch type lsd's provide more stability and better drift characteristics.

[@EngineeringExplained]

Ahh my apologies! I forgot to add it, it's there now. :)

[@samdouglas32]

As with so many engineering questions, the answer is "it depends". The Torsen differential is great for road cars. It's a big improvement over an open differential, they are low-maintenance and don't have significant handling quirks. A clutch LSD is preferred on sports cars, especially those used for competition or drifting. It won't completely lose traction if a wheel becomes unloaded, but needs regular maintenance and can cause understeer. Viscous .. ugh. Not on my sports car thanks ;)

[@pack_yak]

fantastic video! would really love to see a remake of this with how your current videos have progressed a bit from the white board in terms of production quality, and I'm not sure everyone grasps white board explanations as well as on a physical object

[@honda116969]

Agreed 💯%

[@jubuttib]

Depends highly on the application. Torsen can be quite durable and maintenance free compared to a clutch LSD, and it acts instantaneously whereas a viscous LSD takes some time to react to the speed difference. But torsen never truly locks, it can only transfer torque based on the bias ratio. So if one wheel is on super slick ice and can essentially handle no torque without slipping, the other wheel will only receive 5 times essentially no torque, which is still almost no torque.

[@rishabtomar9837]

the PDF link is not opening can u give other link for that...

[@DustinGould]

Yes the detroit locker is a different unit ------ but I was talking about the Detroit trutrack differential which is a torsion type

[@swde4793]

Sure, and I do understand the difference between TQ/speed. The answer is found in basic gearing. Numerically low ratio EG. (2:1) = higher speed/lower TQ. RELATIVE to a numerically high ratio EG. (4:1) = low speed high torque. Btw definitions are abbreviated. Explanations are specific.

[@hektikethnik]

If one wheel is in the air you can just apply the brakes lightly to create frictional resistance that the Torsen LSD can use to transfer torque to the other wheel.

[@yetanothermotherf]

IMO: -Torsen for slow heavy duty vehicles, say a tractor, as the torque transfer is constant regardless of speed. And due to rugged design, you wouldn't have to worry about burning clutches when massive input is applied. -Clutch for general purpose vehicles, say a pickup trunk, as it doesn't produce as much heat on higher (moderate) speeds. -Vicious coupling for sport cars due to its simplicity, small size and low weight. But it only works on high speeds. On slow speeds, it's practically "open".

[@gehtdianschasau8372]

Imho: Torsen, for maximum fun. Its not just for heavy duty vehicles, manny sports cars use them too.

[@DylanTimothyDean]

NICE seening a old video of yours! Been following for a long time thank you for the informational videos over the years and damn branding same intro same same nice! Just a little more foxy looking now i may say ahah! Keep up the great work

[@flashman_tv]

Torsen differentials were and are used by many carmakers in their racing models: Audi, Mazda, Honda, Subaru, Toyota ... - How could you miss this? A look at Torsen in Wikipedia reveals it.

[@swde4793]

I'm a firm believer in humility. It has has vastly expanded my knowledge base. I'm not afraid to begin arguments with others. Even when I know I'm wrong just so the debate itself will ask the right question. Finding truth. I'm not here to bring u down. Just respectfully advising to re evaluate, update and revise your knowledge. Just imagine how astronomers felt when some dude found out distant looking stars were in fact galaxies! Point is the world is much larger than u may realize.

[@BojanBojovic]

Brilliant! First of all the Torsen idea, than you videos.

[@EngineeringExplained]

No, it's quite different than a traditional clutch type LSD.

[@EngineeringExplained]

Okay, so what are you implying is inaccurate in my video?

[@R1CH4RD607]

Hi,Great video! I have a question. mathematically how you can calculate the TBR to design a differential? Regards.

[@jokatabg]

Torsen diff is locking only when the both wheels are on the same surface. If one of the wheels is on ice and the other is on tarmac this on the ice will start to spin and this on the tarmac will stop. Torsen is almost like ''Open diff '' . BUT the open diff is spining only one wheel even when they are on the same surface... Sorry for my english... :(

[@flashman_tv]

There is even friction between the flanges of worm- and helical gears, since they are especially made to be inefficient in this way.

