@@Krystalmyth Don't get me wrong, I love Jason's channel too, just saying that he is professional, so, he makes what his costumers like, if they like a green board, he would use a green board, just saying about that.
@@Krystalmyth Observation: I already Said that I feel blessed for having this content (not on this commentary), so, In the "human side" the of the thing I feel like the friend of the commentary, just talking about business
I love this channel and I am so happy to see Jason’s success! I remember him doing videos in his uni bedroom and now he is using an M5 just to hold his whiteboard. Thank you for the content
Exactly! Keep 4WD for trucks and SUVs with an off-road bias and AWD should stay in cars. What BMW has done here is simply "over-engineer" the drivetrain for pure marketing and ability to charge more.
Outside BMW's marketing department, this is part-time AWD. It can vary power Front/Rear and that's the difference between AWD and 4WD. Just like you said in the beginning. The fact you can switch it from 2WD to AWD doesn't make it 4WD... just selectable AWD. It would be 4WD if the front and rear driveshafts turn at the same speeds, as with a normal transfer case, or locking center diff. That's how Land Rover gets away with calling their AWD SUVs "Full Time 4WD" they are AWD with a selectable locking center diff in the transfer case. No biggie, and you were spot on in the beginning, the variance of power Front/Rear is the determining factor. Love the videos and keep up the good work!
Told me exactly what I wanted to know. I was coming across a lot of usage-focused or "which is better" explanations to this question. But this video told me succinctly the gist of what the intrinsic mechanical differences between the two are. Thanks for that!
I really enjoy all of your videos for the technical detail you're able to provide in an easy to digest manner. However, as someone big into off road driving, rally or rock crawling, I get especially excited when you upload 4WD related videos. Thanks for all the great vids!
@@therealsnow well, that is a characteristic of a 4WD system anyway, which is probably why they chose to go with this system as it has all of the benefits of both 4WD and AWD. It's a really cool idea.
That's why they came up with a new name for their 4AWD (what ever you wanna call it lol) system. With their xdrive system, it's kind of like a smart AWD that dynamically changes how it sends power to each of the 4 wheels individually. So enthusiasts are coming up with a way of disabling AWD with an app, it's gonna be awesome!!
@@VictorEstrada yeah. That does sound awesome. It's a bit of a gimmick but it's another way to impress people when you show them your new M5. As if the power and speed aren't enough!
That was a good simple explanation of AWD and 4WD. The problem people have is not KNOWING when or where to use 4WD in a traditional setup. That is why you see so many SUVs that are 4WD in ditches or on their sides in BAD weather conditions. 4WD locks the front and rear together and can not regulate any change in wheel speed, so when you turn the wheel even slightly the system binds and you get into a situation where you can easily loose control of the vehicle. You do not need 4WD to drive on snow, it is worthless on ice due to the binding and is only recommended for low speed use. Off road racing has 4WD, but is very rarely used due to the speeds driven. As for the system being used by BMW in the M5, it isn't true 4WD. It is fantastic engineering. The use of the clutch pack inside the transfer case is smart. Allowing for variations in wheel speed and knowing the wheels are not slipping is great engineering. I look forward to seeing this type of transfer case being used on SUVs and full size pickups. It would save insurance companies and drivers a lot of money. Now do a video explaining how 4WD is ACTUALLY 2WD, and maybe explaining the ORIGINAL TRUE 4WD SYSTEM that allowed for wheel speed variables and did not bind. It came out in the 70s, build and ONLY used in JEEP when it was JEEP/AMC. Well before Chrysler bought Jeep. The name is QUADRATRAK. All time, high speed 4WD. You had a small lever in the floor that switched from HIGH to LOW range 4WD. The system had a switch/knob in the glove box in case you ever ACTUALLY stuck the JEEP. The owner's manual told you to put the floor lever in LOW, put the transmission in lowest gear, then turn the knob to ON. DO NOT TOUCH FUEL PEDAL. Sit back and wait until the vehicle climbed out of whatever you were stuck in. I had this on a 78 CJ7. This system was WAY AHEAD of its time.
I just spotted this one, and watched it. Good video, and a good attempt to explain the difference between AWD and 4WD. However, several things you said are not quite true" First , no matter what BMW "claims" their X-drive system is, it is, in reality, a selectable AWD system, not a 4wd system. The presence of that clutch pack in the transfer case really turns it into an AWD system when turned on. It's all about marketing really. Second, a 4wd system can absolutely be used on the road in 4H or 4WD without the gearing reduction. There are two great uses for this, snow and rain conditions. On dry pavement, it will still work just find and the amount of bind in the center in minimal. So if you're driving on a paved road with some snow cover, you can use 4H without endangering your driveline, with no need to keep switching the t-case from 2H to 4H and back. $L is for offroad use because it WILL create a lot of bind in the drivetrain if driven on the street. But again, in deep snow it will also work fine. Third, AWD is NOT good for offroad. It actually sucks. Mostly because AWD systems do not have the strength in the driveline components to take on rocks and other high-stress obstacles without snapping. Also, AWD systems often use a vscuous coupling unit for that center differential, which when stressed very hard (as offroad obstacles are wont to do) the coupling unit will slip and overheat the oil in it, possible burning it out. Lastly, AWD systems are not mostly FWD and then they send torque to the rear when needed. Some do that, mostly care that in their non AWD version is a front drive car. If the base model of the AWD car is a RWD car, then usually the AWD version is heavily rear biased AWD. Some thing like a 35:65 torque split (which was the normal split for the Astro Safari minivan's AWD versions). Check out Subaru's AWD system in the Outbacks. Most AWD systems are not one axle gets all the torque until needed, but they have a preset bias. 85:15 is common for cars that are FWD base models. Basically AWD is a street system that provides excellent traction in wet/snowy conditions and great off-the line starts without wheelspin, and 4WD is for offroad performance. Keep up the good videos though, your content is easy to watch and fun.
You took the words right out of my mouth. Except I would say that this video spreads bad information. As you said... 4WD is fine on the road. Modern 4WD systems don't get the binding that he claims.
The 4WD systems that bind are a lot better offroad, as they act like locked diffs. I muuuuuuuch prefer them. I want front, center, and rear locked. Maybe be able to turn the front off, but meh. For example, my 2001 pathfinder could not be driven on road unless there was slip, like wet leaves or ice. And it was a beast offroad. My 2012 Xterra has some slip in the transfer case and open diffs, so it can be driven on road in 4WD mode. However, offroad it has the capabilities of a coma patient on a skateboard. All AWD systems suck offroad.
@@spraynpray Not so fast. My 96 zj has full time awd. It does have a 4 low but I've only put in a few times just to make sure it engages. With a solid 8.5 inches of ground clearance and 30 inch AT tires she does great both on / off road and in the snow.. in just awd.
My aunt had an awd suv that struggled to get through the driveway when it snowed, because you couldn’t set/select when all the wheels engaged. They would only all engage after the tires started spinning, which made it useless at that point anyways. Since then she’s gotten a select 4wd suv and has no problem.
Jeep did this nearly 20 years ago with a viscous coupling in the transfer case. And my 89 cherokee can be set in 4wd full time which basically makes the tcase an open diff, as well as locked and low range capabilities.
Jason, Never give up the whiteboard. It's just such a part of the channel's charm. It also gives a really unique vibe to the channel. Reviewing high end cars on a white board. Love it.
I used to have an ‘88 325iX and it used a viscous coupled transfer case. It was completely seamless and its intelligence was in the elegant simplicity of the design. You didn’t need multiple clutch plates or speed sensors, it just used the natural property of the oil to thicken up when there was slippage.
If I remember right, the viscous coupling means that you sometimes have to change the oil, right ? Like if you practice a lot of off-roading, if the diff gets hot, the oil can literrally turn to pee and the shear effects inside the coupler get weak ?
@@fridaycaliforniaa236 Yeah just drain it and fill it back up with gear oil. It’s as easy as changing engine oil, or even easier since there’s no filter. Just like a diff
My first encounter with AWD was in my '86 VW Syncro Wagon. Default was AWD but there were two vacuum controlled differential locks. I remember only using the locks experimentally a couple of times. I only needed to lock both in one instance. That was to drive out of a very deep snow bank. The car was a gasoline hog, but I loved it in the winter.
