Modern Vehicle Traction Systems

[XJ Junkie]

Neil, I think you are referring to Quadra-DRIVE II in the Commander. It is basically the same system as the WJ, but with TC added (electronic diff locks as Jeep calls it). This was one of the TC systems I saw rendered useless by mud accumulation on the tone wheels, mentioned in my earlier post.

Quadra-Trac has open diffs (QD has varilock diffs)

Could be. I know they came with a few different variants in the XK. All the ones I’ve seen are also very good.

[ThysleRoux]

When they work they are brilliant, but like most electronic nannies they can malfunction and they can result in the driver becoming overconfident and losing it when the laws of physics are surpassed.

[XJ Junkie]

One of the Commanders didn’t have a centre Lock, which is weird.

[Rabbiddog RIP 7/6/21]

XJ
For dunes we pull the ABS, TC and DSC fuses, use sand mode to kill as much of the electronics as we can.
Disco's are just too heavy for huge dunes.

If you pull ABS or TC at AD in a Disco, you’d get stuck in the car park & I can’t see how sand mode would even work in the absence of those interventions.

At what speed does the sand mode cancel the suspension height?

Sand mode allows a level of wheel spin, but DSC (direction stability control) will still try stop that and every time you turn off the ignition it comes back on.

It will drop at 45Km/h, that's why the guys use different rods on the censors which is a bugger.

I use an electronic lift, I learned a Brakkaduine. I can lift it from 50mm (off road height) to 150mm (fully extended) from standard height.
It does complain but once locked in stays there

[XJ Junkie]

Sand mode allows a level of wheel spin, but DSC (direction stability control) will still try stop that and every time you turn off the ignition it comes back on.

DSC should be able to be deactivated without pulling a fuse. Especially in sand mode. DSC usually cuts power as well.

Sand mode would require the ABS sensors to be operational.

[Rabbiddog RIP 7/6/21]

Sand mode allows a level of wheel spin, but DSC (direction stability control) will still try stop that and every time you turn off the ignition it comes back on.

DSC should be able to be deactivated without pulling a fuse. Especially in sand mode. DSC usually cuts power as well.

Sand mode would require the ABS sensors to be operational.

Correct.

DSC has a button to turn it off, but also has the tendency to turn on when you least expect it, as it re-engages on all settings and engine re-starts.
it's like a bug that wont go away.

[Wooky]

Not driving, or having had any experience with, a vehicle with traction aids this might well be a complete Noob question.
How much does tyre choice and tyre pressures affect the sensitivity / functionality of the TC systems?

Cheers

W

[Mad Manny]

These traction aids work on analysing comparative wheel rotation & applying the brake to that wheel accordingly.
So tyres will have a minimal effect on the system, but may make it kick in microseconds slower if tyres are very large or very deflated...

Why not try attend the Introduction to 4x4 Driving Techniques course on the 30th Wooky ?

[Rabbiddog RIP 7/6/21]

On a D3/4, a partially deflated tyre will will cause the traction control will kick in when taking a sharp corner if taken a bit fast i.e. when you are in a rush.

Otherwise it will stay off.

Not a Noob question, I only found out due to a slow puncture.

[Mad Manny]

On a D3/4, a partially deflated tyre will will cause the traction control will kick in when taking a sharp corner if taken a bit fast i.e. when you are in a rush.

Otherwise it will stay off.

Not a Noob question, I only found out due to a slow puncture.

That's because only one tyre on the axle was soft - I think Wooky was referring to deflating.
As I said, the computer checks for differences in rotation (like ASC/VSC does) & applies the brake accordingly...

[Rabbiddog RIP 7/6/21]

On a D3/4, a partially deflated tyre will will cause the traction control will kick in when taking a sharp corner if taken a bit fast i.e. when you are in a rush.

Otherwise it will stay off.

Not a Noob question, I only found out due to a slow puncture.

That's because only one tyre on the axle was soft - I think Wooky was referring to deflating.
As I said, the computer checks for differences in rotation (like ASC/VSC does) & applies the brake accordingly...

Ahh....ok

Up till +-0.5 bar nothing happens.

On the Eastern cape passes trip, 2 different make's and mileage didn't make a difference

[Wooky]

The question came about after last weekends outing with the Suzuki crowd.
There was a defender 90 puma along for the trip and the driver is very competent and knows his vehicle well.
For all bar one steep rocky incline with two major rock bands to climb up the D90 performed flawlessly and the TC seemed to do what was needed.
On this particular hill the traction control system seemed to really tie itself in knots on what would seem to be a fairly simple obstacle.
It had a bit of a cross axel as you began the second part of the climb and the left front tyre was left hanging for a brief period.
At this point the TC appeared to cut in and out randomly leaving the D90 scrabbling for traction but going no further.

I know the tyres were aired down at the beginning of the trail but as to a partial deflation I am not sure.

So being a scientist at heart the question was more of academic interest as to what could be done / changed to assist in that situation.

My personal preference is for a vehicle without all the electronic aids.
I can see why the vehicle manufacturers fit them and for the vast majority of drivers out there the traction aids are all they want / need.
So really have nothing against them but just prefer to not have them in my own vehicles.

[XJ Junkie]

On a D3/4, a partially deflated tyre will will cause the traction control will kick in when taking a sharp corner if taken a bit fast i.e. when you are in a rush.

That sounds like DSC not TC?

[Rabbiddog RIP 7/6/21]

On a D3/4, a partially deflated tyre will will cause the traction control will kick in when taking a sharp corner if taken a bit fast i.e. when you are in a rush.

That sounds like DSC not TC?

I don't remember the DSC light coming on, but you have a good point. I will test it some time.

On the passes trip we just did and I got the puncture, DSC and TC took over when took the bend on a sand road at around 60km/h

[Martin de Jager]

you want to experience modern against older, this is real action, https://youtu.be/bCJpNQ9M5Qs