[@Eletto22]

The detailed math pdf link leads to a page that “cannot be found.” Does anybody know where the pdf can be found??

[@DimitrisPatsouras]

wraios re brother gamw to emp mou mesa

[@6000cortes]

just bought an frs and they come with torsen lsd and that thing corners like no other!!

[@therealmacgyver5470]

so does a torsen differential have part that are supposed to wear like friction pads? if so then i prefer the visco LSD

[@OmgReaverDrop]

Hi Jason, I'm wondering, in this video Scion claims that the Torsen can deliver more torque from the slower-spinning inner wheel to the faster-spinning outer wheel during cornering (see latter half of v=u0EOrzn7-Qc?t=1m7s). If this were true, it would be good for cornering performance because that wheel has more weight shifted onto it and therefore more traction - but is this actually possible physically for this type of differential to shift MORE torque onto a FASTER-spinning wheel? Thanks!

[@UIMcocodog]

to my understanding its physically impossible. because a worm gear can spin a worm wheel but not the other way around it (in my non engineer mind) means that the faster spinning wheel can only ever cause more torque on the slower spinning wheel.

[@OmgReaverDrop]

Yeah that seems to be what I'm picturing in my non-engineer mind as well - that a Torsen serves to equalize the speed differential between the sides based on how it appears to work - similar to a VLSD (the VLSD being mechanically much more intuitive), but with better response and without the same overheating problem. Good when the two tires are on surfaces with varying coefficients of friction; not as useful when they are in a turn (contrary to what the video I shared claims if we are correct). Just wanted to be corrected or verified. Thanks for the response! Would love to hear other input too, either way.

[@eustatianwings]

A 2-way would lock more than a torsen, but the basic problem is that RWD performance vehicles oversteer under deceleration. There's nothing wrong with your car. I noticed in your "Euroing in wet" video you've got a ton of grip on the steering wheel, look at the tendons at the base of your thumb. That will amplify rear-wheel slip and encourage spinning. Apply smooth pressure but let the wheel turn out if it needs to. You'll get more control. Decelerating in a curve requires

[@realitytx]

Very good description, just what I wanted. When your body blocks the board it can be problematic. Perhaps you could use a pointer stick.

[@EngineeringExplained]

Or maybe lose a little weight, so you can see past my body. ;)

[@EngineerLikesFarming]

the audi quattro all wheel drive system has implemented a trosen differential since the late 80's till now

[@RetiOrchid58]

I guess all lsd's start with the open diff as their basic common denominator, and then modify for the locking scenario; but this one in effect starts with the locking scenario and modifies that for the open scenario.

[@fridaycaliforniaa236]

The Torque Bias characteristics now explain easily why the Torsen architecture is not a good choice for off-road : when you lift one wheel because of the terrain, the other will receive no torque at all.

[@Abbbb225]

Can you do please a video comparing a Torsen to a locked diff? What I am wondering is whether a Torsen type diff can end up sending more torque to the non-slipping wheel than a locked diff can. In the video explaining torque transfer in open vs closed diffs you calculated the force each tire could receive before slipping as a function of mu and N, but here you are factoring in the torque coming from the driveshaft (or rather, I suppose, the final drive torque? Please clarify that). In your example here, with a locked diff, would you get all 50 lb ft of torque to the non-slipping wheel, for a total of 55 lb ft, assuming the mu*N for the non-sloping wheel was at least 50 ft lb? Does it often happen that mu*N for the wheel with traction is greater than the (Torsen torque bias ratio)* mu*N for the slipping wheel, in which case it seems a locker would be better? Furthermore, can the Torsen diff multiply the torque at a slipping wheel to a value beyond the driveline input torque (the "initial" final drive ratio at ring gear/pinion gear interface)? If so, then just having one wheel slipping slightly would result in enormous torque for the non-slipping wheel. Is there a pre-load or minimum torque split between wheels for the torque bias ratio multiple to come into effect? Is that difference the torque bias ratio itself, such that, in this case, the Torsen diff will only multiply the torque at the slipping wheel by 4 once one that wheel is receiving at least 4 times less torque than the other, in which case the maximum torque it could deliver to the non-slipping wheel is the final drive torque? I would love to understand these points. They seem like subtleties, but really I think they are foundational to properly understanding how this works, and the pros and cons of a Torsen system vs a locking diff. I still don't understand which is capable of delivering more torque. It would be great if you could also compare locking diffs that can lock variably up to 100%, rather than just locking on or off - you make an LSD sound like this, but my understanding is that LSD's usually cannot give 100% lock, and are different from true locking diffs. Thank you.