You are not correct on this one. AWD and 4WD are the same thing. The actual terms used for what you're explaining are "Full-time" and "Part-time". A full-time AWD/4WD system is always engaged, powering all the wheels, with a central diff (it could be a simple open diff or a diff with an additional automatic locking mechanism). Some such systems come with a user lockable central diff, like Land Rover Defender and Toyota Land Cruiser; some don't, like a lot of AWD/4WD passenger cars and crossovers. Part-time systems can be engaged and disengaged by the driver, and don't have a central diff. They are usually meant to be driven in 2WD mode on normal roads and the 4WD mode is intended for loose terrains like mud, snow, sand, etc. Examples are the Jeep Wrangler, Toyota Tundra and Hilux. There are part-time vehicles like the BMW shown in the video that can always be driven in 4WD mode but such solutions are not present on all part-time systems. These systems use some sort of an automatic locking mechanism, which could be a clutch, a viscous coupling, etc.
The reason I bothered opening the video was I figured the whiteboard too simple for this one and wanted to gripe. I've got an AWD system that looks identical to the 4x4 setup on the whiteboard.
Thanks for explaining the part time and full time bit. You made me understand that my 2007 toyota auris with 4wd is actually part time. There is a button i press to disengage 4wd when im driving regularly. On sandy, wet and rough areas i engage it and the tires 'grip' the road better.
@@randrews25 Does the button you mentioned have the word "Auto" written on it? I'm not completely familiar with that car's 4WD system, but based on what I've read you should be able to use the 4WD mode all the time. The system sends power only to the front wheels most of the time but when necessary, it will also send power to the rear wheels. Check the user manual to make sure. IINM It is an automatic part-time system, pretty similar to the one in the video.
I think he has, across different videos, described electronic, various mechanical, and open differentials as well as active torque vectoring, the most common name or at least what I call combining open differentials with brakes to "vector" the torque away from a slipping wheel by immobilizing it. Each AWD system is a combination of these differentials that can (think disconnecting axles) have all wheels connected to one or more engines.
THANK YOU FOR ANSWERING THIS, this is kinda what i thought, lack of a center differential, but it was NEVER clear anywhere i looked this discussion has come up so many times for me and i never had an absolutely certain answer for anyone
I drive a Hummer H2 and I honestly don’t have a clue how the 4wd system works. It’s supposed to be all wheel drive all the time and then when you need to you can put it in 4wd and lock the front and rear differential. I’d really love to see a video explanation on how the whole system works together if you think that would be a good idea for a video. Love the content!
Didn't you have a video covering all wheel drive in the 911? You should put that one up there in the description too since that's a bit different with the engine in the rear.(I think you mentioned how it's effectively a rear wheel AWD system that sends power to the front vs most systems which are effectively front wheel that can send power to the rear.)
This guy has top-list infos! I’d started to watch his vídeos since his 500k or so subscribers. Now he got +2,3mi and demonstrates the same motivation to spread his knowledge. Thank you for sharing...👍. Congrats, from Brazil!😉🍾
BMW GB are right - we Brits use the terms 4WD and AWD interchangeably, assuming the vehicle has four wheels, of course. We also find it weird that Americans call just the gearbox the transmission, whereas we call anything from the clutch or torque converter to the driveshafts the transmission.
Where I live most people just say four wheel drive. Trying to differentiate AWD from 4WD when there's not really a clear cut line between what is what anymore only brings confusion.
Interestingly, AMC Jeep made an all wheel drive, full-time Four wheel drive system back in 1973. It was called Quadra-Trac. I had one for 30 years. Does what AWD does, but then you can lock up the transfer case and for off road or when things get really shitty. it also has low range and neutral for towing. A fantastic system.
One of the problems with computer controlled AWD is that the power transfer can get flaky in conditions not programmed for. I have seen units nearly cause loss of control in a windy mountain road. Nice explanation. Thanks.
@@danhill6176I would assume just certain cars. I have a Subaru and my AWD is phenomenal. I've taken it on dirt at triple digits speeds, drifted in snow and ice, never had any issues.
Easy Explanation for these drive-trains: All-Wheel Drive = works on *ALL* drive-able surfaces~ 4-Wheel Drive = works when *4* wheels need torque at the same time~ Also FYI @4:29, Audi created a AWD drive-train design like this BEFORE BMW did. My 1987 Audi 5000 CS Quattro has a dial selector that lets the driver switch where the engine torque is being distributed: selections are front axle, rear axle, or both axles.
Daniel B The X5 now has Air suspension and a intelligent AWD system and the car has modes for snow, sand and all that kind of stuff almost 9 inches of ground clearance and the M5 will need to loose it’s bumpers and side skirts in order to go off roading even with a lift do to the sporty nature of the design
Yes my Sequoia does this. I have 2WD, 4HI (unlocked), 4LO (unlocked), 4HI (locked), 4LO (locked). When the transfer case is in 4WD unlocked then its running through a TORSEN center diff so you get some torque bias to the wheels with traction.
Jeep Cherokees and grand cherokees had this as an optional transfer case. They had 2-hi, 4-hi(part time) 4-hi(full time) neutral and then 4-lo as options to select when driving.
Great video def watch through full vid everyone. I love the technical and data based take you have man. Actual quality content!!! AWD - Automatically handled by car's system and distributes power to where it's needed. Works on road and off road. 4WD - Manual, better off road.
Yes and no. The car removes the need for the driver to choose which wheels drive and when. The driver cannot even make the choice to go into 4wd (at least not in the Ford Kuga we have). It will usually run in 2wd, but when it senses the need to direct some of the power to the rear wheels, it will do it quickly. For those of us who prefer to have control over the drive and axles used, a 4wd is the way to go.
My old Subaru had a fuse for towing that would disengage the center diff. It wasn't "selectable" unless you wired in a trivial switch. :D I ran it as FWD every summer for a half dozen years and saved 2-3MPG. Now, my old Chevy truck has a hoist pully for engaging the Hi or Low 4WD. I have to shift into Neutral for the Low to engage and it makes quite a "clunk" when it does so. My current Honda calls itself 4WD but there's no clunk and even its diff-lock mode "VTM-4" can be engaged in 1st gear. Nice, but "lockable AWD" in my book.
The Nissan R32 GTR in the early 1990s had that exact 4WD system as that BMW (ATESSA). It has a clutch pack in the centre pressurised by a hydraulic pump. The car stayed in rear wheel drive until certain parameters were true (slip angle, yaw, steering angle etc), then it would transfer up to 50% to the front. Probably why it dominated in racing! Every GTR after that has an evolution of the ATESSA system.
Don't really understand why BMW had to reinvent the wheel here. The E63S managed a RWD only mode with AWD. And you said it, AWD is better in the corners. Nevertheless it's nice tech.
Good video. I will throw my two cents into the cup. I will use a rear 4x4 drive vehicle as an example. One rear wheel provides the power. When the 4x4 lever is pulled, the opposite front wheel then also has power. Not for driving on dry roads, and turning will bind. Like my former 1999 Pathfinder. An exception is a vehicle with locking front and rear differentials. Both rear wheels have power. When the 4x4 lever is pulled, then both front wheels also have power. Not for driving on dry roads, and turning will bind. Like my former 1995 Pathfinder. My dearly departed beloved 2002 Subaru Outback wagon with a manual transmission had All-Wheel drive. All wheels had power all the time. One problem with that set-up is the tires all have to be the same circumference. The previous owner of this car replaced one bad tire instead of all of them. It had a larger circumference than the three worn tires. I bought the car not knowing either of these facts and had to replace the transmission. The clutch was worn, anyway. Could be the automotive engineers have changed all this and never bothered to tell me.
Great Video. This is an explanation of part-time 4WD, but doesn't cover "permanent", "constant" or "Full-time" 4WD. Now, I hold the opinion that AWD is just permanent 4WD, like a Subaru for instance. AWD is simply a marketing term. In the Subaru's case, it has a viscous coupling system which carries out the same function as a multiplate clutch pack system or a centre differential. Some permanent 4WDs can select to lock the Centre Differential, thus changing from Full-time 4WD, to "True 4WD". (yes, I'm aware that front and rear axle lockers are technically required to induce "True 4WD"). I feel the difference is that the Centre Differential can be manually locked via a selection made by the driver, whereas the AWD system cannot.
Easy, all wheel drive is when all of the wheels receive power from the transmission. Four wheel drive refers to when only 4 wheels receive power. Now give me an Engineering degree!
@@EngineeringExplained Hey Jason, during the drive to university today I stumbled across a ~2010ish Mercedes C225 which had the 6.3 AMG badge on it (obviously fake) which got me thinking; is it better to have larger cylinders or more cylinders if you could choose one. Thanks, keep up the great work!
