Tesla Model 3 Dual Motor AWD - 4x4 test on rollers

[SwedishSTIle]

Haldex is garbage. They are FWD biased with unnecessary turns the system due to a transverse engine layout. They would not do as well in this test since barely any torque goes to the rear. MB uses three open differentials and cannot lock (fail), and BMW X Drive uses a chain to turn a forward shaft (fail). The only systems worth buying are Subaru manual transmissions (Viscous-Coupling Continuous and STI DCCD), and Audi longitudinal (TorSen center...not TT or A3, which is Haldex). Subaru Active (CVT/AT) system is the best clutch-based center system, because it always sends power back 60/40 and has a longitudinal engine layout (Symmetrical). A 4x4 would need to slow down, lock the center differential, and then disengage above 30 mph. The benefit of Subaru DCCD is the ability to have 3 mechanical differentials, including the driver controlled center, which can fluctuate the amount of lock as 59:41 to 50:50, to allow enough slip for high speeds. I'd rather that than needing to lose traction with a RWD based 4x4 until I slowed down to a crawl..

Ok, before We go back and forth here, I have actually owned and driven all of these systems in the real world, my understanging of them is both technical (im a mechanical engineer), theoretical, and empirical:
2008 Subaru WRX STi Hatch
2015 Audi Q5
2014 Bmw X3
2016 GLC 300 4Matic
2015 Ford F-150 4x4 with electronic locking rear and TrueTrac front on 34's
2018 Volkswagen Atlas 4Motion (current)
2016 Mercedes Sprinter 4X4 (current)


Haldex systems are are efficient and exceptionally capable. I guess you dont own any cars with a Haldex in it. Most clutch based systems are very tuneable and very good on slick surfaces. Every driven a car with a clutch based limited slip rear? They are awesome.
A quick search and the Tiguan seems to do pretty good.

I have a 4x4 Sprinter with selectable 4matic as well as an Atlas 4Motion. My last large vehicle was a 15 F-150 4X4 with electronic locking rear and a TrueTrac front. I could shift on the fly into 4X4 at any speed (didnt need to slow down) and the TrueTrac is always active (electronic locking rear drops out above 20mph). In snowy/icy conditions the Atlas is one of the the best vehicles I have owned, and my sprinter is completely unstoppable as was my truck.

Is haldex complicated? Yes. Is it also a very good system? Yes.

I didnt dig her out, I drove her out, and then flattened the parking lot for my neighbors with her.

I know a thing or two about 4wd and AWD vehicles and systems, as well as driving them.

On the other hand my Subaru STI with a 6speed, DCCD center could easily stick two tires on one side and spin the other side indefinitely, overwhelming even the DCCD set to full "lock:". And thats with Blizzak tires in mixed snow and ice.

I wanted to believe when I owned the Subie that it was the best winter vehicle. When it comes to control at high speeds in adverse conditions, I would not trade it for anything. But for getting out of deep snow, getting unstuck from freeze/thaw conditions, and other situations simulated by rollers, it just wasnt that capable in comparison to more dedicated 4X4's.

Your knowledge of classic 4x4's seems to be about 20 years old. Modern 4x4 trucks have 4A which is shiftable on the fly, and is code for 4 automatic, and it will engage the front drive shaft as needed on the fly for mixed dry/snowy conditions. 4x4 is also shiftable on the fly at ANY speed these days. Gone are the days of getting out and locking your hubs, or shifting to neutral to engage 4x4.

 

[SammichLover]

I'd call the Model 3's traction control system brutally effective in the snow and ice. Just stay on the throttle and don't apply steering corrections; let the car sort its way out. It's not smooth, but it does work.

None at all or just smaller corrections? That's what I've found on other loose surfaces. Staying on the accelerator too much seems to exasperate T/C S/C interjections, but I'm not 100% about that. That'd take proper data dump to confirm.

In the meantime I'll leave this fun clip I've just downloaded from my trip.

You'll need to up your bitrate to HD to read the sign.

 

[Daniel in SD]

Distance matters. You certainly won't recover all of the waste heat, and the further the extra induction motor waste is out from the coolant the less it'll help.

The coolant goes through the induction motor housing. I'm not sure what you're saying. It's just as close to the battery as the rear motor (not that it would matter).

Citation?