[@EngineeringExplained]

+Abe Ramat A locked is capable of sending more torque (100%) than a Torsen. kzbin.info/www/bejne/oJ6QkIGZn9qhq8U

[@dsjr2006]

Can you do a demonstration of the different diff types on rollers? Like showing how a vehicle behaves with one wheel having low or limited traction?

[@gazevedojr]

Hello. The link regarding the pdf article is no longer valid. Do you have the pdf file to share with me?

[@nealesmith1873]

Very good explanations! It seems that with clutch packs, the wear will be at a rebuildable point, but with these, the unit will wear out in many places so it will have to be replaced eventually. What is the expected life of these units?

[@eugenespicer3272]

So metal on metal friction limits slip? I'm not sure I am comfortable with that.

[@EngineeringExplained]

But it's with justification, no?

[@Abbbb225]

1) Is the wheel speed in proportion to the TBR, i.e. if TBR of 3, is achieved, will higher traction wheel spin 3 times faster than lower traction wheel? I'm guessing no...wheels turn at same speed but with different torque? 2) Does a TBR of 3 mean that torque transfer (lock-up) will not occur until one wheel gets 3x less torque (has 3x less traction, I guess) than the other? 3) Does a TBR of 3 mean at least 3x or up to 3x torque is transferred (seems to be the latter).

[@EngineerLikesFarming]

the audi quattro all whell drive system uses trosen differentials since the late 80's till now

[@johnpooley3]

Hey Jason do you have that PDF?

[@simasm.7132]

Great video, however I have few questions if I may: 1) Worm wheel cannot rotate worm gear. That is how locking of Torsen works, isn't it? Why is then torque bias ratio isn't infinite? 2) I may not understand how torque travels in Torsen, but it seems to me, that in non-slipping turn it powers only inner wheel, is that right?

[@faverodefavero]

What is the difference between this and a Quaife Helical Mechanical ATB, please? Would really like to have those types of differentials (Quaife ATB style) explained...

[@Wiesenbo]

do you've found an answer? i want ro buy a atb quaife

[@Spacemonkey-]

Is this type of diff also referred to as a helical differential? Also the Quaiffe Automatic Torque Biasing Differential (ATB) is exactley the same as this? Im from UK so never heard of Torsen untill your vids. and another quick question so if any diff is labelled 1.5 or 2 way its a clutch or plated diff and not a geared diff?

[@EngineeringExplained]

Helical and torsen are different, here's a video on the different "way" diffs: 1 Way - 2 Way - 1.5 Way LSD - Explained

[@Spacemonkey-]

Engineering Explained yes i watched them and know what they mean and work with accel/decel etc but there was only talk of this with fricton plate clutches so im assume they all are that type, how does a helical diff work then ? next video! ;)

[@ulteamracing1]

+Engineering Explained Thanks for your videos. You do have a clear and easily understandable way of putting things. Not easy with this business! Could you explain the difference between an ATB quaife differential and a torsen (i fail to understand that difference). Second question, can the torsen "lock" if there is a significant grip difference between the two wheels?

[@MrBmxblur]

damn this video was freakin awesome. My professor should definitely have watched your videos before teaching us about this stuff...

