Four wheel drive

[c1181427]

Nothing to do with the AWD system im afraid as it doesn't report anything like that. It'll be the 2nd gear gear change indicator or the '2' next to the secondary fuel consumption readout as a guess!

The number 2 was in the box below the gear indicator and much smaller in size too...what should the 4wd drive symbol look like then?

I wonder what that number was then.. :/

[Yeti_Man]

The number 2 was in the box below the gear indicator and much smaller in size too...what should the 4wd drive symbol look like then?

I wonder what that number was then.. :/

As I said - there isn't a 4wd symbol. It'll be the fuel consumption setting as I mentioned above.

[c1181427]

As I said - there isn't a 4wd symbol. It'll be the fuel consumption setting as I mentioned above.

Thanks

Funny there is nothing notifying you the car is running on 4 wheels though

[Yeti_Man]

Thanks

Funny there is nothing notifying you the car is running on 4 wheels though

Very few haldex equipped cars on the market report anything back to the driver as to what the system is doing.

[c1181427]

Very few haldex equipped cars on the market report anything back to the driver as to what the system is doing.

Thanks Learn something new everyday

[ejstubbs]

Funny there is nothing notifying you the car is running on 4 wheels though

 

The lack of horrendous screeching noises from the underside is what tells you that the car is running of four wheels (as opposed to three or fewer).

 

The Haldex is not an on/off switch: it varies the amount of drive going to the rear wheels according to what it can work out from the signals the sensors provide about how the wheels are behaving, driver control inputs etc.  (ISTR that in the "steady state" it sends 5% torque to the rear, but I may be mistaken.)  So if there was a light, at what point would you expect it to come on?  And what would you do about it when it did?

 

It might be easier to think of the Haldex as being similar to other permanent 4WD systems like Subaru's, or Audi's torsen-based system.  It's just that Haldex relises exclusively on electrickery to manage the torque distribution whereas those other systems are basically mechanical (though no doubt with some electro-magical fiddle-aboutery involved these days).

 

a second or so of clear wheel speed difference between front and rear wheels should have the Haldex system putting more power to the rear automatically

 

It's been asserted many times on this forum (probably with documentary references in evidence) that the Haldex fitted to the Yeti can detect wheelspin within less than a single revolution of the front wheels, so it shouldn't even take as long as that.  (I believe it was established in the 'Haldex failure scare' thread that, when pulling away from rest, the Haldex is fully engaged - so, at a guess, 50% of torque going to the rear?)

[JCP]

The idea of the Haldex system is just to automatically and unobtrusively ensure their is always the most grip the tyres can give. Older systems with various knobs and levers and on my 1990 Vitara manual free-wheel hubs-you had to get out of the car and re-set them!!- all gave people things to do and gave them an illusion of control. A yeti just does what is required. Those who used to do all their own controls only rarely achieved the best from them-those with real expertise have always been a small proportion of users. I wonder why anyone would think it beneficial to have a display to tell them what a fully automatic system is doing? Some older Japanese vehicles had all sorts of extraneous instruments inclinometers/altimeters etc which must have amused some people.

[Huskoda]

All versions of Haldex used in Yetis also preemptively lock based on throttle input etc so you shouldn't really notice any changes. It would be nice though to have a switch that changed the system between Lock/Auto/Off like other manufacturers offer with similar systems.

 

My Subaru has a screen you can switch to that shows you exactly what the AWD system is doing, showing which tyres have traction and where the power is being fed to and how much plus which way your front wheels are turned, but if I'm in a situation it would show anything interesting, I'm busy looking where I'm going instead

[ejstubbs]

All versions of Haldex used in Yetis also preemptively lock based on throttle input

 

Can you expand on that - do you mean that, if you floor the loud pedal, the Haldex will send drive to the rear wheels without waiting for the front wheels to spin?  That sounds like a sensible approach.  It's probably documented in one or more of the various references which have been posted on threads in this forum but I can't actually remember reading about it before.

[Ryeman]

It's hard to think of an Asian manufacturer that DOESN'T like 'arcade game' read outs .

Their club meets tend to be at 2 or 3 in the morning otherwise they spend most of their time crawling in traffic and amusing themselves with the dash display.

[Llanigraham]

EDIT,

 

Already answered but.........

 

 

R T F H !! 

[Huskoda]

Can you expand on that - do you mean that, if you floor the loud pedal, the Haldex will send drive to the rear wheels without waiting for the front wheels to spin?  That sounds like a sensible approach.  It's probably documented in one or more of the various references which have been posted on threads in this forum but I can't actually remember reading about it before.

 

Yep, thats just one example. Haldex 5 in FL Yetis also uses the inclination sensor and will send more power backwards when you're driving up hill. The balance is more towards the back if you're towing too. V4 may also do this, but I'm not sure. Its a pretty clever system.

[Llanigraham]

V4 does it too.

[muddyboots]

Can you expand on that - do you mean that, if you floor the loud pedal, the Haldex will send drive to the rear wheels without waiting for the front wheels to spin?  That sounds like a sensible approach.  It's probably documented in one or more of the various references which have been posted on threads in this forum but I can't actually remember reading about it before.

