Climbing a snow packed hill

[lionvt]

We have a 05 LR3. We live on a challenging class IV road. Over all, the LR3 has been great. However, there seems to be one major weakness:

you cannot spin the tires when you need to to dig to traction while climbing a snow packed hill.

Last week (winter comes early here) I had another example. 6" of fresh greasy snow. Admittedly, I do not have the snow tires on this vehicle yet (but I have had the same trouble with snow tires). As traction begins to slip and the snow compacts to ice under the tires, the vehicle progressively slows each wheel (controlling wheel spin) until (once all 4 tires are on an ice patch) -- the vehicle stops on the hill. Even under full throttle it will only slowly spin the tires which won't really "dig" -- even with studded snow tires.

I have a 95 Disco I and a 91 Rangie. On these vehicles under similar circumstances, no big deal -- you can stay on the accelerator and saw the wheel back and forth (mindful of the direction in case the tires suddenly bite) until you "dig" down to the gravel road.

I can't seem to find a mode that allows me to do this. Admittedly, my real world "experiments" were all under less than ideal conditions (stuck on a snowy hillside in a blizzard, etc.) but I've tried in 4low, "snow" mode, "rock" mode and with all traction profiles off. This is my wife's vehicle so I don't drive it everyday and am not 100% familiar with it.

Is there anyway to do this? Basically, I would like to turn off the anti-slip features so I can get some old fashioned wheel spinning?

I would like to keep the vehicle stock so I am really looking for strategies (or the secret) do doing this with a stock vehicle.

Thanks.

Will

 

[jimbiram]

Try turning off the DSC. It should help with that.

 

[nwoods]

Right, turn off DSC and try the mud setting also.

 

[garrett]

Wheel spin is what you DON'T want. That's why traction control sucks in most places. In order for traction control to work you need wheel spin. What you don't need in snow.
Having better throttle and brake modulation/control is a better option.

 

[sideview]

The idiot dial is pretty self explanatory for common conditions, but understanding a bit about the effects the different settings have on throttle response, transmission, etc., will help you use it to its potential. Each situation is different and sometimes the best settings aren't the obvious.

DSC can kill power and momentum when you really need it, like the others say, could be good to shut it off. I usually manually shift too, rather than let TR handle it (just a preference).


Doubtful it's all-inclusive but here's a basic lowdown of the different settings.

- grass/gravel/snow, diffs will lock, transmission upshifts early starting in H2 or L3, and throttle response retarded to help avoid wheel spin and too much power to the driven wheel when accelerating, DSC aggressive to limit slip.

- mud and ruts, transmission upshifts early, and diffs will partially lock for better traction, DSC normal or aggressive I'm not positive.

- rock crawl, the diffs lock, throttle response is slow starting in L1, DSC aggressive to limit slip.

- sand, quick throttle response, downshifts early, DSC reduced to allow slip.


Sometimes just keeping it in normal is good, turn off TR & DSC, put it in low range and give it a go with a little foot action. Look at the situation first and determine what would be most helpful. After you play around with it a while, you'll get a feel for it.


Putting on the snow tires will definitely help too

 

[LRflip]

Tami, you are such a fox.

 

[garrett]

The idiot dial is pretty self explanatory for common conditions, but understanding a bit about the effects the different settings have on throttle response, transmission, etc., will help you use it to its potential. Each situation is different and sometimes the best settings aren't the obvious.

DSC can kill power and momentum when you really need it, like the others say, could be good to shut it off. I usually manually shift too, rather than let TR handle it (just a preference).


Doubtful it's all-inclusive but here's a basic lowdown of the different settings.

- grass/gravel/snow, diffs will lock, transmission upshifts early starting in H2 or L3, and throttle response retarded to help avoid wheel spin and too much power to the driven wheel when accelerating, DSC aggressive to limit slip.

- mud and ruts, transmission upshifts early, and diffs will partially lock for better traction, DSC normal or aggressive I'm not positive.

- rock crawl, the diffs lock, throttle response is slow starting in L1, DSC aggressive to limit slip.

