4Motion - high price

[Corradobrit]

Put the right tyres on, set at the right pressure and there isn't much the Haldex system can't handle. Plenty of YT vids showing its performance over tricky terrain.

 

[Velma's Dad]

This all highlights how the 'best' AWD/4WD setup depends entirely on where you want to go.

For rock-hopping or tackling sand dunes of the Great Erg, a "true" 4WD system is deffo what you want, probably with a simple centre transfer box (so full drive to both axles, all the time 4WD is manually or electro-mechanically engaged), and fully lockable front and rear diffs.

But for roads, including unsurfaced ones and/or covered in snow or muck, a modern AWD system with an active centre diff run by very sophisticated clutches, hydraulics and electronics will give you the best ability to make fast progress. It's what's been used in rally cars... until very recently the regs for Rally1 WRC cars outlawed them because diff mapping was becoming an expensive arms race.

Horses for courses.

 

[Tarquers]

Really helpful link. Thanks @Tarquers
I am glad I ordered the rear diff lock on our Cali which is due to arrive next year.

It is a pity VW didn't incorporate individual wheel braking into the traction control system.

My van in the video so it was fun to see the difference in the ways things work. ESC does zero to traction, but the diff lock completely removes slip when starting off, unlike traction control. It’s the low speed control that it provides that is the benefit I think in low traction situations unlike conventional TC.

 

[Calimili]

My van in the video so it was fun to see the difference in the ways things work. ESC does zero to traction, but the diff lock completely removes slip when starting off, unlike traction control. It’s the low speed control that it provides that is the benefit I think in low traction situations unlike conventional TC.

It's clear from your video that the Diff lock removes any slip when starting off. For normal use in slippery conditions, not hard off road, the new Cali seems to be able to handle just fine without the diff lock, with the combination 4M and TC, less "elegant" out of a situation with high revving until the TC kicks in, compared to effortless Diff Lock.
The last situation in the video though, just one rear wheel not on rollers, shows the TC has no influence on the rear axle and only with Diff Lock is the van able to move, regardless of revving.
What I would be interested to know is, should the last test be repeated, if, without diff lock, but applying gradually more handbrake combined with revving, the van would be able to move forward. The theory being the handbrake reduces the slip on the rear wheel on rollers, but no so strongly to impede the rear wheel without rollers to inch forward.

 

[Calimili]

Applying the handbrake gently has a similar effect to the diff lock, by slowing down a spinning wheel it sends drive to the one that isn't spinning.

That's what I think it seems plausible. Did you have the chance to test this in practice ?

 

[Tarquers]

It's clear from your video that the Diff lock removes any slip when starting off. For normal use in slippery conditions, not hard off road, the new Cali seems to be able to handle just fine without the diff lock, with the combination 4M and TC, less "elegant" out of a situation with high revving until the TC kicks in, compared to effortless Diff Lock.
The last situation in the video though, just one rear wheel not on rollers, shows the TC has no influence on the rear axle and only with Diff Lock is the van able to move, regardless of revving.
What I would be interested to know is, should the last test be repeated, if, without diff lock, but applying gradually more handbrake combined with revving, the van would be able to move forward. The theory being the handbrake reduces the slip on the rear wheel on rollers, but no so strongly to impede the rear wheel without rollers to inch forward.

I will reach out to the guys with the rollers and see if we can do it in the new year at some point.

 

[andyinluton]

That's what I think it seems plausible. Did you have the chance to test this in practice ?

Only on 3 litre ford capris. In my missspent youth, back then it used to snow in winter & traction control consisted of adding bags of sand in the boot.


There’s no fancy electrics that cut the drive when the handbrake is applied so no reason that it wouldn’t. Need to be sensible though you don’t want to overheat the brakes.

 

[RockinNRollin]

I have to say I've been impressed with the traction of our FWD Cali; maybe it's the added weight, but on wet steep roads / leaves and even muddy fields, I've not yet (touchwood) had any traction issues. The only time the wheels have broken traction at all in over 3000 miles is on a roundabout where I sprinted for a gap in the wet - I do find when setting off from a standstill "with vigour" the DSG can be a bit clumsy with the power application.

That said, I owned a Subaru Forester for years so I can also appreciate the capability of a good AWD system (and it was needed with a 2.5 litre turbocharged boxer!).

 

[Californication69]

An unlikely scenario for the majority of Cali owners

I try, but it always stays on the ground

 

[Californication69]

Beware the VW marketing machine. They tell at least one lie in the links. The Haldex is a type of rear differential that is an unengaged clutch pack for the majority of the time. Everything spins at the same speed and the clutch engages when needed ie when slip is detected.

