[ruzbehxyz]

Originally Posted by dhanushs

Brake locking takes away your control on throttle, and the level of control you get in locked differentials is waayy more. Try driving over huge boulders stretch and you will know.

Point taken. You are right. The only thing I am trying to emphasize is that BTC technology which is part of Traction control, is ever improving.

We’ve also got torque vectoring and it’s only a matter of time before they appear in 4WDs.

And when 4WD EVs come with electric individual-wheel-drive, the lockers will be something of the past.

[shashanka]

Originally Posted by dhanushs

Umm.. Sorry, I would humbly agree to disagree and wouldn't go by an article or online information on the same.

Braking (Reducing torque to a wheel) so that the other wheel gets more torque can never be same as a locked differential. May be for overlanding/expedition and soft offroading it works seamlessly, but in hardcore off-roading the concept of braking for traction will get you laughs.

Brake locking takes away your control on throttle, and the level of control you get in locked differentials is waayy more. Try driving over huge boulders stretch and you will know.


Can you please elaborate on how the sensitivity is reduced?
What are the parameters ECU take into account?
How is it modulated for different terrains?
What is the effect on the driver? (Driver feel)

The importance of locking diffs in serious off-roading (of the rock-climbing kind!) cannot be ignored. And I stay far away from it - tho' the latent desire to take the Thar to the end of Sandakphu is like an itch one can't ignore! However, the system I'm thinking of - realtime response, reliability & durability - will add to the off-roading ability of garden variety enthusiasts like me!

[ruzbehxyz]

Originally Posted by dhanushs

Can you please elaborate on how the sensitivity is reduced?

On many 4WDs when you engage the rear diff lock, the BTC disengages on the front axle. Not in the case of the Ford Endeavour, but the effect is reduced.

The Patrol Y62, Navara NP300, Everest and Ranger PX2 have BTC active with their rear lockers engaged; and yes, it makes a difference.

Source: https://unsealed4x4.com.au/electroni...-differential/

This video from Mr. Robert Pepper will explain it. I have also attended his lectures through Learn Offroad and confirmed the same. Also experimented with my Endeavour.

https://youtu.be/EBG8PBENZ-w

Hear carefully from 3:52 time mark.
This video also highlights the fact that the lockers are better than BTC on steep slopes.

Coming to the question of Why and How this happens is for the automobile engineers to explain, who designed the vehicle or an expert in this systems to answer.

[dhanushs]

Originally Posted by ruzbehxyz

On many 4WDs when you engage the rear diff lock, the BTC disengages on the front axle. Not in the case of the Ford Endeavour, but the effect is reduced.

Even in the very Indian Mahindra Thar, BLD works in the front, pretty well.

This video from Mr. Robert Pepper will explain it. I have also attended his lectures through Learn Offroad and confirmed the same. Also experimented with my Endeavour.

He doesnt explain it. He just says reduced sensitivity.

Originally Posted by shashanka

The importance of locking diffs in serious off-roading (of the rock-climbing kind!) cannot be ignored. And I stay far away from it - tho' the latent desire to take the Thar to the end of Sandakphu is like an itch one can't ignore! ....

Yes, that's exactly the companies are doing. They are making driving in 4x4 very easy, and let the ECU do all the hard work. While I agree it should be the way in mass market SUV's, and suits the purpose.

I just want to make sure that all these 4WD computer aids doesnt really hinder our understanding of basic 4x4 concepts.

[tilt]

Originally Posted by SS-Traveller

The Thar's BLD, or Toyota's A-TRAC system, or for that matter, dhanushs' home-grown system, does exactly that. Equipping all common cars with such a system adds to manufacturing cost, and offers no advantage on tarmac.

Bolding mine. I would love to read more about this. Could you maybe point me to the post please? Much obliged.

Cheers

[ruzbehxyz]

Originally Posted by dhanushs

I just want to make sure that all these 4WD computer aids doesnt really hinder our understanding of basic 4x4 concepts.