- sand, quick throttle response, downshifts early, DSC reduced to allow slip.


Sometimes just keeping it in normal is good, turn off TR & DSC, put it in low range and give it a go with a little foot action. Look at the situation first and determine what would be most helpful. After you play around with it a while, you'll get a feel for it.


Putting on the snow tires will definitely help too

Most of that sounds good, but the only part I don't like is the diffs locking in snow and mud. I hate giving control over to a computer in any case, but having diffs locked in snow and mud on any kind of side slope is bad ju ju.

That is one (of many) things that they fucked up with the Land Rovers (DIs, RRCs, etc). You can't "lock out" first gear. How easy would that have been and makes life a lot easier in snow and other conditions.

In sand you don't want early downshifts though. You want to prolong the downshifts as much as you can. That's why you start off with momentum/speed at the bottom and come away from the throttle as you begin you assent. Coming away because you don't want to downshift and keep as little power going to the ground as possible.

Ok I am getting picky now.

 

[sideview]

Tami, you are such a fox.

Haha!


Yeah I don't fully understand why the diffs lock in snow & mud either. The diff locks aren't either "opened" or "locked", they call them "progressive" ...supposedly this gives them a greater/lesser degree of locking based on the selected TR parameters, and will automagically lock as required (however it figures when that is). The lock is active in snow and mud, but not to the degree as in rock crawl.

On one hand whatever magic its doing works great, on the other hand it?s kind of scary to have it fully controlled by the puter. It'd really be nice to have a manual override for the diff.

I'm not too schooled on sand driving TBH. Had a bit of sand in FL here & there but nothing EXTREME lol. The west coasters will know better about those settings prolly.

 

[LRflip]

Dont tell Dan I said that....

 

[nwoods]

Tami, those settings you posted are not quite correct. I don't have time to go into detail, but mud/ruts the shift points are lower (keeps RPM's up, DSC sensitivity is reduced, and traction control is reduced, but so is throttle response (it's less responsive)

Sand is similar, but the throttle response is retarded only at take off, and it will want to start in a higher gear, but once you are moving, it completely changes and makes the shift points lower, and increases throttle responsiveness, and almost completely disengages traction control and DSC. Sand most is the most fun if you are looking to create a rooster tail on the trail or kick the truck into a nice 4 wheel throttle steering slide.

Grass/Gravel/Snow is the most mellow setting, with higher shift points, higher gear starts, much more sluggish throttle response, hyperactive DSC and over eager traction control settings.

Rock crawl is similar, except for lower gear, with a bit higher rpm's and much more sensitive traction control. I can't for the life of me remember what DSC does in Rock Crawl, because I always turn it off.

Garret, as for snow, there are several effective techniques for snow, it just depends on the conditions. It's been a while for me, but I grew up in Michigan and got plenty of snow miles under my belt. I used to love taking an old Suburban 4x4 out onto the lakes and make giant doughnuts and half a mile long power slides. Sucks when you hit a plug left over from an ice fishing hole though!

 

[MUSKYMAN]

higher shift points and snow do not go together

then again letting a computer decide anything off road is kinda lame.

we really need to do a bonafide snow rally some day...that would be a good time for sure

 

[sideview]

we really need to do a bonafide snow rally some day...that would be a good time for sure

Definately, that would be fun I'd love to go to the Winter Romp. Hope we at least get some legitimate white stuff here this year.

Thanks for expanding on it Nathan.

 

[Captainruss]

Definately, that would be fun I'd love to go to the Winter Romp. Hope we at least get some legitimate white stuff here this year.

Thanks for expanding on it Nathan.

You should! We come down there for MAR and stuff, it's time you guys make the ride north for Winter Romp. If anything, it is a great social event and you'll get to meet some of the northeast folks and even a few Canadians, ack: ).

So the LR3 has no way of just dropping it in low and going to a manual mode and using brake modulation like on DII's? That's awful. I knew LR was getting away from useful off-road vehicles but that is ridiculous.

