we need more people like these in schools. Most teachers/professors just follow the book to the dot and then students become like brain-dead robots. When you could put more effort in it, understand the book yourself, and explain it to the students in a much more simpler and effective manner. I appreciate people like these man
My next car will likely be an STI actually, so I guess that answers your question. I love hatchbacks, I think the STI sedan looks boring. From a performance basis, the EVO can probably put down better track times, but it's not hatch and loses so much practicality. Also, the next gen STI is supposedly going to shed some weight, and possibly come in 2 door. I'm a big fan of 2 doors.
Well it depends on throttle position, but to answer your question in a simple manner, yes. You put a constant A/F ratio, but that doesn't mean that the amount of air that comes in is constant. Increase the amount of air (by designing for optimum flow, or adding forced induction) and you must then increase the amount of fuel burned.
Honda's full time sh-awd uses multi electromagnetic clutch packs that are integrated into the rear differential. When taking a fast turn, the clutches that are associated with the rear outside wheel tighten up. This inevitably causes 100% of the torque/power to transfer to that one rear wheel, and no power to any of the other 3 wheels. Kind of causes a "peg leg" or row boat effect (rowing outside oar only). Pretty cool and sophisticated system.
Oh I don't know. It's all about the application, they all work. But do you want full engagement (good for off-road) or do you want to allow slip (great for on road)? Or do you want partial slip with torque transfer (viscous coupling)? All just depends really, they each have a purpose for sure.
It allows for some difference in speed between the front and back. When the speed of one exceeds the speed of another it transfers torque, but this does require a difference in speed, which makes cornering on pavement doable. Kinda the same principle as a torque converter, when you step on the gas, your engine is spinning faster than your transmission, but they are linked.
Well, it's symmetrical. Unlike the one I have shown, the transmission is placed longitudinally, so all of the components are balanced as far as weight. And a viscous coupling is used to transfer torque to the tires with more grip.
I would love to see a video where you discuss AWD vs FWD in terms of traction and safety to help decide if it's actually worth the additional cost when purchasing a vehicle.
If you haven't watched my video on transfer cases that's a great resource to check out. After that I'd look to any documents relating to your vehicle, to see what the actual set-up is. Glad you like the videos!
Yes, the back would get 5 lbft UNTIL the viscous coupling/locked diff began to spin. If the differential was locked, and the front tires are spinning, that would mean the rear tires are also spinning; so you'd either be moving, or burning all four tires.
Yeah, this drawing of this kind of setup would ONLY apply to the FWD biased "auto" 4WD systems that use either the viscous coupling or the electronic clutch pack to send power to the rear, but NOT to the one with a center differential, because if you have a center differential, (whether with or without an attached viscous coupling, which only makes it a limited slip diff.), then in that case your drawing would have to be changed completely, because in order for a diff to work properly you have to feed the diff. first from the transmission, (and not the front wheels directly), and then and only then, the torque would transfer through the front and rear outputs of the diff to the respective front and rear diffs and axles... As in how Subaru and a few other of the more "symmetrical AWD" systems work... You should make another video explaining this major difference between the two major types of systems, (i.e. FWD biased like this and ones with a center diff)!
Yeah this explanation isn't bad, but it does only seem to illustrate the honda civic wagon and honda crv awd systems. To be fair though as many different setups as auto manufacturers have come up with you'd have to make quite a lengthy video to cover everything.
do you know why in this setup a rear diferential with a gear reatio is used? because apparently it receives traction from the front wheels after passing thru the front diferential
Some sort of differential yes, you wouldn't want a locked mechanism that wouldn't allow for separate speeds. I was just saying it's possible to have a direct drive.
Yes, you could see gains by reducing the amount of driving wheels. It is better in that all of the weight of the car is on the driving wheels, so you can accelerate quicker if you are traction limited without AWD.
I guess it would still depend on how much power they have, how much grip, and where the weight is located. AWD will allow for a faster start, but it means more losses from the engine, so it could still lose over a 1/4 mile if they all have the same engine. RWD could be second after AWD, as weight transfers to the back upon acceleration, meaning it could put down more power, but FWD typically has the least amount of drivetrain loss. Any of them could win depending on differing characteristics.
Yes, but it's purpose is to get them to rotate at close speeds, to eliminate the disadvantage of an open differential (one set of tires spinning, the others stationary).
Depends on the center diff of the 4WD vehicle. If it's locked, then the 4WD vehicle has the advantage, if it's open, then the AWD vehicle has the advantage, and if it's an LSD then they are about equal.
Well, for one it's actually symmetrical, as in when you look at it from above the vehicle, shafts and diffs and the whole system is basically mirrored if you cut the vehicle in half. I don't believe this is very common, most are offset one way or another.