From a traction perspective it adds up to 50% torque to the rear axle maximum but if a wheel is off the ground then all bets are off without a diff lock. It’s definitely better than FWD in low traction scenarios but it isn’t 4WD by any measure.

View attachment 117451

When pressing on out of a junction, I’ve had the rear right wheel spin, so it feels like it sends more power to the rear sometimes.
It’s a totally different feel to driving a 204 FWD California Ocean.

 

[Velma's Dad]

I have to say I've been impressed with the traction of our FWD Cali; maybe it's the added weight, but on wet steep roads / leaves and even muddy fields, I've not yet (touchwood) had any traction issues. The only time the wheels have broken traction at all in over 3000 miles is on a roundabout where I sprinted for a gap in the wet - I do find when setting off from a standstill "with vigour" the DSG can be a bit clumsy with the power application.

Yes the basic FWD vehicle is pretty good, as it should be with plenty of weight over the driving wheels. In seven years I've never managed to get it stuck anywhere. Even when towing a trailer which I do a lot, sometimes up to 1.8 tonnes loaded, the front wheels have only scrabbled for grip once or twice, when starting on a slippery hill (important to have not too much trailer nose weight of course). 4Motion would be nice to have but I can live without it.

 

[RockinNRollin]

Ultimate test for mine was on Birker Fell in the Lake District; I got trapped by cars on the steepest section (travelling uphill!) so had to stop - it's somewhere in the region of 25% at that point. The hill-hold worked and the van pulled away without any drama, even though the road was wet and the surface poor. I was very impressed.

 

[Roger Boeken]

You certainly are getting confused!

The 60/40 split is correct for a Cali & that information comes from the VWCV web site & specificaly mentions the Cali & GC

The 90/10 split & the webpage you've referenced are on the VW car site.

Also note that if something says that the same system is used as the touarag that different generations of that vehicle have had different systems.

you should start reading little more about 4 wheel drive , called 4motion by vw.
all cars with haldex ( not only vw, haldex is not owned by vw) are 2wd until front wheels risk to start slipping and then haldex sends power to rear axle. To improve reaction time haldex sends always minimum 10% to non slipping wheels. Cars with torsen diff are typical off road vehicles where front and rear axle are permanently powered and power can shift partially more to front or rear, 60:40 standard , 70:30 or 30:70 possible.
Haldex will react in many situations and very fast (20 ms, 15° wheel turn). But when you drive at constant speed it behaves as 2wd ( 90:10 not 60:40) If you drive long trips at constant speed, front tires wear more than rear tires.
transporter and cali use haldex. The uk website you refer to makes a wrong suggestion and is the only website making this suggestion, it is a simple mistake of the maker of the particular webpage.

 

[Corradobrit]

you should start reading little more about 4 wheel drive , called 4motion by vw.
all cars with haldex ( not only vw, haldex is not owned by vw) are 2wd until front wheels risk to start slipping and then haldex sends power to rear axle. To improve reaction time haldex sends always minimum 10% to non slipping wheels. Cars with torsen diff are typical off road vehicles where front and rear axle are permanently powered and power can shift partially more to front or rear, 60:40 standard , 70:30 or 30:70 possible.
Haldex will react in many situations and very fast (20 ms, 15° wheel turn). But when you drive at constant speed it behaves as 2wd ( 90:10 not 60:40) If you drive long trips at constant speed, front tires wear more than rear tires.
transporter and cali use haldex. The uk website you refer to makes a wrong suggestion and is the only website making this suggestion, it is a simple mistake of the maker of the particular webpage.

Not completely correct. Depends which Generation Haldex system is installed on the Cali (likely latest gen 5). There have been 5 iterations. If a latest gen unit is installed then the split is 100:0, so all FWD until rear traction is needed. Here is a break down of their particular characteristics:


Generation 1:

This unit is fitted to vehicles such as the Mk1 Audi TT, Audi S3 8L and Mk4 Volkswagen Golf 4motion. The unit uses a mechanical oil pump as the primary source of oil pressure. A minimum engine torque split of 90% front and 10% rear power split is achieved with a maximum of 50/50 split.

Generation 1 Haldex is a reactive system and does not rely on any complex input data from the vehicle. The unit uses a replaceable paper oil filter and requires regular servicing.

Generation 2:

This unit was also mechanically operated but with simplified components such as oil control valves and galleries. A minimum torque split of 95% front and 5% to rear can be achieved with maximum distribution of 50/50 front to rear.

This unit is fitted to vehicles such as the Mk5 VW Golf R32, Audi A3 8P Quattro, and the early Mk2 Audi TT.

Generation 3:

The third generation was not used in any Audi or Volkswagen vehicles.