I have an AWD Ford Edge. Years ago, I had a Ford F150 4x4. One thing I learned....AWD-4X4, it ALL really depends on weather conditions. Both perform poorly on icy covered roads but, in my experience perform about the same in deep snow conditions. Only thing the 4X4 is 100% better at, is for helping to tow another vehicle.
Love tour videos. the difference is some 7,000-10,000 USD worth of repairs when these Magna Steir manufactured AWD start failing. Some had 3 units by 100,000 kms. F3x and X3s X5 2011-2018 are losing them so fast that there is a long wait for one. Am on the 6th month of this AWD transfer case, the new one having arrived from Germany early aug 2021, but WITH THE INCORRECT FLANGE for an F30! of course the front driveshaft was found out of balance due to some insulator foam that rubbed for who knows how long. New transfer cases shot up from 900$ USD to 5,000 USD for a 2021 revision. All and all, it started shy of year 6 and end of warranty but BMW could not find the source of the tiny vibration. TC failed march-april 2021. Remanufactured one was also defective. New one ended up 7,500$ CAD plus reprogramming plus a new driveshaft, all dine at an independent sports car garage that loaded me with discounts. total cost of fixing this on my 2014 M Performance is 8,000$ USD.... yes these transfer cases are badly designed and built for the torque and heat that we have these days. original one was fiund with seized bearings, and the whirrrrrrrrr, very very faint, kicked off 2019, car at 70,000 kms... so did vibrations in very rare condition (high speed turn ramp to the right)... anyways, if you can drive a RWD with winters, do so!
Just an FYI... that BMW transfer case is likely made by Magna. Magna makes Cfer cases for 60% of 4wd vehicles on the road. GM, BMW, Jeep, and many others use one of their variants. Also, many Xfer cases these days have an Ultimate Combo that was not mentioned! My Chevy Colorado has 2wd, Auto, 4Hi, AND 4Low (And neutral mode for towing behind an RV). With “Auto” mode the center diff is unlocked like an AWD system so you can drive around on patchy dry pavement and not bind the drive train. 4HI and 4LOW locks that center diff. Enabling 100% of the power to be sent to any single tire instantly when off road(with locking diffs front and rear). As long as a single tire has traction. You won’t get stuck.
I noticed 2 weeks ago that the current gen CRV use AWD while the previous gens were using 4WD and yet, it's still the same system?! I guess they changed it for marketing?!
I have the 2002 Honda CRV and it is AWD but it's a little different than Jason explained. The car is always in Front wheel drive and power is always available to the rear axel but each rear wheel has it's own wet clutch system in the rear axel. The rear wheel axel clutches engage only when there is torque applied. So steady state road speed the are off, braking and coasting they are off but when you hit the gas pedal from a dead start there is enough of a torque load there to engage the rear wheel drive clutches. It works pretty good and can send some gravel or snow out behind you. It's taken me up steep snowy roads that front wheel drive cars struggled on. Having the rear disengage when the torque goes down saves gas. The new models are just the same.
Yeah the CRV is a reactive system, just like my Suzuki SX4 was. I don't like that, sometimes it reacts too late. I prefer by far how my Crosstrek works, I just wish it could have a turbo offered. :)
@@groovymotion5706 My CRV has no reaction lag at all. I can toss the rear end around in the snow just like a rear WD. Got to do that today too. It's a fun little SUV IMHO. I've got over 220,000 miles on it and the only significant problem was loosing the air conditioning compressor at around 170,000 miles. The Crosstrek looks like a great car. I might try that next!
@@mikeh2520 Yeah but it's still a reactive system. The SX4 was great for drifting but terrible for fuel economy! Yeah the CRV look extremely reliable! As for the Crosstrek, it's great for having 2 wheels on lots of snow and the others without, there is no torque steer. Only bummers are the terrible lack of HP and the fact that you can't totally disable the ESP...there is a way but just for below 50kmh.
There is none, an AWD car can accommodate different wheel diameters as it has 3 differentials (Or other devices allowing wheels to go at different speeds like Fords replacing of the center and rear differential with 2 clutches, one to send drive to each rear wheel).
If the tires are different diameters, the differentials etc will need to compensate, and thus will heat up and wear faster. Usually you would replace 2 tires
Be careful if you ever tow any AWD vehicle. Never tow with only 2 wheels on a dolly. The speed difference at the center diff will be so great that it will blow itself apart. Some vehicles have front or rear axle disconnect for this purpose.
@@peglor That is actually incorrect. Just about all awd systems include a disclaimer that all tires and wheels need to be the same size and type or damage will occur. At most they were designed to accomdate the use of a manufacturer spare tire for a temporary period of time.
Interesting... in light of the different set-ups by manufactures: I asked a dealer mechanic/tech about my vehicle (AWD) and if it is always using all wheels or if it is automatically selective. His answer was that two wheels move the vehicle (saving fuel) until slipping is detected, then power is transferred to the gripping tires, whether it be two or three wheels as needed until traction stability is regained. In essence, mine acts like a 4WD automatic system. I thought that's was pretty cool not to share. Of course some vehicles use all four wheels all the time.
All wheel drive is when all 4 tires spin all the time at diffent speeds 4wheel drive is when you can have 2 or 4 wheels Spin at the same same speed all the time
Yes, because there is no clear definition for both. If you want all wheels possible to be driven you have to check how they are linked. That's it. Don't use marketing therms, just use engineering stuff and compare them before choosing a car.
My 2005 Ford Escape was a full time 4WD, or four wheel drive car. I enjoyed everything about it except feeding it fuel, That beast was thirsty. My 1015 F-150 is 4X4, or Four Wheel Drive but I do have a 4A setting , 4 Automatic, which runs like all wheel drive.
Great video as always, but I disagree. There are too many different mechanical systems for just two terms. I do understand the colloquial differences between 4WD and AWD, but I have yet to see a consistent mechanical difference between them. The sole exception is that a system that has a low range is not called AWD, although there might be an exception to this too. I view 4WD and AWD as technically and mechanically synonymous, with people generally using 4WD for trucks and SUVs and AWD for SUVs and cars.
There's definitely not as much of a difference between the two categories in newer vehicles than traditionally since car companies incorporating AWD features in 4×4 systems and vice-versa.
This was a very complicated way of saying one is permanment 4 wheel drive or manual selectable; the other is just auto selectable as needed, with AWD another wheel can be switched on and off in a fraction of a second; the car's mode control will set parameters for how quickly and in what proportion so is actually considerably better. For BMW drivers it doesn't matter people have only bought the badge, for American cars it doesn't matter because everyone lives in Hazard county and drives a Charger :)
So basically 4wd is the more primitive system where all wheels receive identical power at all times (unless it’s set to 2wd ofc), whereas awd is a “smart” variation of 4wd that’s adjusts power being delivered to each individual wheel as needed. Is this correct?
It is worth pointing out that in the UK, they do legitimately use 4x4, 4WD, and AWD interchangeably, even in cases where the hardware is distinctly different. I'm guessing this is mostly because for them, legit 4WD vehicles aren't all that popular, let alone necessary for most of their population. It's kind of like Americans and the word "liberal", which basically became synonymous with socioeconomic leftist ideals, even though the actual definition is actually somewhat contradictory to that.
I think it probably a marketing thing, non car people will not care either way, but if four wheel drive sounds cooler in their simple minds then it might sell better.
@@acarguy3773that is true, but in german there has never been a distinction between the words, they were always used interchangably even by experts. Or maybe a better explanation of what i mean: awd or 4wd or 4x4 were never locked to a working principle in german. The distinction (if it was made at all), was made by adding the working principle to one of the epressions: "permanent, zuschaltbar, haldex, visco etc.") Nowadays of the 3 only "Allrad" seems to have survived in german.
@@nirfz aahh interesting. Maybe that is one of the reasons for all of the confusion then, even in English. I never knew any of that. I suppose it makes sense to do it that way though, and it gets rid of any ambiguity if they specifically say what type of system it is.
Mitsubishi Montero/Pajero has severals options of traction. It has a transfer case but also has a central diff. So it allows to select 2H, 4H, 4HLC, N, 4LLC. 2 Wheels drive, 4 wd with open central diff for using on tarmac, 4 wd with locked central diff for snow, gravel, sand... neutral, and 4 wd central diff locked and low range for maximun torque and low speed. It's quite reliable and I think is the most complete traction system since 90's.
@@nizm0man That is AWD, user selectable full time 50/50 front to rear bias is the common definition of 4WD used by everyone but europe apparently. All Wheel Drive is defined as any form of automatically variable and/or non-50/50 front to rear bias. At least that's the definition Japanese, American and Australian auto manufacturers have stuck to and the definition any layman in those countries would try to describe.