Soft hands, gentle foot, Stay Frosty(tm). This isn't some weird new thing for the Model 3.

The Model 3 is "weird". It drives like a RWD car in the snow but if you drive it like a RWD car you're going to have a bad time because the computer will all of a sudden start sending power to the front wheels. It works but it's just kind of crappy.

 

[SammichLover]

The Model 3 is "weird". It drives like a RWD car in the snow but if you drive it like a RWD car you're going to have a bad time because the computer will all of a sudden start sending power to the front wheels. It works but it's just kind of crappy.

BWHAHAHA

Exactly how the Model 3 behaves is new. Stay Frosty(tm) isn't and is as applicable as ever.

<edit> "Don't drive it like the vehicle it isn't or you'll have a bad time" would also be in the Not New category.

 

[Daniel in SD]

BWHAHAHA

Exactly how the Model 3 behaves is new. Stay Frosty(tm) isn't and is as applicable as ever.

New does not equal good.
If by "stay frosty" you mean letting the computer do all the work then I agree. If you're driving a car without nannies I would advise counter steering a little bit.

 

[Daniel in SD]

Says the guy that's constantly on about how AWD sucks compared to RWD.

It’s not that complicated. In slippery conditions AWD is superior. When you have traction RWD is superior.

 

[Snow Drift]

I stand corrected. What I meant was an AWD system with a center differential.

If the center was open, yes.

I'm surprised the Rav 4 Hybrid fails this test so badly with the front wheels on the rollers. Doesn't it have an electric rear motor with no driveshaft/center diff?

That e-motor really can't push a 4k lb car by itself. It's a very poorly made system for grunt work.

Ok, before We go back and forth here, I have actually owned and driven all of these systems in the real world, my understanging of them is both technical (im a mechanical engineer), theoretical, and empirical:

Had to delete as there was a lot of content.

I'm sorry but Haldex cars fail 1st by having a transversely mounted engine which unevenly distributes weight across the front of the car. 2nd, the car is FWD until slip...yes, some have a 50/50 pre-load, but the reality is, it's mostly Front-wheel biased. 3rd, there's no center differential. 4th, the Haldex system is not mechanical and instead uses clutch-packs and fluid pressure to push together when there is slip. This much weaker than a Planetary Gear (STI, old DSM) mechanical center differential, or TorSen, or Viscous Coupling.

It is a cost effective system to provide mediocre grip. Small Audis, VW, Ford and the Swedes use it, but it's not nearly as good as it could be.

Oh, love the STI...I had a 2018 STI, 3 WRX and a Crosstrek.

 

[SammichLover]

New does not equal good.
If by "stay frosty" you mean letting the computer do all the work then I agree. If you're driving a car without nannies I would advise counter steering a little bit.

It means "Don't overcompensate, overreact, let things develop naturally and make the necessary small corrections that'll make the best of the situation you've got." <edit> Primum non nocere.

Your "IT IS ALL DUMBED DOWN NOW" reactionary BS need not apply.

 

[EVDRVN]

If your nerves aren't up for a bit of a wiggle now and then you probably should have stayed home. Having no tolerance at all for slip angle is nanny overkill.

I have no issue with it, some people have steep narrow driveways and if you drift off you may end up on the side of a hill upside down. I often go on some tight spots and I would not want to drift into a wall. I was just driving mine in the snow last week and it did some off things in the rear that can be resolved.

 

[GregD60]

If I ever find myself stuck on rollers then I'll be happy it does. A vehicle with a locked center differential would do better on the roller test than the Model 3 but I'd much rather have a vehicle with a Torsen center differential for actual winter driving. The roller test is not a great test of real world conditions.

I agree that you don't want all your differentials locked up for slippery winter driving conditions, but a locked center differential is fine. In my Jeep Wrangler, when it gets slippery, I stick it in 4WD Hi, but I don't lock the front or rear differentials and it works very well. The problem with having everything locked up is that you can be spinning all 4 tires, and if it's really slippery ice, you can slide off the road in whatever direction it's sloped; you're better off having at least one tire not spinning to help keep the vehicle from sliding off the road.

 

[Daniel in SD]

It means "Don't overcompensate, overreact, let things develop naturally and make the necessary small corrections that'll make the best of the situation you've got." <edit> Primum non nocere.

Your "IT IS ALL DUMBED DOWN NOW" reactionary BS need not apply.