Hey Jason, the way you figure a mid differential is incorrect. A diff is always driven on the outer ring (those 2 gears you connected to nothing are actually sitting on a ring) and outputs torque on both left and right, or in this case, front and rear. You cannot just put in a diff anywhere in the axle, it has to be where front, rear and driven axle meet.
Power is created by turning the chemical energy of gasoline into heat, and using that heat to create mechanical energy. If you want more power, you must burn more fuel. Or you can improve the efficiency of the engine/driveline/reduce rotational masses, but ultimately it comes down to more fuel.
I was just watching a video from Borgwarner about Haldex systems. The central differential that some Audi's use. It might be worth doong a video on this system. It is a pretty cool setup and this one uses a centrifugal lever system.
Is a transfer case an integral component of any AWD set up? If so, why is it not part of this vid? Besides, if the Bevel gear is always there, doesn't that mean that torque will always be transferred to the middle shaft regardless of the AWD type? How can a viscous coupling grant a 50% transfer of torque when fluid is included? Too many questions. I have to admit, I'm starting to get a little confused since the 4WD vid. Maybe I'm rushing things. However, I can never thank you enough for such great explanation; it is the reason I'm eager for more knowledge about automotive technology now. Thank you, Jason!
just wanted to point out what i believe was said incorrectly. The differential serves to allow left (or right wheels) to spin faster or slower than there counterpart when navigating a turn. This is necessary to prevent slippage of the inner tire, as it will not travel as large of an arc as the outer tire. In the video it said front and back wheels spin differently. Let me know if I'm wrong. Thanks for the video!
The front and rear wheels also have to spin differently. It's the same as you'd find on a front/rear axle, only it's not the 2 side wheels connected to it, but the front and rear driveshafts
Hello, I'm really impressed with all your good explanation, that makes complicated subjects easy to understand. Now, I have a request if you could please explain how quatro sports differential work. Thankyou!
A great way to demonstrate how a viscous clutch works in your own home is to take an egg (a raw egg), and spin it on your counter top, grab it and stop it and immediately let go, it will continue to rotate due to the inertia of the viscous fluid (yoke) inside exerting friction on the shell, without any outside torque applied. If you were to apply external torque, there's a viscous clutch.
Why there aren't avaliable any cars (wagons or sedans) equipped with 3 locking differentials? Yes, subaru has nice awd drivetrain, but I wonder that subaru legacy has 3 locking diffs - that would help them in off-road situations.
DCCD (Drivers Center Controlled Differential) are good, you can use them off road, on corners by powering more power to rear wheels and then as you exit power more power to the front to exit, also 50:50 split for rain would be good, 70:30 for a good launch in racing, I want an awd car that does this like a wrx sti or something.
I should add one more "AWD" system. For the past 15 years or so, full-size GM pickups and SUVs have used a part-time system with push button controls. If you were to examine those buttons, one would be labelled "AUTO". Auto mode is RWD unless the computer spots slippage. The vehicle, for the most part, could probably be left in Auto unless you need LO (which is present) or you're low on fuel.
I understand how differentials work when it comes to splitting the power between two wheels but I don't understand what the center differential in your drawing is doing. :/
Yeah, he has it drawn wrong for a differential based system... This drawing really only applies to the FWD biased systems that use either a viscous coupling or an electronic clutch pack to send power to the rear... A center diff would have to be fed engine/trans. power first, and then from that it would go out to the front and rear, and in that case, the front would *not* be fed directly first, as he has it shown here!
@@JoeJ-8282 he is describing the 3 main different types of AWD systems. He just simply drew it all on one picture and described each individually. He clearly explains that they are completely separate systems and that they are all not on any vehicle.
Two important points: Your diagram shows the centre differential having its input coming from the front differential. The input to the centre differential should be from the output of the gearbox. There should then be TWO outputs from the centre differential: one to the front differential and one to the rear differential. AWD vs 4WD is a vague marketing term about the style of vehicle (heavy or light duty offroad), not the drivetrain itself. My 'AWD' Forester has high and low range.
Slightly tangential subject - if you have a viscous coupling - if the unit is punctured either by striking a rock etc on the road or in military terms a mine or IED punching through the armored belly of the viscous coupling unit - can you have a viscous fluid (as in self sealing fuel tanks) that self seals itself on contact with air - to give a sort of TV science example the same way as custard creates a solid skin or is able to temporarily act like a solid when absorbing energy?
My car is a standard, it has front engine with FWD, but since it was made in different models, it still has higher floor in the middle.. possible shaft placement? Could i install a shaft & viscous coupling, or should i not bother, old Volvo V50.. can probably just buy another with AWD.. but since there is a tunnel.. ? :)
I believe the viscous coupling produces a 50/50 split in normal operating conditions. I could be wrong, but in my car (with viscous couplings F + R) it "feels" AWD... all the time.