I was thinkikg about that too cuz if you search subaru imprezas for sale in nettiauto some say awd some say 4wd makes me confused asf that thise gc8 has 4wd and new ones awd
The AMC Eagle was an automatic all wheel drive. They were actually were fun to drive. The first ones were completely automatic, later models were selected drive with a selector switch. The 1980 model was the most fun, in my opinion.
I've seen videos trying to explain the difference in a purely mechanical sense, and they just left me confused. This video explains it in a mechanical and a practical sense, so now I have more of an understanding.
i always thought the difference is just wheter it is permanent or not. after this, the haldex system (golf) would be an 4WD system, but after this, it would be a AWD system, because it has a differential. And the system also distributes the power itself (but just when there is slip in the front as far as i know)
I don't think there's any real accepted definition. Centre diff is no good as a differentiator because many AWD systems don't use centre diffs - Subaru's automatic cars these days use a wet clutch pack that basically clamps the rear drivetrain onto the front drivetrain with a varying degree of grip so as to allow the rear to slip to rotate at a different speed. Many other AWD systems do this too, I'm pretty sure that any on demand system will because that would make the most sense for a system that's designed to only drive the rear (or rarely the front) in specific relatively uncommon situations. Meanwhile you have 4WD systems that do use centre diffs - the LandCruiser uses a transfer case that instead of working like a traditional 4WD system is actually a low range gearset and a torsen limited slip diff with a diff locker on it to enable full locking. The G Wagen also uses a locking centre diff - no idea if it's limited slip when not completely locked though. You could use the selectable function to differentiate but then you get grey areas with AWD cars that can have their operation driver controlled to an extent, like the Focus RS and the WRX STi, not to mention that full time 4WDs like the LandCruiser will happily work as a very good AWD vehicle even if the driver never touches low range or the locker. Maybe mechanically selectable? Really I think low range is probably the best differentiator because that seems to be the biggest limitation on how much AWD cars can do these days with increasingly sophisticated traction control.
The M5 F90 is actually 4WD which is quite quirky on a sports sedan So if I want to go drifting, I can just switch to RWD which is so much better than drift mode
An ideal system has three Torsen differentials, one in the center and one for each axle. However, the problem here is the cost. So most manufacturers use one Torsen for the center and then traction control on each axle/tire.
The Pajero offers the same thing. It has a 4WD mode and a 4WDHLc Mode which locks the center diff while in 4wd mode. The Evo also has 4WD with the ACD acting similarly to a locked center diff in "snow mode"
I'm not convinced he's right on this one. I think, as BMW state, 4WD and AWD are just marketing terms with no real definitions. The term does not imply any particular design of centre diff.
My thought exactly. This just seems to be a marketing term for manufacturers like Toyota that build both on- and off-road cars to state that the 4WD system is completely different between the two. Which is likely to be true but is in fact the result of other components like being to able to lock the differential and select low gearing. Which given the ground clearance of this BMW you are very unlikely to find in there.
As far as I know, in german we don't use different words for the different systems. They are all called "Allradantrieb" - all wheel drive. Maybe that's why BMW states "it's all the same".
Excellent description. AWD = center diff, 4WD = transfer case. As someone who has owned 4WD vehicles, and was familiar with the transfer case, I wasn't sure how an AWD differed. Thank you.
Professional TH-camr and still uses whiteboards for graphics, I love it! Keep things real man!
He saves them. He filled his basement and is working on the attic.
It doesn't makes senses thanking him for it. He is professional, he has customers, he do what customers want him to do and earn his money.
@@luizhenriquepaes8991 You just said it doesn't make sense to thank someone for something they appreciate. Your parents failed you, and society.
@@Krystalmyth
Don't get me wrong, I love Jason's channel too, just saying that he is professional, so, he makes what his costumers like, if they like a green board, he would use a green board, just saying about that.
@@Krystalmyth
Observation: I already Said that I feel blessed for having this content (not on this commentary), so, In the "human side" the of the thing I feel like the friend of the commentary, just talking about business
The spare tire also spins with AWD, simple as that :)
That's why Subaru keeps the spare hidden!
😂
Makes sense, acts as a reaction wheel to give the car better stability. :D
Its like a gyroscope to help it to stay stable
😂😂😂
I love this channel and I am so happy to see Jason’s success! I remember him doing videos in his uni bedroom and now he is using an M5 just to hold his whiteboard. Thank you for the content
Hahaha, M5 as a whiteboard stand = success!! 😂😂
Engineering Explained what’s next, a 911 as a coffee table?
Well, to be fair, that's all its really good for
@@AnArmoredMarch Totally, bro... Gawd damn useless pesky M5s!!
Indeed,he's whiteboard stand getting bigger & expensive
Average engineer: "Simply use AWD for road car and 4WD for offroad car."
German engineer: "How about making 4WD more complicated so it can mimic AWD?"
You forgot the “ let’s charge them an arm and a leg for it”
Yes, and yes what Troy said xDD
Yeah, it's great until it breaks :)
Germans over engineer everything.But they do make some great machines. That you can never deny.
Exactly! Keep 4WD for trucks and SUVs with an off-road bias and AWD should stay in cars. What BMW has done here is simply "over-engineer" the drivetrain for pure marketing and ability to charge more.
Finally I can go rock climbing in my M5!
🤔
ummm..... lol
I don't think that means what you think that means!
if you buy some truck tires to increase the space beneath you and the ground it would be possible - like most things :D
... on the m5, in cruise control ;)
This whiteboard stand must have been expensive
Buying an M5 was a poor investment on my part, simply to hold up a whiteboard! 😂 (Thank goodness for press cars).
Lol
Should’ve just just used the door of the m5
@@michaelrossi3707 might be difficult to get hold of future press cars if your are seen doodling on them
@@michaelrossi3707 At 0:07 you can see the result of all the failed takes when recording this ;)
Outside BMW's marketing department, this is part-time AWD.
It can vary power Front/Rear and that's the difference between AWD and 4WD.
Just like you said in the beginning.
The fact you can switch it from 2WD to AWD doesn't make it 4WD... just selectable AWD.
It would be 4WD if the front and rear driveshafts turn at the same speeds, as with a normal transfer case, or locking center diff.
That's how Land Rover gets away with calling their AWD SUVs "Full Time 4WD" they are AWD with a selectable locking center diff in the transfer case.
No biggie, and you were spot on in the beginning, the variance of power Front/Rear is the determining factor.
Love the videos and keep up the good work!
Told me exactly what I wanted to know. I was coming across a lot of usage-focused or "which is better" explanations to this question. But this video told me succinctly the gist of what the intrinsic mechanical differences between the two are. Thanks for that!
I really enjoy all of your videos for the technical detail you're able to provide in an easy to digest manner. However, as someone big into off road driving, rally or rock crawling, I get especially excited when you upload 4WD related videos. Thanks for all the great vids!
Happy to hear it, thanks for watching!
So the M5 has 4WD that mimics AWD? Clever!
But with the ability to go rear wheel only drive if desired, nice idea :)
@@therealsnow well, that is a characteristic of a 4WD system anyway, which is probably why they chose to go with this system as it has all of the benefits of both 4WD and AWD. It's a really cool idea.
@@therealsnow some new amgs can do that aswell, even thou they are awd
That's why they came up with a new name for their 4AWD (what ever you wanna call it lol) system. With their xdrive system, it's kind of like a smart AWD that dynamically changes how it sends power to each of the 4 wheels individually. So enthusiasts are coming up with a way of disabling AWD with an app, it's gonna be awesome!!
@@VictorEstrada yeah. That does sound awesome. It's a bit of a gimmick but it's another way to impress people when you show them your new M5. As if the power and speed aren't enough!
I'm a simple guy. I see a whiteboard, I press like.
Good job dude who disliked it
U
Ok
Had to like your comment to get it to 666! I also appreciate the simple things in life, such as whiteboards. :)
@@bryanmoreno2433 Whiteboard racist
That was a good simple explanation of AWD and 4WD.
The problem people have is not KNOWING when or where to use 4WD in a traditional setup. That is why you see so many SUVs that are 4WD in ditches or on their sides in BAD weather conditions.
4WD locks the front and rear together and can not regulate any change in wheel speed, so when you turn the wheel even slightly the system binds and you get into a situation where you can easily loose control of the vehicle.