[@tomasklony9544]

Hi, no idea if you gona reply but its worth the shot....i have a 4motion with centre torsen diff, if i would lock up the rear with hand brake the torsen would lock up the front, am i right? Because if yes and i would do that while going for a drift, i could possibly blow calipers or torsen itself, so i just want to be sure :D (sadly there is no way to disconnect the rear axle from transmission)

[@MrRafaKLS]

Do you know where could I find a detailed mathematical analysis of the way to transfer the torque of the slipping wheel to the opposite wheel? I really need it

[@inorbit64]

Thank you for the video. You made a mistake though in the explanation of the open differential. When there is only 5lb-ft of frictional resistance on the icy wheel, it will receive all the torque because there is virtually no resistance in the differential. So your pushing force is not 10lb-ft, but 5 lb-ft. Disadvantages of the torsen are high drivetrain losses and heat development in the differential due to the inefficiency of helical gear transfer.

[@jackiev4255]

Not true, open diff has a 50:50 torque split.

So the point is you can set a certain torque from the drive shaft at which the differential will lock, right? (Torque sensing means that it senses the torque from the drive shaft, if I get it right). How do you set the amount of drive shaft torque at which the differential locks? (So that it will lock for example at half throttle and not full)

[@F3ARL388]

Great work. Keep at it.

[@waltciii3]

Accelerating out of a corner does the majority of torque go to the inside wheel since it is the slower rotating?

[@yetanothermotherf]

My opinion was based on... The more solid moving parts there are, the more complex the system is, and thus more heat is produced. Or the system must be bigger and heavier in order to withstand the forces. Racing world is of course another game, where parts are made to last only one race. And (IMO) in BRZ/FRS, producing some 200bhp, you can use chopsticks as differentials (as in the friendly link you provided in the flick about differentials in general). PS.Some BRZ/FRS fan is going to burn me :D

[@brach661]

In theory does it mean a torsen will lock up if a very very sharp turn is made? does the torque bias ratio determine how much difference in wheels' RPMs before it locks up? thanks

[@2testtest2]

+Roger S If I understand this video correctly the torsen diff. will actually never really lock up. Also the speed difference between the wheels is not what makes the torsen diff. transfer torque, but rather the torque difference from the wheels them selves. So even if one wheel is turning really fast forwards and the other is turning really fast backwards, as long as they both have the same grip the torsen diff. will essentially act as a open differential. However even when both wheels are turning at the same speed, if one has less grip than the other, the one with more grip will get sent more torque. At least up to the torque bias ration is met.

[@An.Individual]

I think a Torsen diff effectively locks up when the TBR is exceeded. But I could be wrong LOL

[@NicholasWitham]

+Engineering Explained, what's the difference between a torsen diff and a truetrac diff? They both seem very similar. Which would be better on a 4wd vehicle rear diff, that does mostly on road, but still a fair bit of heavy off roading.

[@RX7GSLSEowner]

Cool thanks. Have a big-world-view question. The Torsen LSD would seem to be the best option of the three LSDs that you've presented thus far and it has been existence long enough for everyone to know about it, but yet I don't ever really hear anything about them. Only fleeting references. Seems like most all LSDs that I've come across are clutch type LSDs. Could be due to a lower manufacturing cost, dunno. But in the end the question is why don't we see more Torsen LSDs on the road?

[@DustinGould]

the detroit trutrack differential is one of these torsen LSD's I think Eaton owns the detroit name these days

[@aw4643]

Dont you think these would were out get ground down reduce friction metal shavings everywhere we know what happens when metal shaving fly around at high speeds or does this wereing down apply to every diff as much as any other diff

[@glamabilly]

To me, it looks like, because both axles are connected together by the spur gears acting on the worm gear and the worm wheel, for a decrease in speed by the inside wheel, there would be an equal increase in the speed of the outer wheel during a corner. If the differential was in the center of the axle, that would not be a problem, but with a diff offset to one side like in most front wheel drive cars, I could see a scrubbing action taking place as most likley the inside wheel will be spinning slightly too slow in relation the the ground than it should be. Do I have that wrong? The only other thing I can think of, is with the differential offset to one side, for the wheels to have perfect traction the input shaft of the transmission would have to spin a bit faster or slower depending on what direction the car turned meaning, lets say the diff was offset to the right, the engine would spin faster turnig right than left with the same vehicle speed. I'm on the verge of buying one of these diffs, but am confused by that tiny aspect. please answer this as I can find zero info about what I;m talking about.