It’s not dumbed down, it’s just not very good. My other car has a Torsen center diff and all the nannies and it works better.

I agree that you don't want all your differentials locked up for slippery winter driving conditions, but a locked center differential is fine. In my Jeep Wrangler, when it gets slippery, I stick it in 4WD Hi, but I don't lock the front or rear differentials and it works very well. The problem with having everything locked up is that you can be spinning all 4 tires, and if it's really slippery ice, you can slide off the road in whatever direction it's sloped; you're better off having at least one tire not spinning to help keep the vehicle from sliding off the road.

Snow doesn’t stay on the roads very long in California so you’re often going between dry pavement and snow so a locked center diff isn’t great.

 

[SammichLover]

It’s not dumbed down, it’s just not very good. My other car has a Torsen center diff and all the nannies and it works better.

OR you're not actually using it as intended/optimally. Because you're freaked out by it being "weird"? ¯\_(ツ)_/¯

P.S. You're trying to tell me that "letting the computer do all the work" isn't an intended jab in the grump ol' man vein? BWHHAHA

 

[GregD60]

None at all or just smaller corrections? That's what I've found on other loose surfaces. Staying on the accelerator too much seems to exasperate T/C S/C interjections, but I'm not 100% about that. That'd take proper data dump to confirm.

In the meantime I'll leave this fun clip I've just downloaded from my trip.

You'll need to up your bitrate to HD to read the sign.

You really don't need to make any steering corrections; the car will do it for you, just steer where you want to go. I'm not suggesting flooring it, but give the accelerator enough to break the tires loose and let the traction control work.

I live on a road with a pretty steep hill that I can see from my office window; it's entertaining watching various cars try to get up it when it gets icy. There are some days when 2WD on full snow tires can't make it, and the 4WD and AWD cars struggle. It's also good for experimenting. On the most slippery days this last year, and we had a few good ones, my Model 3 on Sottozero 3s, would accelerate up the hill fairly quickly, but if I was pushing it, the rear would move from side to side and kind of slither up the hill. Doing so, I think it probably went up the hill faster in those conditions than any other street vehicle that I've driven.

 

[GregD60]

It’s not dumbed down, it’s just not very good. My other car has a Torsen center diff and all the nannies and it works better.

Snow doesn’t stay on the roads very long in California so you’re often going between dry pavement and snow so a locked center diff isn’t great.

I agree. I only engage the 4WD here when it gets too slippery for 2WD, and put it back in 2WD when traction improves. It's easy to shift back and forth in my Wrangler. It's hard on the drivetrain to have a locked center diff when the tires can't easily slip a bit.

 

[SammichLover]

You really don't need to make any steering corrections; the car will do it for you, just steer where you want to go. I'm not suggesting flooring it, but give the accelerator enough to break the tires loose and let the traction control work.

I live on a road with a pretty steep hill that I can see from my office window; it's entertaining watching various cars try to get up it when it gets icy. There are some days when 2WD on full snow tires can't make it, and the 4WD and AWD cars struggle. It's also good for experimenting. On the most slippery days this last year, and we had a few good ones, my Model 3 on Sottozero 3s, would accelerate up the hill fairly quickly, but if I was pushing it, the rear would move from side to side and kind of slither up the hill. Doing so, I think it probably went up the hill faster in those conditions than any other street vehicle that I've driven.

“Don't need to” is not the same as “shouldn’t”, “can’t”, or “optimal”. It just means you can get by on that for some given arbitrary requirement.

 

[Daniel in SD]

OR you're not actually using it as intended/optimally. Because you're freaked out by it being "weird"? ¯\_(ツ)_/¯

P.S. You're trying to tell me that "letting the computer do all the work" isn't an intended jab in the grump ol' man vein? BWHHAHA

It’s both weird and bad. I wasn’t freaked out because it’s quite obvious what’s happening when you actually drive it in the snow. The rear end slides out and then the car sends torque to the front. You sort of slither along. It works but I’d prefer it just send torque to the front wheels to begin with.
I may be a grumpy old man but the “let the computer do all the work” is advice to people who may try to correct the skid. My Lexus has traction and stability control and it’s much more seamless so this isn’t a rant against nannies in general.

 

[SwedishSTIle]

If the center was open, yes.


