After years and years of hearing shit about haldex and how it is not a real awd I am surprised. I actually works and based on this video I recommended 2014 Passat 4motion for my father.
@@DuBstep115 I traded in a 2011 Outback for a 2019 Golf Alltrack 2 years ago and the Golf is the first vehicle I’ve truly loved. Put a set of Nokians on last fall and it’s excellent in the snow.
Yes. But it’s also a matter of the powertrains and gears. To shift successfully the total torque to one single wheel shows also the good quality and mechanical robustness of the 4MOTION system.
Not sure what's in that subaru but I know my old forester with the symmetrical awd system was very effective. I used in in snow and also towing a boat up a very slippery ramp. It did as well, if not better than my land-rover in that situation. Currently, I own an older passat with the Haldex system. It works pretty well . I don't tow with it any more but it's coped well enough with snow. I would expect the more modern Haldex in the passat above to be better. I'm guessing they've improved it since mine, a 2008 model, was built.
Do you happen to recall what class of tires were on each? I live in the USA so my understanding is European all seasons are the equivalent of “all weather” tires here.
That would be interesting. I drove a Sharan (2.0 TDI, DSG, 4MOTION, 190hp) more than 200k km. On the autobahn (sometimes >200 km/h) and through ice, snow, mud. An excellent car!
@@martinsvensson6884 I don't know either. The Subaru's basic awd transmission is not technically exceptional. The only particularity, which influences the driving behavior, is the left-right symmetry. On the first Impreza WRX, a simple fulltime transmission with diff+visco in the middle and a diff+visco in the rear. A Toyota Celica GT4 had the same thing in the middle and a Torsen in the back... It's mostly that Subaru built its image on the all-wheel drive.
Its probably because the Passat has an Electronical "locking" diff. meaning if one Wheel (the one with the less traction) starts slipping it gets braked. The other Wheel with the traction will now receive the Outgoing torque. Its one of the Easiest and cheapest ways to make a "locking" differential, because all you really need is a ESC-Control Unit.
@@kingjulien1717 But I cant imagine Subaru not having that... Its going to be a part of the esp system regardless. I think virtually all cars have had that for a very long time now. MB for example got simulated diff lock as standard even on their 2WD models from 1996 and onward... That was the base minimum you would get already back then. And also, without such a system the Subaru wouldnt have gotten off the rollers at all. If there werent some form of diff brake.
The thing about viscous couplings is that the viscous fluid does wear out over time and it is clear that has happened here to this Subaru. A better tuned traction control system could have overcome this, but that wasn’t really a top priority when this car was made as ESC was just becoming mainstream. It seems that this center diff is basically acting as an open diff. It did still work some, as was visible with the front and rear wheel slip tests, but the viscous coupling would have locked up faster and more completely if it was new. Additionally, had the viscous coupling been newer, the spinning wheel opposite the wheel with traction in the 3 wheel slip tests would have required less braking intervention to reach the level of tractive force necessary to overcome the resistance of the three rollers. The Haldex system in the Passat should of had an advantage in these tests as full torque transfer would occur to the tractive axle without ESC intervention since slip cannot occur between the front and rear axle when the Haldex clutch is locked up. With this in mind, if we consider that that 100% should be available to the rear axle (in the 3 wheel slip test with one rear wheel also on the roller), assuming a properly tuned traction control system would apply sufficient brake pressure to the spinning wheel on that axle (the system allows much more slip on that wheel in reality) such that 50% of the drive power would be converted into heat (as a result of brake application) and 50% would be available as propulsive force at the tractive wheel. In the other case, let us assume the Subaru has a viscous coupling that is only capable of a locking value sufficient to support a maximum of 60% (90-95% at maximum should be possible in a new unit) at the axle capable of applying propulsive force. We can see now that this would now only leave a maximum of 30% available at the tractive wheel (in the three wheel slip test) since the other 30% would be wasted as heat. And remember that is the best case scenario, and considering the ESC system is not sophisticated enough to compensate for this liability, it will be essentially impossible for this subie to generate the propulsive force necessary to push the vehicle out of the divets created by the three rollers.
Actually it is the opposite - worn out visco usually gets locked/glued while new one is more open. Of course it depends on how many kg is there. We tested a few cars with visco and all of them were locking the diff in similar way.
I suppose then it would depend on the way in which the viscous coupling is worn. I too have seen cases I which a viscous coupling became like glue inside and basically acted like a locked center differential, causing serious binding and drivetrain distortion (someone did a video about a 2003 Mercury mountaineer with this problem). But fluid can also leak, lose viscosity, or the metal plates can wear down and each of these problems can cause a reduction in the maximum locking value.
@@john958 Check the video below, the last test. Haldex is actually not locked, it is building the pressure in controlled way up to the point when car starts to move: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-chenbeaft90.html Here is another interesting video of Subie - the same car but one with visco and another one with clutch-pack (haldex like type of awd system): ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-NHV79vZYmbQ.html It also increases the pressure gradually.
@@4x4.tests.on.rollers You also have to take into account that currently, many Subaru with diff+visco in the center don't have visco-coupling set very "hard", especially when they are not sports cars. And since a viscous coupling is not an electronically controlled system, a very hard viscous coupling could make the car much more complex to drive, bringing it closer to a car without center differential. Not to mention that it must remain compatible with all electronic driving aids -> softening. An electronically controlled system doesn't have this kind of problems since now all systems interact. It is therefore much easier to combine a system capable of torque reversal or very important blocking when the situation requires it with daily flexibility. But here, we can clearly see that it's not really a visco problem since the Outback passes the first test, but a traction control problem.
Volkswagen for the win. Yet more proof that Subaru awd is good, but far from the best. Subaru marketing and public perception believes that Subaru is undisputed leader of awd systems. Far from the truth. Subaru trolls and fanboys will say this test is unfair or biased.