You do not need 4WD to drive on snow, it is worthless on ice due to the binding and is only recommended for low speed use.
Off road racing has 4WD, but is very rarely used due to the speeds driven.
As for the system being used by BMW in the M5, it isn't true 4WD. It is fantastic engineering. The use of the clutch pack inside the transfer case is smart. Allowing for variations in wheel speed and knowing the wheels are not slipping is great engineering.
I look forward to seeing this type of transfer case being used on SUVs and full size pickups. It would save insurance companies and drivers a lot of money.
Now do a video explaining how 4WD is ACTUALLY 2WD, and maybe explaining the ORIGINAL TRUE 4WD SYSTEM that allowed for wheel speed variables and did not bind. It came out in the 70s, build and ONLY used in JEEP when it was JEEP/AMC. Well before Chrysler bought Jeep. The name is QUADRATRAK.
All time, high speed 4WD. You had a small lever in the floor that switched from HIGH to LOW range 4WD. The system had a switch/knob in the glove box in case you ever ACTUALLY stuck the JEEP. The owner's manual told you to put the floor lever in LOW, put the transmission in lowest gear, then turn the knob to ON. DO NOT TOUCH FUEL PEDAL. Sit back and wait until the vehicle climbed out of whatever you were stuck in.
I had this on a 78 CJ7. This system was WAY AHEAD of its time.
I just spotted this one, and watched it. Good video, and a good attempt to explain the difference between AWD and 4WD. However, several things you said are not quite true"
First , no matter what BMW "claims" their X-drive system is, it is, in reality, a selectable AWD system, not a 4wd system. The presence of that clutch pack in the transfer case really turns it into an AWD system when turned on. It's all about marketing really.
Second, a 4wd system can absolutely be used on the road in 4H or 4WD without the gearing reduction. There are two great uses for this, snow and rain conditions. On dry pavement, it will still work just find and the amount of bind in the center in minimal. So if you're driving on a paved road with some snow cover, you can use 4H without endangering your driveline, with no need to keep switching the t-case from 2H to 4H and back. $L is for offroad use because it WILL create a lot of bind in the drivetrain if driven on the street. But again, in deep snow it will also work fine.
Third, AWD is NOT good for offroad. It actually sucks. Mostly because AWD systems do not have the strength in the driveline components to take on rocks and other high-stress obstacles without snapping. Also, AWD systems often use a vscuous coupling unit for that center differential, which when stressed very hard (as offroad obstacles are wont to do) the coupling unit will slip and overheat the oil in it, possible burning it out.
Lastly, AWD systems are not mostly FWD and then they send torque to the rear when needed. Some do that, mostly care that in their non AWD version is a front drive car. If the base model of the AWD car is a RWD car, then usually the AWD version is heavily rear biased AWD. Some thing like a 35:65 torque split (which was the normal split for the Astro Safari minivan's AWD versions). Check out Subaru's AWD system in the Outbacks. Most AWD systems are not one axle gets all the torque until needed, but they have a preset bias. 85:15 is common for cars that are FWD base models.
Basically AWD is a street system that provides excellent traction in wet/snowy conditions and great off-the line starts without wheelspin, and 4WD is for offroad performance. Keep up the good videos though, your content is easy to watch and fun.
Thank you, this video made me paranoid that I may be damaging my jeep by using 4H on snowy/icy roads, glad to hear it's ok!
@@luchts4547 same thinking until I got to this comment. I always believed what Bill said, but the video had me paranoid.
You took the words right out of my mouth. Except I would say that this video spreads bad information. As you said... 4WD is fine on the road. Modern 4WD systems don't get the binding that he claims.
The 4WD systems that bind are a lot better offroad, as they act like locked diffs. I muuuuuuuch prefer them. I want front, center, and rear locked. Maybe be able to turn the front off, but meh. For example, my 2001 pathfinder could not be driven on road unless there was slip, like wet leaves or ice. And it was a beast offroad. My 2012 Xterra has some slip in the transfer case and open diffs, so it can be driven on road in 4WD mode. However, offroad it has the capabilities of a coma patient on a skateboard.
All AWD systems suck offroad.
@@spraynpray Not so fast. My 96 zj has full time awd. It does have a 4 low but I've only put in a few times just to make sure it engages. With a solid 8.5 inches of ground clearance and 30 inch AT tires she does great both on / off road and in the snow.. in just awd.
Simplicity with using white board makes your explanations simple and clear for viewers
Thanks a lot...
My aunt had an awd suv that struggled to get through the driveway when it snowed, because you couldn’t set/select when all the wheels engaged. They would only all engage after the tires started spinning, which made it useless at that point anyways. Since then she’s gotten a select 4wd suv and has no problem.
I drive a honda chipmunk with a garden shovel, wrecking bar, 3 iron pipes, and an aluminum baseball bat. Snow is not a problem for me.
@@Lee90000 man’s gotta work to get out of snow😂
Jeep did this nearly 20 years ago with a viscous coupling in the transfer case. And my 89 cherokee can be set in 4wd full time which basically makes the tcase an open diff, as well as locked and low range capabilities.
Jason the type of guy I can depend on to upload on a Sunday.
Jason,
Never give up the whiteboard. It's just such a part of the channel's charm. It also gives a really unique vibe to the channel. Reviewing high end cars on a white board. Love it.
It's going no where! Glad you enjoy it haha, thanks!
I used to have an ‘88 325iX and it used a viscous coupled transfer case. It was completely seamless and its intelligence was in the elegant simplicity of the design. You didn’t need multiple clutch plates or speed sensors, it just used the natural property of the oil to thicken up when there was slippage.
If I remember right, the viscous coupling means that you sometimes have to change the oil, right ? Like if you practice a lot of off-roading, if the diff gets hot, the oil can literrally turn to pee and the shear effects inside the coupler get weak ?
@@fridaycaliforniaa236 Yeah just drain it and fill it back up with gear oil. It’s as easy as changing engine oil, or even easier since there’s no filter. Just like a diff
They might as well make it so the suspension can raise a couple inches or feet so your bmw m5 can be an off road tank
Looks like BMW just reinvented the AMC Eagle
@@angelocardoc if you ever drive a first Gen x5 they drive exactly like you'd expect a lifted e39 to. No crossover fluff
*Dude it's easy 4WD uses 4 wheels and AWD uses all the wheels* 😂😂😂
Which in a car with 4 wheels can mean the same thing. 😒 So you need to be specific.
Abhilash Nair Think...humour!!
@@recommit Uh yeah. 😅😂
Then let me create the impossible: A Peel P50 with 4WD!
_Bob McCoy so FWD means four wheel drive? True story though, I went to look at a used car and the guy told me it’s 4wd coz it says FWD lol!
My first encounter with AWD was in my '86 VW Syncro Wagon. Default was AWD but there were two vacuum controlled differential locks. I remember only using the locks experimentally a couple of times. I only needed to lock both in one instance. That was to drive out of a very deep snow bank. The car was a gasoline hog, but I loved it in the winter.
I have vw t3 synchro diesel. Is the best 🚛 on snow and off road
You are not correct on this one. AWD and 4WD are the same thing. The actual terms used for what you're explaining are "Full-time" and "Part-time".
A full-time AWD/4WD system is always engaged, powering all the wheels, with a central diff (it could be a simple open diff or a diff with an additional automatic locking mechanism).
Some such systems come with a user lockable central diff, like Land Rover Defender and Toyota Land Cruiser; some don't, like a lot of AWD/4WD passenger cars and crossovers.
Part-time systems can be engaged and disengaged by the driver, and don't have a central diff. They are usually meant to be driven in 2WD mode on normal roads and the 4WD mode is intended for loose terrains like mud, snow, sand, etc. Examples are the Jeep Wrangler, Toyota Tundra and Hilux.
There are part-time vehicles like the BMW shown in the video that can always be driven in 4WD mode but such solutions are not present on all part-time systems. These systems use some sort of an automatic locking mechanism, which could be a clutch, a viscous coupling, etc.
The reason I bothered opening the video was I figured the whiteboard too simple for this one and wanted to gripe. I've got an AWD system that looks identical to the 4x4 setup on the whiteboard.
I have to agree, 4WD = AWD, full time Vs part time is the big difference.
Thanks for explaining the part time and full time bit. You made me understand that my 2007 toyota auris with 4wd is actually part time. There is a button i press to disengage 4wd when im driving regularly. On sandy, wet and rough areas i engage it and the tires 'grip' the road better.
@@randrews25 Does the button you mentioned have the word "Auto" written on it?
