Lucky8’s Project Discovery 3

[nwoods]

Okay Lucky8, some questions and comments here for you:

1. Curious, did you try to use hill decent? I am just guessing, but I'll bet you stood on the brake pedal and just slid down the hill, right? Where there any other opportunities to try the hill decent? If you use the cruise control speed buttons, you can dial down the hill decent to be as slow as you want. It's noisy and makes unpleasant vibes as the internal hub mounted pads grab and grind along with the discs, but it does actually work remarkably well when the rate of decent is dialed way down, and it allows you to maintain steering input!

WARNING!

If you leave the car in Mud & Ruts mode, Hill Decent is less effective. Best to use Rock Crawl mode. Here's why:

The SCS ECU applies different HDC control parameters,
depending on the active T.R. Program. For example
it selects the lowest possible target speed for
Rock Crawl. Additionally, the HDC will brake more
aggressively in some Programs but less aggressively
in others, such as for example the low ( Program,
when grip is likely to be limited.

2. Do you know what Mud & Ruts mode does? It changes your gearing, retards your throttle and detunes the traction control. The idea being to reduce wheel spin by reducing high rev'ing horsepower. I'm not a fan of this mode. I'm more of a Good Ole Boy, with high horsepower churning my way through a mudbog with velocity and momentum

Here is LR's write up on the Mud & Ruts Mode programing criteria:

This Program optimises the vehicle for driving on
mud and in deep ruts. The mud may be dry or wet
and slippery. Grip will often be limited and a lot of
axle articulation may be required. There may also be
steep up or downhill conditions and often the vehicle
will be driving in deep ruts, giving rise to specific
issues, such as extreme 'tram lining' or grounding
out. Avoiding wheel spin is not so crucial on mud but
maintaining engine torque is important.

The Program was predominantly tested in the UK,
using forest tracks at various off road facilities.9 <<
A particular dilemma with the development of this
Program concerns two contradictory aims. For driving
in the mud it is beneficial to use engine torque
rather than power and this can be achieved by the
gearbox changing to a higher gear earlier than usual,
thus keeping the engine revs low and in the region
of peak torque. The dilemma with this is that this
reduces engine braking when going downhill. Specific
gearbox strategies had to be developed to find a
compromise.

3. Do you have a rear locker? If so, taking the winch line and attaching it to the front recovery point (way better than the wheel!), while going in reverse will cause the rear end to pirouette around nice and pretty. (Bill Burke taught me that trick).


It seems to me that you still haven't figured out how to use your special program modes to extract the maximum performance. Don't rely on the Easy Button. You've got to think too.

 

[proper4wd]

It's noisy and makes unpleasant vibes as the internal hub mounted pads grab and grind along with the discs

What? There is no such thing as internal hub mounted pads...

The HDC uses a combination of engine braking plus the ABS pump and brake calipers to regulate wheel speed.

 

[brickpaul65]

For nasty mud like that what setting do you recommend?

Grass and snow with traction control off and HDC in Rock crawling mode?

I am just curious in how to use the tools at hand better. I am a newbie to off roading and the LR3 is my first vehicle for the task. So I don't always know the best approach and what settings to use to allow the vehicle to perform that approach (e.g. allowing wheel spin etc.).

Thanks!

*edit* I realize this advice may differ if you are actually present and the vehicle or obstacle is different then expected. I am just wondering what I would use to accomplish that approach.

 

[JAK]

The rear disc brakes have an internal drum brake typically used for the parking brake. I did not know that they were used for HDC control though.

 

[proper4wd]

The rear disc brakes have an internal drum brake typically used for the parking brake. I did not know that they were used for HDC control though.

It is not. That's a separate system actuated by an electric motor that "pulls" on two cables to actuate the brake shoes.

 

[LR Max]

Oh and you can't drive these trucks like you would, say, a 1980 Chevy pickup in the mud. You can't just punch it and go nuts with the throttle. Gotta work with the traction control. Totally different way or driving.