[@mwmorph]

Price, demand and predicted usage. I know before this series of videos I had just a very cursory idea of what different types of LSDs are and why would I pay so much more for a Torsen? But Torsens are more common than you think, I believe most Audi quattros have at least 1 torsen center diff, HMMWVs I know come with them and a bunch of performance cars FWD and RWD do come with Torsens.

[@blackwolfhunter14]

I just watched every about differentials.. Wow! Thankyou Question: which, out of all the differentials you explained, would you prefer?

[@RetiOrchid58]

Very good videos, as always. How often are torsen diffs used today, and where?

[@rohitsidnale8872]

Can you please make video on helical limited slip differential T2 type

[@bobbeysharks]

Thanks for the explaination!!

[@biouhu3]

love your videos

[@PriyanshuP95]

Hey, it is really a great video.. :-) And can you please tell me what is the effect of type of differential ( open, lsd etc) if we are accelerating while having a turn... Like if a race car is having turn and also accelerating.. What type of differential should a race car use? And why?

[@EngineeringExplained]

Racing applications will likely use clutch type lsd.

[@PriyanshuP95]

Engineering Explained Thanx u so much for the answer and replying fast :-) .. And Can u tell me why clutch type?

[@MrNicholg]

+Priyanshu Pandey inside wheel gets lighter weight in a turn because of weight transfer, easier to spin inside tire, loses momentum, so limited slip keeps torque moving to outside wheel to maintain momentum and balance.

[@alexbeau348]

+Engineering Explained can you also tell about quaife lsd and different generations of torsen. corollas and celicas this type of lsd c-a.d-cd.net/baba548s-960.jpg

[@TheMikeHunt2]

What are the advantages and disadvantages of torsen vs viscous and 1/1.5/2way? I've being reading up on lsd's, and I've read some are pretty loud and low speeds (parking lots and such) which is lsd type is that?

[@chinmayb7069]

link to the pdf you said about, i'm sorry i couldn't find that one...

[@shahbaazali1195]

well well well , why is the ratio , i.e torque bias ratio 4:1 , what makes the ratio 4:1 , i am eagerly looking for the reply , thanx

[@eivtress]

Wow, I just got the awesome feeling of understanding.

[@EngineeringExplained]

Haha, took me a while to understand this one. :)

[@balabharathi7618]

Hi bro i can't find the pdf it say not found can u send another link

[@michaelbeary]

I can see how one wheel will spin faster than another as in a turn, but at point do they lock up? Does it happen when one wheel spins fast enough in relation to the other so that something different happens? It seems that either the wheels must turn in opposite directions in relation to each other, or they must move together. If one wheel is spinning like on ice, and the other wheel is moving at all - even inching ahead, then this will satisfy the requirement that they're moving in opposite directions in relation to one another. What mechanism then forces them to lock up when one wheel starts spinning?

[@ShawnDickens]

+mike beary When it is not a split that matches the ratio of the gearing inside (basically a math problem). So as long as they spin at that ratio in the difference that equals the ratio of the gears connecting the worm wheels it will run smoothly. When the ratio is off the worm wheel will try to spin the worm gear, but it can't. Think of it like a turbo being used in reverse. The exhaust is the gear on the axle or worm wheel. It can't turn the exhaust side or the worm gear. The wheels are made so they work with the air in one way so well with a steep angle that they can't work the other way. Just like this flowing air into the inlet side of a turbo will will not act on the shallow angle enough the turn the shaft and drive the exhaust side to do anything. The metal gear can't just flow like the air because it is locked on the shaft, so it locks up instead and turns it into a solid axle until things go back to normal. He goes over it at 5:00. The gears are two steep to go backwards like the turbo impellers.