I'm not completely familiar with that car's 4WD system, but based on what I've read you should be able to use the 4WD mode all the time. The system sends power only to the front wheels most of the time but when necessary, it will also send power to the rear wheels. Check the user manual to make sure.
IINM It is an automatic part-time system, pretty similar to the one in the video.
Explained perfectly.
My dearly departed Dad was the one who explained this "center differential" engineering to me since I was a child.
How about a video explaining 4WD/AWD systems in transverse engine cars? For example, Mitsubishi Evolution, Golf R, etc.. Awsome video as allways!
See the video description for a detailed look at the Evo’s AWD system. :)
@@EngineeringExplained How about the Celica GT4?
@@EngineeringExplained Thank you! :)
How 'bout mitsubishi super select II 4wd system?
I think he has, across different videos, described electronic, various mechanical, and open differentials as well as active torque vectoring, the most common name or at least what I call combining open differentials with brakes to "vector" the torque away from a slipping wheel by immobilizing it. Each AWD system is a combination of these differentials that can (think disconnecting axles) have all wheels connected to one or more engines.
THANK YOU FOR ANSWERING THIS, this is kinda what i thought, lack of a center differential, but it was NEVER clear anywhere i looked this discussion has come up so many times for me and i never had an absolutely certain answer for anyone
10% comments- Thanksgiving
90% comments- *Whiteboard*
One of the few rare videos that actually describe the differences properly
Could a 6 wheel G wagon have 4 wheel drive🤔
I'm pretty sure it has all-wheel drive, and 6 differentials.
Yes it could, if it only sends power to 4 wheels. It's the same principle with 2 wheel drive cars, which have 4 wheels of course
It would just be a 6x4 instead of a 4x4.
@@acarguy3773
What does the 4x4 mean? 4 wheels, 4 axles receiving power?
@@Appletank8 yep, exactly that. So a car with front or rear wheel drive only would be a 4x2.
One of, if not the best channel on TH-cam
The Skyline GT-R has had that since 1989 with the ATTESA E-TS system, only it wasn't user-selectable.
I drive a Hummer H2 and I honestly don’t have a clue how the 4wd system works. It’s supposed to be all wheel drive all the time and then when you need to you can put it in 4wd and lock the front and rear differential. I’d really love to see a video explanation on how the whole system works together if you think that would be a good idea for a video. Love the content!
Thanks for the clarity. 🤝 Keep up the good work! 👍👍
Great vid, as usual mate.
Cheers from Australia 🇦🇺
Awesome vid Jason! Closing in on 2M subs!
One of the very few TH-camrs whose every video I have clicked the like button !!!
I appreciate it, thanks for watching!
Didn't you have a video covering all wheel drive in the 911? You should put that one up there in the description too since that's a bit different with the engine in the rear.(I think you mentioned how it's effectively a rear wheel AWD system that sends power to the front vs most systems which are effectively front wheel that can send power to the rear.)
1994 Land Rover Discovery 1, 200Tdi, full time 4-wheel drive with a lockable transfer case. Best ride I've ever had. Ewarton, Jamaica.
Great explanation. I was wondering how they did that 4WD drive system. I would imagine it works well to help that car handle amazingly.
Easy way to remember which is which: "All" wheel drive is "all" the time (mostly).
WD40 wheel drive
Me with my beater I use for work
Thats slippery AF!!
WD40, the only deodorant an engineer needs.
This guy has top-list infos! I’d started to watch his vídeos since his 500k or so subscribers. Now he got +2,3mi and demonstrates the same motivation to spread his knowledge. Thank you for sharing...👍. Congrats, from Brazil!😉🍾
BMW GB are right - we Brits use the terms 4WD and AWD interchangeably, assuming the vehicle has four wheels, of course.
We also find it weird that Americans call just the gearbox the transmission, whereas we call anything from the clutch or torque converter to the driveshafts the transmission.
Where I live most people just say four wheel drive. Trying to differentiate AWD from 4WD when there's not really a clear cut line between what is what anymore only brings confusion.
Is that so? If any American ever moved there, it'd be hell getting used to that vernacular.
Interestingly, AMC Jeep made an all wheel drive, full-time Four wheel drive system back in 1973. It was called Quadra-Trac. I had one for 30 years. Does what AWD does, but then you can lock up the transfer case and for off road or when things get really shitty. it also has low range and neutral for towing. A fantastic system.
One of the problems with computer controlled AWD is that the power transfer can get flaky in conditions not programmed for. I have seen units nearly cause loss of control in a windy mountain road. Nice explanation. Thanks.
Is that with all AWD, or just synonymous with certain models?
@@danhill6176 Try again... As far as I know it's only my friend's SUV that does this. Not sure if they ever solved the issue.
@@danhill6176I would assume just certain cars. I have a Subaru and my AWD is phenomenal. I've taken it on dirt at triple digits speeds, drifted in snow and ice, never had any issues.
Easy Explanation for these drive-trains:
All-Wheel Drive = works on *ALL* drive-able surfaces~
4-Wheel Drive = works when *4* wheels need torque at the same time~
Also FYI @4:29, Audi created a AWD drive-train design like this BEFORE BMW did.
My 1987 Audi 5000 CS Quattro has a dial selector that lets the driver switch where the engine torque is being distributed: selections are front axle, rear axle, or both axles.
In 10 years, we'll start to see off-road 4x4 M5 builds that could rival the X5 capabilities
NIAtoolkit
Yea no ..
Daniel B
The X5 now has Air suspension and a intelligent AWD system and the car has modes for snow, sand and all that kind of stuff almost 9 inches of ground clearance and the M5 will need to loose it’s bumpers and side skirts in order to go off roading even with a lift do to the sporty nature of the design
Deoends if we still run on fuel 10 yrs from now
Mercedes already have the 4x4 squared E class with 17" of ground clearance, so BMW have some catching up to do...
So it would have 0 off-road capability because the x5 is just a car with a taller body???
OMG ! Why this channel has only 1.9mln followers ??? Great job !!! Nothing comes close !!!
The grey area is the few 4wd vehicles that have a center diff in their transfercase..... But they can lock it solid.......
Yes my Sequoia does this. I have 2WD, 4HI (unlocked), 4LO (unlocked), 4HI (locked), 4LO (locked). When the transfer case is in 4WD unlocked then its running through a TORSEN center diff so you get some torque bias to the wheels with traction.
Jeep Cherokees and grand cherokees had this as an optional transfer case. They had 2-hi, 4-hi(part time) 4-hi(full time) neutral and then 4-lo as options to select when driving.
Evil Me now those are the cars I call offroad worthy
@@Dganny24 Yup, NP242 trasfer case, specifically.
Great video def watch through full vid everyone. I love the technical and data based take you have man. Actual quality content!!!
AWD - Automatically handled by car's system and distributes power to where it's needed. Works on road and off road.
4WD - Manual, better off road.
So is awd basically a “smart” form of 4wd?
Sum Randum Guy
No, it’s a crap attempt at 4WD
Yes and no. The car removes the need for the driver to choose which wheels drive and when. The driver cannot even make the choice to go into 4wd (at least not in the Ford Kuga we have).
It will usually run in 2wd, but when it senses the need to direct some of the power to the rear wheels, it will do it quickly.
For those of us who prefer to have control over the drive and axles used, a 4wd is the way to go.
My old Subaru had a fuse for towing that would disengage the center diff. It wasn't "selectable" unless you wired in a trivial switch. :D I ran it as FWD every summer for a half dozen years and saved 2-3MPG.
Now, my old Chevy truck has a hoist pully for engaging the Hi or Low 4WD. I have to shift into Neutral for the Low to engage and it makes quite a "clunk" when it does so.
My current Honda calls itself 4WD but there's no clunk and even its diff-lock mode "VTM-4" can be engaged in 1st gear. Nice, but "lockable AWD" in my book.
BMW has tons of cool stuff but cant keep seals from leaking after 50k miles
One sells cars and the other sells costly parts!
The Nissan R32 GTR in the early 1990s had that exact 4WD system as that BMW (ATESSA). It has a clutch pack in the centre pressurised by a hydraulic pump. The car stayed in rear wheel drive until certain parameters were true (slip angle, yaw, steering angle etc), then it would transfer up to 50% to the front. Probably why it dominated in racing! Every GTR after that has an evolution of the ATESSA system.
Don't really understand why BMW had to reinvent the wheel here. The E63S managed a RWD only mode with AWD. And you said it, AWD is better in the corners.
Nevertheless it's nice tech.
Good video.
I will throw my two cents into the cup.