I also an interested in knowing how well the truck performs in the different modes. For me, I'd just put it in rock crawl and go.

 

[JAK]

It is not. That's a separate system actuated by an electric motor that "pulls" on two cables to actuate the brake shoes.

That was my understanding, I have no idea what nwoods is saying about the internally mounted pads then.

My impression from Lucky8 was that this was not really a hill and that the truck slid down an incline within a few seconds. The pictures of the mud in the tires tell the whole story, might as well have been ice.

 

[nwoods]

It is not. That's a separate system actuated by an electric motor that "pulls" on two cables to actuate the brake shoes.

Hmmm.. I am not sure about that. I think it's definitely involved in the hill decent system. But I can't prove it. So agree to disagree until proven otherwise.

My impression from Lucky8 was that this was not really a hill and that the truck slid down an incline within a few seconds. The pictures of the mud in the tires tell the whole story, might as well have been ice.

Agreed, that is why I asked he had an opportunity to test it later on. Who knows? Ohio is pretty flat

 

[proper4wd]

http://topix.landrover.jlrext.com/topix/service/archive/65295/hill descent control (hdc).pdf

It's strictly a function of the ABS system. Think of it like traction control. The ABS pump pulses the brakes on individual wheels to maintain steady wheelspeed. The Electronic Parking Brake (EPB) is not designed to nor can it operate quickly enough to be effective in this capacity.

This is first hand knowledge from Land Rover tech training.

 

[nwoods]

Adam, this is not a topic I want to invest a lot of time or energy into, but I read that excerpt of the Owner's Manual, and note that is says a few things that leave some room for discussion:
1. "Hill Descent Control (HDC) operates in conjunction with the anti-lock braking system" In Conjunction does not mean solely uses the ABS system.
2. "...you can select HDC permanently to ensure that control is maintained. ABS and traction control are still operational." How can you have ABS on, with HDC engaged? Doesn't one rule out the other?

Lastly, in operation, HDC feels nothing like ABS. I have trigged both modes numerous times, and they are starkly and distinctly different in feel and sound. It could very well be the same exact components, but it sure doesn't feel that way.

Either way, I am happy to be wrong. I don't really care. I wish I still had an LR3.

Now, post the rest of your story!

 

[proper4wd]

Don't mean to start an argument with you Nathan,

HDC/ABS/TC is the same reactionary system (ABS pump/module pulsing brakes) to 3 different conditions.

ABS modulates brake pressure during braking

TC modulates brake pressure during acceleration/under power

HDC modulates brake pressure during coast

The end goal is always the same - keep all four wheels turning at the same speed.

They all co-exist in the same infrastructure because no two conditions ever overlap.

 

[nwoods]

That's a fantastically concise and effective explanation. Very cool. Thanks.

Now proceed with the rest of the story!

 

[srschick]

1. Curious, did you try to use hill decent? I am just guessing, but I'll bet you stood on the brake pedal and just slid down the hill, right? Where there any other opportunities to try the hill decent? If you use the cruise control speed buttons, you can dial down the hill decent to be as slow as you want. It's noisy and makes unpleasant vibes as the internal hub mounted pads grab and grind along with the discs, but it does actually work remarkably well when the rate of decent is dialed way down, and it allows you to maintain steering input!

so, with HDC engaged, one can increase/decrease the rate of hill decent with the +/- cruise control buttons?
learn something new every day...

 

[morrisdl]

This has been my new leaning of the day a couple times. It would be nice if it pops a reminder message about this on the dash when HDC is engaged.

I'm sure there are some great *oh crap* decents where HDC is super helpful, but I haven't really every needed and more often feel like it's inadvertently activated and burning up brake pads 10X faster than my foot.

The lr3 transmission does great holding the whale back on long decents. I use my brakes 1/2 as often as the defenders I follow around.

 

[zelatore]

Somebody needs to channel Paul Harvey.

We need 'the rest of the story'