 

[garrett]

Sand is similar, but the throttle response is retarded only at take off, and it will want to start in a higher gear, but once you are moving, it completely changes and makes the shift points lower, and increases throttle responsiveness, and almost completely disengages traction control and DSC. Sand most is the most fun if you are looking to create a rooster tail on the trail or kick the truck into a nice 4 wheel throttle steering slide.

This is counter productive. Starting in a higher gear is correct, but the shift points should not be lower. To me that means shifting sooner in each gear and that is what you don't want. Again you want the truck to stay in the highest gear for the longest period of time. Less power to the ground. Just like walking in sand/snow. You want to "push" as softly as possible. That is unless the truck is trying to get to the highest gear and stay there for a longer period reducing the potential to downshift.

This is where the automatic is a far more predictable and an easier vehicle to drive than a manual.

This works the same with snow. You don't want power to the ground, so you increase your gear to reduce the power. Hence the reason so many vehicles have a 1st gear cut out, so the vehicle starts in second. All it would have taken was a damn button. You want those shift points to happen quickly in order to get to the highest gear and then start coming away from the throttle to keep it that gear.

It's show much easier to demonstrate this in person, rather than talking about it. It's not always so black and white though.

 

[MUSKYMAN]

the problem with higher shift points is that it then allows the engine to get into its power range and that makes it easier to break traction.

 

[umbertob]

This is a section off a Terrain Response presentation made by LR's engineering at a 4x4 conference a few years ago, when they first introduced the system in the Disco/LR3. It's obviously not very rich in technical details (I guess they didn't want to give away the farm...), but I find it interesting anyway, as it details the various modes, what they were trying to achieve with each, and what challenges they were confronted with when their theories were tested on an actual off-road course.

The Terrain Response system was extensively developed in a wide range of conditions. It was tested from the frozen lakes of Northern Sweden to the hot sand deserts of South Africa. Testing often involved multiple disciplines, such as engine, gearbox and traction experts, as well as Terrain Response Team members.
Two key attributes that were to be improved via Terrain Response, were traction and more particularly 'composure'. Both these attributes, and especially composure, are very difficult to measure or assess objectively. This makes it difficult to prove that development progress is being made, or how good the off road performance of the final system is. However, the development of Terrain Response has been carried out by engineers with considerable off road experience, who were able to use methods of subjective performance assessments, in a relatively systematic and objective way.

General Program
In this setting the systems will function generally as on vehicles without Terrain Response, using thresholds that give a general compromise optimised for all conditions, and in particular for on-road behaviour, The vehicle will still perform admirably well in severe off road conditions, even when used in the general program. All systems respond to the prevailing conditions, but can not anticipate them based on the Terrain Response program. It is of course this anticipation of prevailing conditions that provides some of the benefits when the special Programs are used.
The 'General Program' compromise can be different than that developed for non-T.R. vehicles, because on T.R. equipped vehicles the General Program compromise does not need to cover the most extreme conditions and may not need to be as compromised as otherwise, since these extreme conditions are better covered by the appropriate T.R. special Programs.

Grass-Gravel-Snow
In this setting the individual systems revert to control software which optimises the sub-system, and thus the vehicle traction, handling and driveability, for low μ conditions. When driving on ice or wet grass it is particularly important to avoid wheel spin when driving off, because any wheel spin will change the surface, and reduce traction below the original low level.
The Program was specifically tested under low ( conditions in Northern Sweden, both on frozen lakes as well as on inclines. Particular emphasis in this Program is on modifying the powertrain torque delivery and avoiding wheel spin, by applying torque to the wheels gradually and by sensitising the traction systems. In addition to Northern Sweden this Program was also tested on gravel surfaces in both the UK and Belgium and on grass.

Mud-Ruts
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.
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.