I will use a rear 4x4 drive vehicle as an example.
One rear wheel provides the power. When the 4x4 lever is pulled, the opposite front wheel then also has power. Not for driving on dry roads, and turning will bind. Like my former 1999 Pathfinder.
An exception is a vehicle with locking front and rear differentials. Both rear wheels have power. When the 4x4 lever is pulled, then both front wheels also have power. Not for driving on dry roads, and turning will bind. Like my former 1995 Pathfinder.
My dearly departed beloved 2002 Subaru Outback wagon with a manual transmission had All-Wheel drive. All wheels had power all the time.
One problem with that set-up is the tires all have to be the same circumference. The previous owner of this car replaced one bad tire instead of all of them. It had a larger circumference than the three worn tires. I bought the car not knowing either of these facts and had to replace the transmission. The clutch was worn, anyway.
Could be the automotive engineers have changed all this and never bothered to tell me.
Short answer : AWD= center diff vs 4WD= no center diff (dog clutch, clutch pack, etc)
SnowCat not exactly. The best 4 wheel drive ever built aka the 80 series land cruiser has a centre diff.
Great Video. This is an explanation of part-time 4WD, but doesn't cover "permanent", "constant" or "Full-time" 4WD.
Now, I hold the opinion that AWD is just permanent 4WD, like a Subaru for instance. AWD is simply a marketing term. In the Subaru's case, it has a viscous coupling system which carries out the same function as a multiplate clutch pack system or a centre differential. Some permanent 4WDs can select to lock the Centre Differential, thus changing from Full-time 4WD, to "True 4WD". (yes, I'm aware that front and rear axle lockers are technically required to induce "True 4WD").
I feel the difference is that the Centre Differential can be manually locked via a selection made by the driver, whereas the AWD system cannot.
All very amazing and expensive when it goes wrong!
You are one who teaches what we cant get in schools or teacher cant go the way you go
Easy, all wheel drive is when all of the wheels receive power from the transmission.
Four wheel drive refers to when only 4 wheels receive power.
Now give me an Engineering degree!
Get this man a diploma!
Engineering Explained Dang it he still my thunder !
Engineering Explained I knew my Subaru could become Rockcrawler 😂
@@EngineeringExplained Hey Jason, during the drive to university today I stumbled across a ~2010ish Mercedes C225 which had the 6.3 AMG badge on it (obviously fake) which got me thinking; is it better to have larger cylinders or more cylinders if you could choose one. Thanks, keep up the great work!
@@EngineeringExplained Wow, Savage
I have an AWD Ford Edge. Years ago, I had a Ford F150 4x4. One thing I learned....AWD-4X4, it ALL really depends on weather conditions. Both perform poorly on icy covered roads but, in my experience perform about the same in deep snow conditions. Only thing the 4X4 is 100% better at, is for helping to tow another vehicle.
You did a video on the Ford Raptor yes? That also has a clever drive system
Yep! Very similar in functionality! th-cam.com/video/HeVUt7AdbLI/w-d-xo.html
Yes, that Raptor is a clever girl.
Love tour videos. the difference is some 7,000-10,000 USD worth of repairs when these Magna Steir manufactured AWD start failing. Some had 3 units by 100,000 kms. F3x and X3s X5 2011-2018 are losing them so fast that there is a long wait for one. Am on the 6th month of this AWD transfer case, the new one having arrived from Germany early aug 2021, but WITH THE INCORRECT FLANGE for an F30! of course the front driveshaft was found out of balance due to some insulator foam that rubbed for who knows how long. New transfer cases shot up from 900$ USD to 5,000 USD for a 2021 revision. All and all, it started shy of year 6 and end of warranty but BMW could not find the source of the tiny vibration. TC failed march-april 2021. Remanufactured one was also defective. New one ended up 7,500$ CAD plus reprogramming plus a new driveshaft, all dine at an independent sports car garage that loaded me with discounts. total cost of fixing this on my 2014 M Performance is 8,000$ USD.... yes these transfer cases are badly designed and built for the torque and heat that we have these days. original one was fiund with seized bearings, and the whirrrrrrrrr, very very faint, kicked off 2019, car at 70,000 kms... so did vibrations in very rare condition (high speed turn ramp to the right)... anyways, if you can drive a RWD with winters, do so!
Thanks so much for the video
Just an FYI... that BMW transfer case is likely made by Magna. Magna makes Cfer cases for 60% of 4wd vehicles on the road. GM, BMW, Jeep, and many others use one of their variants.
Also, many Xfer cases these days have an Ultimate Combo that was not mentioned! My Chevy Colorado has 2wd, Auto, 4Hi, AND 4Low (And neutral mode for towing behind an RV). With “Auto” mode the center diff is unlocked like an AWD system so you can drive around on patchy dry pavement and not bind the drive train. 4HI and 4LOW locks that center diff. Enabling 100% of the power to be sent to any single tire instantly when off road(with locking diffs front and rear). As long as a single tire has traction. You won’t get stuck.
I noticed 2 weeks ago that the current gen CRV use AWD while the previous gens were using 4WD and yet, it's still the same system?! I guess they changed it for marketing?!
I have the 2002 Honda CRV and it is AWD but it's a little different than Jason explained. The car is always in Front wheel drive and power is always available to the rear axel but each rear wheel has it's own wet clutch system in the rear axel. The rear wheel axel clutches engage only when there is torque applied. So steady state road speed the are off, braking and coasting they are off but when you hit the gas pedal from a dead start there is enough of a torque load there to engage the rear wheel drive clutches. It works pretty good and can send some gravel or snow out behind you. It's taken me up steep snowy roads that front wheel drive cars struggled on. Having the rear disengage when the torque goes down saves gas. The new models are just the same.
Yeah the CRV is a reactive system, just like my Suzuki SX4 was. I don't like that, sometimes it reacts too late. I prefer by far how my Crosstrek works, I just wish it could have a turbo offered. :)
@@groovymotion5706 My CRV has no reaction lag at all. I can toss the rear end around in the snow just like a rear WD. Got to do that today too. It's a fun little SUV IMHO. I've got over 220,000 miles on it and the only significant problem was loosing the air conditioning compressor at around 170,000 miles. The Crosstrek looks like a great car. I might try that next!
@@mikeh2520 Yeah but it's still a reactive system. The SX4 was great for drifting but terrible for fuel economy! Yeah the CRV look extremely reliable! As for the Crosstrek, it's great for having 2 wheels on lots of snow and the others without, there is no torque steer. Only bummers are the terrible lack of HP and the fact that you can't totally disable the ESP...there is a way but just for below 50kmh.
Best description video I could find thank you EE!
Can you explain the failure mechanism caused by. Tires of slightly different diameters to awd cars? One flat means 4 new tires?
There is none, an AWD car can accommodate different wheel diameters as it has 3 differentials (Or other devices allowing wheels to go at different speeds like Fords replacing of the center and rear differential with 2 clutches, one to send drive to each rear wheel).
If the tires are different diameters, the differentials etc will need to compensate, and thus will heat up and wear faster. Usually you would replace 2 tires
Be careful if you ever tow any AWD vehicle. Never tow with only 2 wheels on a dolly. The speed difference at the center diff will be so great that it will blow itself apart. Some vehicles have front or rear axle disconnect for this purpose.
@@peglor That is actually incorrect. Just about all awd systems include a disclaimer that all tires and wheels need to be the same size and type or damage will occur. At most they were designed to accomdate the use of a manufacturer spare tire for a temporary period of time.
Interesting... in light of the different set-ups by manufactures: I asked a dealer mechanic/tech about my vehicle (AWD) and if it is always using all wheels or if it is automatically selective. His answer was that two wheels move the vehicle (saving fuel) until slipping is detected, then power is transferred to the gripping tires, whether it be two or three wheels as needed until traction stability is regained. In essence, mine acts like a 4WD automatic system. I thought that's was pretty cool not to share. Of course some vehicles use all four wheels all the time.
James May:
"I like him, he know's what he's talking about"
Finally, an explanation that makes sense! Thank you so much!
All wheel drive is when all 4 tires spin all the time at diffent speeds 4wheel drive is when you can have 2 or 4 wheels Spin at the same same speed all the time
What about full time 4wd and selectable AWD?
Succinct. I like it. Thanks.
I'd love to see you as a CEO of a large auto company. Such abundance of passion. Thanks for all videos! Such immense contribution.
More confused at the end than when I started.
Watch it again in reverse.