[@jubuttib]

+mike beary It has to do with the resistance to rotation (aka grip) seen on both tyres, basically it starts "locking" when one wheel can handle less torque than the other one, even before any slip occurs. This is why these diffs are also called "torque sensing", they react when there's a difference between how much torque each side can handle, they're not speed sensitive as such. The torsen however isn't technically speaking a "locking" diff, it's a torque multiplier. With for example a 50 Nm preload-only diff you can always send 50 Nm more torque to the axle with more grip, so even if one tyre is on a theoretical surface with no friction at all, you can still put 50 Nm or torque on the other tyre. With a torque biasing diff like Torsen you can only multiply it by for example 4 with a 4:1 TBR, and since 0*4=0, with low enough grip it can still act like an open diff (in other words there's not enough resistance in the one slipping axle to provide any of the lateral forces on the worm gears to make them contact each other and cause friction). An AWD car with 3 torsen diffs in the front, center and rear can still at least in theory get stuck if one wheel is airborne.

[@seankagan5720]

can the worm gear move side to side on the axle? also why do I need to limit or lock the diff during deceleration/braking?

[@evgtorsen]

HI NICE EXPLANATION DO YOU KNOW ABOUT THE KNIGHT DIFFERENTIAL?? IT WAS DEVELOPED ABOUT THE SAME TIME THE RELEASE OF TORSEN BACK IN 1984 IS VERY INTERESTING AND WITH MANY ADVANTAGES COMPARE WITH TORSEN IT HAS A USA PATENT AND A BRITISH PATENT. WAS TESTED IN MC LAREN X3 CAR. ANY COMMENTS ABOUT??

[@TheDaftSmiley]

Excellent videos! Could you please make a video on chassis?

[@olafschermann1592]

As torsen differencials look muuuuch better than clutch based ones, are there any downsides?

[@Aditya-xn5xi]

I understood that the torsen differential is capable of differentiating the torque and the frictional contact points BUT 1. how does it actually transfer the multiple torque? and 2.what happens when the worm Gear is pushed linearly against the housing ?

[@AljazJelen1992]

Hey! I'm wondering, you've said that when you put in reverse (or just push the brake pedal) helix-spiral gears are pushed on the other side of differential. Does not that happen also when the speeds of left and right wheel aren't the same? I'm sorry for such a silly question but I'm also very interested in car mechanics and since none of this things are explained on faculty of engineering which I'm attending to, I just wander across youtube and workshops Sorry but I'm not so fluent at english :)

[@rkusuma6852]

based on how the gear, helix angle looked like. I guess it will not do what you have thought it will do. maybe it will just push on to the differential casing? or maybe it does do that? because as far as I know, there haven't been any sources citing that it will push on to the other worm gear if the speed difference is the opposite of what Engineering Explained has told us in his video.

[@MrAndrius12]

Wait so, F=mn dictates what exactly? What force has to overcome it and how does it dictate what happens?

[@NearCry91]

Does oil play a part in the torque bias ratio?

[@vts747]

Thank you again!

[@kapilramanujancbse]

IN your Future videos could you please explain about BMW's M- differential !!

[@BoostedVQUR]

All I know is I have a 16’ RAM 2500 6.7L 4X4 Laramie Longhorn with the “anti spin” differential. (Verified via window sticker and VIN lookup.) Anyway, I turn traction control off, power brake to ~10psi and then let her eat. Driver side leaves a DARK strip while the passenger side leaves a much fainter one. Reason I’m here… Haha!

[@nickamarit]

So a car that has 150 lb-ft of torque sent to the rear wheels would be able to send only 25 lb-ft of torque to the wheel on pavement if the wheel on ice could receive 5 lb-ft of torque for a TBR of 4:1... Does this mean that clutch pack LSD's are better because it would be able to send almost 100% of torque to the wheel on pavement even if the wheel on ice could receive only 5 lb-ft of torque?

[@btankoftitanium]

Can i use this kind of torsen diferential for a jeep wrangle unlimiTed

[@LC-qp7pr]

Doesn’t torque at the prop shaft have to equal the sum of the torque at the axles? In your open diff illustration, for example, you show 50 lb-ft at the prop shaft and 5 lb-ft at each axle. 50 lb-ft != 10 lb-ft. Isn’t this physically impossible?