6.4 Sand
This Program optimises the vehicle for driving on sand. The Program is optimised specifically for deep and soft sand, which is often also very fine, and which is typically found in deserts. This Program was almost entirely developed outside the UK and work was carried out on three different continents. Desert and sand dune areas in the USA, South Africa and the Middle East (Dubai) were used.
Sand provides quite reasonable levels of grip but any wheel spin causes a vehicle to sink into it, and therefore all systems aim for a cautious take off. Otherwise, driving on sand causes a high resistance and a lot of power is required to make progress. The engine and gearbox need to combine to maximise the power whilst for example the DSC (dynamic stability control) system must try and avoid any power reduction requests.
The main issue with the Sand Program concerned the dilemma of avoiding engine torque reductions when driving in the sand, versus the requirement for the DSC calibration to still give an acceptable vehicle handling when the Sand Program is used inappropriately on the road, or on a low ( surface. It proved that mere calibration differences in the DSC algorithm were not sufficient to achieve the desired reduction in engine intervention. Specific DSC logic had to be developed to achieve this.
Other issues were caused by characteristic sand corrugations which caused a very typical wheel bounce. This initially confused the DSC system.
A further issue concerned the requirement for the vehicle to meet stringent emissions legislation, in all high range T.R. Programs. This meant that some compromises had to be made in for example the transmission calibration.

6.5 Rock Crawl
This Program optimises the vehicle for driving over big rocks or boulders or other unyielding obstacles. Such obstacles often require extremes of axle articulation, causing wheels to be unloaded or to lift off the ground, causing a risk of them spinning up.
The rocks or boulders may only provide limited grip, particularly if covered in dust or mud. The extreme conditions make it important that progress is carefully controlled and slow. The Rock Crawl settings are selectable only when in low range. It must be made easy to edge a vehicle over the obstacles by careful modulation of the throttle. Torque at the wheels must build up carefully to slowly climb obstacles, but reduce quickly as the obstacle is scaled, to avoid overshooting. In order to improve grip and vehicle composure it is important to avoid wheel spin as much as possible. Particularly when wheels may be up against steep obstacles and the vehicle is also going up a steep incline, it is essential that any sub-system torque reduction requests (e.g. from DSC) are minimised and that torque at the wheels is maximised by providing the lowest gearing possible.
This Program was developed in the USA and in the UK. Specific issues in this Program concern the extremely low vehicle speeds, which give a very low resolution of the wheel speed signals used by the T.R. sub-systems.

 

[sideview]

You should! We come down there for MAR and stuff, it's time you guys make the ride north for Winter Romp. If anything, it is a great social event and you'll get to meet some of the northeast folks and even a few Canadians, ack: ).

So the LR3 has no way of just dropping it in low and going to a manual mode and using brake modulation like on DII's? That's awful. I knew LR was getting away from useful off-road vehicles but that is ridiculous.

Will have to see, would absolutely love to (even with the Canadians lol), time & money ya know blah blah...

Nah, you don't have to use TR in the LR3. But there's no way to manually lock diffs.

 

[sideview]

It's show much easier to demonstrate this in person, rather than talking about it. It's not always so black and white though.

Well let's go hit some trails and show me then! Interesting stuff, I learn so much from you guys...and still have so much to learn. At the risk of sounding like a bubblehead, I'm not sure what it means that 1st gear is cut out? Do you mean you can't drive in 1st?

 

[gordonwh]

You can simply use the manual shifts to change the shift pattern in a particular TR setting, if you don't like LR's choice. If you do this in sand mode with DSC off, you're essentially completely "manual" - minimal traction control and your choice of shift points.

You can take off in L2 (or L3) and as you start moving, select 3 (or 2) upshifts in rapid succession and the box will change up as soon as it can and you'll be in a higher gear at low revs (max torque) asap.

Cheers,

Gordon

 

[garrett]

Well let's go hit some trails and show me then! Interesting stuff, I learn so much from you guys...and still have so much to learn. At the risk of sounding like a bubblehead, I'm not sure what it means that 1st gear is cut out? Do you mean you can't drive in 1st?

1st gear "lock out" means that a vehicle will not start in 1st, but rather 2nd gear. Many cars have a winter mode that does the same thing to minimize wheel spin. Toyotas had them in the FJ80s. It's a nice little button to have.