I have a question, does the placement of the differential determine power output? For example I have seen rear wheel biased systems, and when I see the front differential it is usually on one side. Does the side that is closer to the front differential get more power
Plz explain 4wd system in 2017 hyundai tucson 2.0 disel which comes with centre differential lock. Hyundai calls it intellimatic 4wd system. Pls explain how does it works. And is that system helpful on road as well as off the road ? Plz reply🙏
Question: Can a 2011 Mitz Endeavor awd be towed either with a tow bar or tow dolly, not a trailer, by disconnection the rear driveshaft or something? It has traction control/
i just acquired a 2013 Nissan Juke "S" model that is 2wd, unless i push the button on dash for AWD. Never used AWD yet, just plan to use Awd for snow. Right?
Hello guys, I have a very simple question that technicians from Skoda could not answer. I have 2015 Skoda Scout which has 4th generation haldex. The car has 32mm diference in width between the front and rear axles. As a result my rear bumpers look empty. Can I use wheel spacers at the rear axis to widen the track? Will this affect the haldex system? Regards
Can you explain different AWD systems used by different companies on sport cars or even exotics(aventador,R35)? How they manage to get a better acceleration since power is limited by traction?
I've got a more of a personal question. The Ultimate rally cars question. Wich do yo prefer subaru wrx/ wrx sti or the evo.. and more importantly why? what are the differences since as far as i know theyre both 4wd, 2lt, 4 cyl, turbocharged engines.
Hey, just to have a better understanding. What is crown gear center differential and how is that related to all of this such as transfer case. Im wondering because I saw a video simulation of the New Audi Quattro and was wondering if that is also what you are explaining.
ok i liked the video but i have a question for you if you can send it to me. Manual vs Auto if you can explain to me the pros and cons of both will be super. Tnx for the dreat vids
2wd utes have the 4H/4L settings 4L for max torque for hill climbing, 4H for low traction (but manual says not to use it much.) 2wd (rwd) for normal driving. (source: personal experience) awd like on a subaru is full time depending on the model forester gt which I have I believe is 50:50 for performance models like the wrx sti it is 41/59 then chances on corners, the situations I think. fill me in if you know the gaps :P
The graph seems wrong to me. The open central differential should be different from the wheel differential located on the wheel shaft, right? because one has got 2 rod connected and the other one has got 3 rod connected. If the central differential is like the one you draw, then the two shafts connected to them will rotate in opposite direction and no rotational difference will be allowed.
It's the same. Passat, Golf, A1, A3, Tiguan, Q3 and some others use this type of All Whel Drive. Cars like the Q5, Q7, A4 and so on, Macan, Cayenne, Phaeton, Touareg and in fact any VAG car with a longitudinal front engine have an LSD as the center differential.
not related to the video but can sombody explain the relation between catalytic converter and fuel economy of car? whether there is any effect of its removal on fuel economy? car has two o2 sensors pre and post CC. thanks
Lai Mun Wai AWD would have the best launch, but the most losses. RWD would probably do the best, as weigh transfers to the rear. FWD would likely have the least amount of power losses.
I would like to make my 4x4 1984 Sierra AWD. Would a viscous coupling and new driveshaft for the front axle meet the requirements or would more have to be done? Note the truck is for mostly road use.
The difference between 4WD and AWD has nothing to do with hi-lo gears. It's just Hi-Lo gears usually indicate a mecahinical 'link' between front and rear axles that defines '4WD'. AWD drive systems usually use some sort of viscous coupling to transmit torque between the axles.
hi there, in the auto awd situation would having the continuously spinning shaft spinning the clutch to rear axle increase rotating mass and detract from whp?
Do you have a video on different drivetrain layouts for AWD? Because I've been boggling my mind about how supercars manage to have a mid engine/ AWD setup (that and I have a tinker toy I wanna do the same to). Any help would be appreciable(:
So if my Buick Regal is FWD and I want to convert it to AWD is it worth it? I want to change the Turbo and get 600hp. So with that much Horse Power is it better to keep it FWD or should I get the 4WD conversion?
Quick question; I have a 2002 Mitsubishi Montero sport and along with the gear lever, there's a separate lever that has AWD, 4H, and 4L. For normal driving its left in AWD, but I've never really messed with the other two, but I'm assuming they're for four wheel drive hi and lo. Could u please explain how AWD and four wheel drive coexist in one set up in one vehicle? And how they set up would be configured? Thanks :) Btw love your vids, I legit wanna be an engineer after watching them :)
I have an 2007 hummer h2 and it is all wheel drive all the time. How can I make it be just 2 wheel drive when I want it to be? My old jeep Cherokee could switch back and forth. What needs to be changed in the hummer. Thanks for the help.
how can the open diff split power to the front and back. using your example if the front wheels were on ice and can only transmit 5 lbft of tq to the ground than the back wheels will only get 5 lbft of tq, and you're going to be stuck even if the multi plate diff or viscous coupling is locked up right ??