@@kennethclifford1863 😆
Zieg Aubrey 😂
Yes, because there is no clear definition for both. If you want all wheels possible to be driven you have to check how they are linked. That's it. Don't use marketing therms, just use engineering stuff and compare them before choosing a car.
My 2005 Ford Escape was a full time 4WD, or four wheel drive car. I enjoyed everything about it except feeding it fuel, That beast was thirsty. My 1015 F-150 is 4X4, or Four Wheel Drive but I do have a 4A setting , 4 Automatic, which runs like all wheel drive.
Very educational video. BMW should pay you for this review. lol
they didn't?
Love the semantics clear, straight, to the point.
Great video as always, but I disagree. There are too many different mechanical systems for just two terms. I do understand the colloquial differences between 4WD and AWD, but I have yet to see a consistent mechanical difference between them. The sole exception is that a system that has a low range is not called AWD, although there might be an exception to this too.
I view 4WD and AWD as technically and mechanically synonymous, with people generally using 4WD for trucks and SUVs and AWD for SUVs and cars.
There's definitely not as much of a difference between the two categories in newer vehicles than traditionally since car companies incorporating AWD features in 4×4 systems and vice-versa.
This was a very complicated way of saying one is permanment 4 wheel drive or manual selectable; the other is just auto selectable as needed, with AWD another wheel can be switched on and off in a fraction of a second; the car's mode control will set parameters for how quickly and in what proportion so is actually considerably better. For BMW drivers it doesn't matter people have only bought the badge, for American cars it doesn't matter because everyone lives in Hazard county and drives a Charger :)
So basically 4wd is the more primitive system where all wheels receive identical power at all times (unless it’s set to 2wd ofc), whereas awd is a “smart” variation of 4wd that’s adjusts power being delivered to each individual wheel as needed. Is this correct?
It is worth pointing out that in the UK, they do legitimately use 4x4, 4WD, and AWD interchangeably, even in cases where the hardware is distinctly different. I'm guessing this is mostly because for them, legit 4WD vehicles aren't all that popular, let alone necessary for most of their population.
It's kind of like Americans and the word "liberal", which basically became synonymous with socioeconomic leftist ideals, even though the actual definition is actually somewhat contradictory to that.
I think it probably a marketing thing, non car people will not care either way, but if four wheel drive sounds cooler in their simple minds then it might sell better.
It is the same in german, "Allrad, Vierradantrieb, 4x4" are used interchangeably.
@@nirfz the BMW website does it, as Jason showed in the video. Most people don't understand enough so they don't actually care or even notice.
@@acarguy3773that is true, but in german there has never been a distinction between the words, they were always used interchangably even by experts.
Or maybe a better explanation of what i mean: awd or 4wd or 4x4 were never locked to a working principle in german.
The distinction (if it was made at all), was made by adding the working principle to one of the epressions: "permanent, zuschaltbar, haldex, visco etc.") Nowadays of the 3 only "Allrad" seems to have survived in german.
@@nirfz aahh interesting. Maybe that is one of the reasons for all of the confusion then, even in English. I never knew any of that. I suppose it makes sense to do it that way though, and it gets rid of any ambiguity if they specifically say what type of system it is.
Mitsubishi Montero/Pajero has severals options of traction. It has a transfer case but also has a central diff. So it allows to select 2H, 4H, 4HLC, N, 4LLC. 2 Wheels drive, 4 wd with open central diff for using on tarmac, 4 wd with locked central diff for snow, gravel, sand... neutral, and 4 wd central diff locked and low range for maximun torque and low speed. It's quite reliable and I think is the most complete traction system since 90's.
4WD car with rear bias as the Nissan GTR if I'm not mistaken.
GT-R ATTESA is part time 4WD, i.e. it's RWD until the car detects slip, then transfers torque to the front diff via the transfer case.
@@nizm0man That is AWD, user selectable full time 50/50 front to rear bias is the common definition of 4WD used by everyone but europe apparently. All Wheel Drive is defined as any form of automatically variable and/or non-50/50 front to rear bias. At least that's the definition Japanese, American and Australian auto manufacturers have stuck to and the definition any layman in those countries would try to describe.
I was thinkikg about that too cuz if you search subaru imprezas for sale in nettiauto some say awd some say 4wd makes me confused asf that thise gc8 has 4wd and new ones awd
The AMC Eagle was an automatic all wheel drive. They were actually were fun to drive. The first ones were completely automatic, later models were selected drive with a selector switch. The 1980 model was the most fun, in my opinion.
Oof never been this early for an EE video 😎
Welcome!
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@@EngineeringExplained It never ceases to amaze me whenever you reply to my comments 😎 Cheers!
@@tako2291 Haha yooooo whats up
it's good to have life goals...
I've seen videos trying to explain the difference in a purely mechanical sense, and they just left me confused.
This video explains it in a mechanical and a practical sense, so now I have more of an understanding.
i always thought the difference is just wheter it is permanent or not. after this, the haldex system (golf) would be an 4WD system, but after this, it would be a AWD system, because it has a differential. And the system also distributes the power itself (but just when there is slip in the front as far as i know)
I don't think there's any real accepted definition. Centre diff is no good as a differentiator because many AWD systems don't use centre diffs - Subaru's automatic cars these days use a wet clutch pack that basically clamps the rear drivetrain onto the front drivetrain with a varying degree of grip so as to allow the rear to slip to rotate at a different speed. Many other AWD systems do this too, I'm pretty sure that any on demand system will because that would make the most sense for a system that's designed to only drive the rear (or rarely the front) in specific relatively uncommon situations.
Meanwhile you have 4WD systems that do use centre diffs - the LandCruiser uses a transfer case that instead of working like a traditional 4WD system is actually a low range gearset and a torsen limited slip diff with a diff locker on it to enable full locking. The G Wagen also uses a locking centre diff - no idea if it's limited slip when not completely locked though.
You could use the selectable function to differentiate but then you get grey areas with AWD cars that can have their operation driver controlled to an extent, like the Focus RS and the WRX STi, not to mention that full time 4WDs like the LandCruiser will happily work as a very good AWD vehicle even if the driver never touches low range or the locker. Maybe mechanically selectable? Really I think low range is probably the best differentiator because that seems to be the biggest limitation on how much AWD cars can do these days with increasingly sophisticated traction control.
Borg Warner Torque on Demand transfer cases pretty much do it all. AWD, 4Hi, 4Lo, 2wd at your disposal. I wish that it was used in more vehicles.
The M5 F90 is actually 4WD which is quite quirky on a sports sedan
So if I want to go drifting, I can just switch to RWD which is so much better than drift mode
Agreed!
You're drievshaft depiction is flawless.
Not to mention you'll get better fuel mileage with 2wd (if you want)
An ideal system has three Torsen differentials, one in the center and one for each axle. However, the problem here is the cost. So most manufacturers use one Torsen for the center and then traction control on each axle/tire.
AWD is more light duty, 4WD more HD.
paul lamont perhaps this is true in practice but it isn’t a technical requirement of either system.
The Pajero offers the same thing. It has a 4WD mode and a 4WDHLc Mode which locks the center diff while in 4wd mode. The Evo also has 4WD with the ACD acting similarly to a locked center diff in "snow mode"
can u explain about the six stroke engine patented by an Keralite. I really don't understand it
Hi. Can I remove the Transfer case chain in a Mercedes Benz ML320 and drive as a rear wheel drive car ? Thanks
The term 'AWD' is just a marketing term invented in the 90's to try to differentiate 4WD cars from 4WD off-roaders.
Man your presentation to explanation to the animation... Just rocks... Instant subscribe... Thanks for the video...
I'm not convinced he's right on this one. I think, as BMW state, 4WD and AWD are just marketing terms with no real definitions.
The term does not imply any particular design of centre diff.
I agree.
Yes agreed. There are no standard definitions.
As far as I am aware, "All Wheel Drive" term came into more common use to try and distance thoughts of heavy, thirsty 4x4s from smaller cars with 4WD.
My thought exactly. This just seems to be a marketing term for manufacturers like Toyota that build both on- and off-road cars to state that the 4WD system is completely different between the two. Which is likely to be true but is in fact the result of other components like being to able to lock the differential and select low gearing. Which given the ground clearance of this BMW you are very unlikely to find in there.
As far as I know, in german we don't use different words for the different systems. They are all called "Allradantrieb" - all wheel drive. Maybe that's why BMW states "it's all the same".
Excellent description. AWD = center diff, 4WD = transfer case. As someone who has owned 4WD vehicles, and was familiar with the transfer case, I wasn't sure how an AWD differed. Thank you.