 

Yes, that and some other scenarios are described in the Haldex Gen 4 Self Study guide (written for the Tiguan, but assume it's the same system).

 

See pages 19 and 20, here:

http://www.freel2.com/gallery/albums/userpics/11383/tiguan_haldex_gen4.pdf

[muddyboots]

V4 does it too.

Does it ?

 

There's no reference in the list of sensor inputs to an inclination sensor, or any reference to hill/towing scenarios, in the Gen 4 self-study guide (that I can see).

[ashtree]

The lack of horrendous screeching noises from the underside is what tells you that the car is running of four wheels (as opposed to three or fewer).

 

 

Members of a certain age may remember "Three wheels on my wagon" by the New Christy Minstrels which charted the progressive loss of wheels from said wagon.  Quite impressively, it still managed to move on one wheel.  Beat that, Haldex!!

[Llanigraham]

Does it ?

 

There's no reference in the list of sensor inputs to an inclination sensor, or any reference to hill/towing scenarios, in the Gen 4 self-study guide (that I can see).

 

4 years and 88k miles experience says it is pre-emptive.

[crazyj]

It probably wouldn't take any extra components for the Yeti to deduce its under this kind of load, the Haldex already knows the torque required, the throttle position, road speed, lat and long acceleration and yaw. It would only need a software tweak for it to know if it's going uphill or towing...

The ecu will know it its towing....

The headlight levelling system knows the cars inclination...the TCS may gather that data too....

.....seen a discussion on vw vortex that the R32 may use the data from that.

Clever wee beastie.

Just thoughts.

J

Edited 22 January, 2015 by crazyj

[Totally Square]

EDIT,

 

Already answered but.........

 

 

R T F H !! 

What Headline?

(Had to look up RTFH - I usually only see RTFM... ;-) )

[Wardy]

Anyone seen a Haldex 5 technical document anywhere? I see a link to the V4 information, but would be good to see a newer revision.

[yetiscot]

Anyone seen a Haldex 5 technical document anywhere? I see a link to the V4 information, but would be good to see a newer revision.

What about this?

http://www.borgwarner.com/en/Haldex-AWD/products/Literature/Borg%20-%20Haldex%20GenV%20Sheet%20Europe%20PRINT%206-11.pdf

[Wardy]

Yep, bit light though as that's the Product Sheet - but that sort of thing yes.

[muddyboots]

4 years and 88k miles experience says it is pre-emptive.

Yes we know Gen 4 is pre-emptive, it's one of the main advances compared to earlier versions, and the various scenarios where this happens are explained in the self study guide.

 

But you suggested that -  similar to the Gen 5 that Huskoda describes - Gen 4 also takes input from an inclination sensor and uses this (plus towing knowledge) in the same way.

However the SSG doesn't show such a sensor as one of the numerous inputs.

So I was wondering how you know - have you got a tech guide somewhere that shows it ? 

If not, how do you know the behaviour you've experienced is down to input from an inclination sensor and/or towing input, and not just the normal pre-emptive behaviour of the Gen 4  ?

 

Just curious that's all, I like to know details of how stuff works

Years ago I paid for a copy of an ESP self study guide from ErWin, as I was having issues on a previous car - the ESP always disabled exactly 10 mins into a journey. Only fault reported via VCDS was an alternator wiring issue. The guide showed that among the many sensor inputs to the ESP system, was - lo and behold - a load signal taken off the alternator. Sure enough I traced and found a broken wire in the alternator loom. Fixed that, and the ESP worked again. Dealers didn't have a clue. So I think the self study guides are generally pretty accurate.

[crazyj]

For my part it is pure speculation. There is similar speculation all over the VAG community about the Haldex ...some plausible and some erm...a bit nuts.

I have little experience with mucking about with modern cars ( though no stranger to other selected modern technical gubbinses) and have enjoyed reading the self study guide..amazing stuff.

I think it is a safe bet that the cars evolve faster than the printed learning materials are updated and I think the system components and software (and potentially the sensor matrix) will be updated throughout the production run of a particular Haldex generation.. Would be interested to see a later issue of the linked self study guide.

Worth noting also VAG tend to be a bit tight lipped. An example of their tacit nature Is to see how hard it is (thread on this forum) to get details of their screenwash!

I am still enjoying speculating and learning about the yeti with the help of you guys... when I bought it I didn't anticipate a whole new hobby.

Cheers

J

Edited 23 January, 2015 by crazyj

[muddyboots]

So, this morning I looked out at my driveway that is now covered in a thick layer of polished ice, and the nerd in me thought...hmm, time to video the 4wd system in action.

 

I can confirm it's definitely pre-emptive  or at least reacts damn quickly.

No delay what-so-ever sending drive to the rear when pulling away on ice.

I could also hear the ABS module working hard, so the EDL was obviously doing its thing too.

 

If I can find the time, I'll stick the video up somewhere.