Generation 4:

The Generation 4 Haldex is a proactive system. It looks at ABS control unit and engine ECU data and can prime pressure to the clutch to allow for faster activation when needed. The unit has a 100% front to 0% rear torque split when not activated with a maximum of 50/50 torque distribution and uses a cotton filter in place of a paper element.

It also uses a more simplified oil system and an electronic pump that was used as the primary source of oil pressure for the first time.

The unit is fitted to vehicles such as the Facelift Audi A3 8P, later versions of the Mk2 Audi TT, Mk6 VW Golf R, and VW Tiguan.

Generation 5:

This unit has further reduced complexity, size and weight. It’s achieved by removing the pressure accumulator and control valve found in the Generation 4 Haldex and replacing with a simplified pump bypass system.

The control unit has been revised to allow for better proactive functions and, like the Generation 4 Haldex, uses inputs from the ABS and engine ECU to achieve this.
The Generation 5 Haldex also uses an oil strainer in place of a paper or cotton filter.

The unit is fitted to most of the current vehicles such as Mk7 VW Golf R, MQB Tiguan, Audi A3 8V, Audi RS3, Mk3 Audi TT and Audi Q3.

 

[WelshGas]

you should start reading little more about 4 wheel drive , called 4motion by vw.
all cars with haldex ( not only vw, haldex is not owned by vw) are 2wd until front wheels risk to start slipping and then haldex sends power to rear axle. To improve reaction time haldex sends always minimum 10% to non slipping wheels. Cars with torsen diff are typical off road vehicles where front and rear axle are permanently powered and power can shift partially more to front or rear, 60:40 standard , 70:30 or 30:70 possible.
Haldex will react in many situations and very fast (20 ms, 15° wheel turn). But when you drive at constant speed it behaves as 2wd ( 90:10 not 60:40) If you drive long trips at constant speed, front tires wear more than rear tires.
transporter and cali use haldex. The uk website you refer to makes a wrong suggestion and is the only website making this suggestion, it is a simple mistake of the maker of the particular webpage.

Not my experience of tyre wear over 125,000 miles and 5 sets of tyres. Wear has been equal front to rear N/S to O/S.

 

[RockinNRollin]

Swings and roundabouts; the haldex setup is probably more fuel efficient and a "get you out of a sticky spot" type system, but probably less of an impact during driving than say the Subaru Symmetrical AWD which genuinely changed the driving characteristics as it was distributing power more evenly across all the wheels before a change in traction, rather than haldex which I believe is reactive to traction losses. Probably why my forester used to manage mid 20s mpg and struggled to achieve 30mpg even at 60mph with cruise control on! It was terrific fun though . . .

 

[Corradobrit]

Swings and roundabouts; the haldex setup is probably more fuel efficient and a "get you out of a sticky spot" type system, but probably less of an impact during driving than say the Subaru Symmetrical AWD which genuinely changed the driving characteristics as it was distributing power more evenly across all the wheels before a change in traction, rather than haldex which I believe is reactive to traction losses. Probably why my forester used to manage mid 20s mpg and struggled to achieve 30mpg even at 60mph with cruise control on! It was terrific fun though . . .

The mpg between Cali FWD and 4Mo isn't so far removed. The simplified and lighter design in the 5th gen system is obviously helping too.

 

[Californication69]

The mpg between Cali FWD and 4Mo isn't so far removed. The simplified and lighter design in the 5th gen system is obviously helping too.

I got 37mpg over 157 miles Monday.
Driving south on M40 & M25
Cruise set at 68mph.
Thought that was nice

 

[WelshGas]

I got 37mpg over 157 miles Monday.
Driving south on M40 & M25
Cruise set at 68mph.
Thought that was nice

With the wind behind you?

 

[Perfectos]

With the wind behind you?

Down hill

 

[Californication69]

With the wind behind you?

Think the wind was northwards on Monday.
But seriously, I was amazed.
It’s just had a service so (shrugs shoulders)

 

[Californication69]

Down hill

Looks like it’s downhill on the map.
Brum to the big smoke

 

[andyinluton]

Ok I have done some further research & agree that VWs own website that suggests its a torsen diff is wrong.

As a penance I have uploaded to the resources area the VW self Study Guides for the T6 transporter & the self study programme for the 4MOTION with Four-wheel Drive Coupling Generation IV

The former document confirms that the T6 transporter is fitted with the 5th generation Haldex unit but uses the control logic of the generation IV.

A couple of pages are shown below, for the whole story you need to download the documents.

 

[Calimili]

+andyinluton you may need to catch up with your unread emails at some point...

 

[Californication69]

Waiting for snow and ice on a car park to see if I can do some nice doughnuts.