That e-motor really can't push a 4k lb car by itself. It's a very poorly made system for grunt work.


Had to delete as there was a lot of content.

I'm sorry but Haldex cars fail 1st by having a transversely mounted engine which unevenly distributes weight across the front of the car. 2nd, the car is FWD until slip...yes, some have a 50/50 pre-load, but the reality is, it's mostly Front-wheel biased. 3rd, there's no center differential. 4th, the Haldex system is not mechanical and instead uses clutch-packs and fluid pressure to push together when there is slip. This much weaker than a Planetary Gear (STI, old DSM) mechanical center differential, or TorSen, or Viscous Coupling.

It is a cost effective system to provide mediocre grip. Small Audis, VW, Ford and the Swedes use it, but it's not nearly as good as it could be.

Oh, love the STI...I had a 2018 STI, 3 WRX and a Crosstrek.

In the real wold the Haldex works very well. When it is well programmed it is fast, has efficiency benefits and places the primary drive at the front wheels which is boon for most average drivers with less than stellar car handling prowess. Like I said, and take it for what it is, as I generally HATE the Atlas that my wife and I bought, its a cheaply made mediocre care with bad gas mileage: Its phenomenally capable in the snow. I can put it in snow mode, turn the VDC off and hoon the *sugar* out of it. It gets unstuck, climbs steep hills, is completely transparent when ripping it around a corner (you dong get the usual slip, delay, power transfer that you can with FWD biased systems of yore). The Gen 3 and up Haldex would not be good for crawling because of the potential of overwhelming the clutch packs, but the same is true of viscous differentials. Torsen's in the back tend to cause push which is bad news for anyone who does not know how to control oversteer. Also plannetary diffs cause eratic behavior because when one wheel hits a patch of ice, the other side grips like crazy and can jerk you around. Clutched and viscous diffs are much more predictable and better suited to the average driver in wintry conditions.

And dont forget the newest Haldex systems can send 100% of torque to the rear wheels. Something the Subies and non haldex Audi's cant do.

If you are Block or Pastrana, not on mixed surfaces, or in a track car on dry or even wet surfaces, then I agree. But absolute performance is not important for slow speed maneuvers and getting unstuck and mixed surface/friction coefficient driving.

I can tell you with certainty, that if you drive an STI into snow that is too deep, the tires on one side of the car will spin and those on the other side will remain motionless. Does not matter what setting you place the DCCD in, traction control on/off etc. You can overwwhelm it. To that end the latest WRX with the brake based torque vectoring is probably a more capable system, even with the CVT, in those scenarios.

No offense to my beautiful M3, but I will take my Van or Atlas over it any day of the week in the snow. Cold batteries, loss of range, low ground clearance, I dont care how quick it is, the Van will go through ANYTHING, and the Atlas is just plain easy to drive in crummy conditions.

 

[SammichLover]

low ground clearance

I'm beginning to wonder how much this matters in most snow. Deep, refrozen iced ruts/ridges on an unmaintained street is clearly an issue when having only 13cm+/- of clearance, but the bottom is so consistent front to back with virtually no interruptions to hang up that I'm not sure how much a highpoint risk it has in just snow.

I've talked to a rural Saskatchewan Model 3 owner, had their's for over a year now, and he had no problems with heavy snow drifting over roads or his yard.

P.S. I haven't talked to those living in Regina, where they often leave the snow build-up into ice pack on the roads until the spring clears them. I guess this isn't the only low slung vehicle that navigates those roads but they might have a more treacherous time navigating on the side streets.

 

[AlanSubie4Life]

That e-motor really can't push a 4k lb car by itself. It's a very poorly made system for grunt work.

I guess that is what the evidence suggests. Looks like the rear motor generates 96lb-ft of torque with a final reduction of 6.86:1. (659lb-ft) With 14-inch radius tires that means 535lbs can be applied to the ground at the rear tires. A bit surprised that's not enough to budge the vehicle off the rollers, but hard to argue with the results. I guess those rollers are pretty steep.

 

[bijan]

I'm surprised the Rav 4 Hybrid fails this test so badly with the front wheels on the rollers. Doesn't it have an electric rear motor with no driveshaft/center diff?

I think the 2019 hybrid RAV4 does. He has a video of that too. It does better and only fails the two front wheels and one rear wheel on rollers.