Forget computer aids, even 4WD is going to be something of the past. With EVs coming with IWD systems (Individual Wheel Drive) eg. Rivian, locking differentials and many other driver aids will be something of the past. Everything will be ECU controlled except the steering wheel.

[shashanka]

Originally Posted by ruzbehxyz

Forget computer aids, even 4WD is going to be something of the past. With EVs coming with IWD systems (Individual Wheel Drive) eg. Rivian, locking differentials and many other driver aids will be something of the past. Everything will be ECU controlled except the steering wheel.

Just so! And if the ECU does it in an IWD application, is there any reason it can't do the same in AWD/4WD applications. In fact I remember reading quite sometime back about a jugaad in Amsterdam (my Dutch 2nd Officer, also a car nut, gave me the cutting) where an I.C. engine driving an alternator, drove the wheels via motors. The point is, if this was happening 20 years ago, what must be the state-of-the-art today?

[Kosfactor]

Originally Posted by ruzbehxyz

Forget computer aids, even 4WD is going to be something of the past. With EVs coming with IWD systems (Individual Wheel Drive) eg. Rivian, locking differentials and many other driver aids will be something of the past. Everything will be ECU controlled except the steering wheel.

The usual problems of EVs like range and charging time etc are not a problem for the offroad community (Especially USA), they could charge the vehicle and trailer it to the offroad spot, finish the fun and go home.

Its a wonder why EVs have not become mainstream in the offroad scene or even in agriculture like tractors.

[SS-Traveller]

Originally Posted by shashanka

Taking the example of an earlier Mahindra Commander with 4WD and without any add-on frills. If it were to be retro-fitted with such a system today, assuming it was available off-the-shelf, I'd feel that it would add good value to its off-road capability, without huge expense...

Retrofitting such a system will be just a little more complicated than retrofitting an ABS system into a non-ABS vehicle. Do we have any instance of anyone having installed an after-market ABS system in his non-ABS car over here?

Originally Posted by tilt

Bolding mine. I would love to read more about this. Could you maybe point me to the post please?

Look at post #11 in this thread.

[shashanka]

Originally Posted by SS-Traveller

Retrofitting such a system will be just a little more complicated than retrofitting an ABS system into a non-ABS vehicle. Do we have any instance of anyone having installed an after-market ABS system in his non-ABS car over here?

Look at post #11 in this thread.

I'm not sure about an ABS system but I do know of retrofitted steering power-assistance in the Eeco.
And a rudimentary predecessor to the current AMT systems which was being advertised for retrofitting many years ago in the earlier Indian Auto or Auto India (both have folded since), I'm not sure which. The after-market accessories scenario, then and now, don't bear comparison.

However, a brake-assisted slip-limiting system (the kind I envisage) has still not emerged to my knowledge. And when (or rather, if) it does, it should have far wider application as an after market fitment.

We give much less credence to technological hegemony - and its unsavoury ripples - than we should.

[ruzbehxyz]

Originally Posted by shashanka

Just so! And if the ECU does it in an IWD application, is there any reason it can't do the same in AWD/4WD applications.

No it can't because in an AWD/4WD, there is only one motor (the engine), whereas in an IWD, there is an electrical motor for each wheel. The concept is different.

In IWD, each wheel is driven by its own individual electric motor. In addition there is no gear box, no mechanical differentials or lockers and no long and heavy drive shafts.

[shashanka]

Originally Posted by ruzbehxyz

No it can't because in an AWD/4WD, there is only one motor (the engine), whereas in an IWD, there is an electrical motor for each wheel. The concept is different.

In IWD, each wheel is driven by its own individual electric motor. In addition there is no gear box, no mechanical differentials or lockers and no long and heavy drive shafts.

I think we'vw got our wires crossed! The following link (https://www.drivingelectric.com/best...-electric-cars) gives currently available AWD EV's off-the-shelf - from the plebian KIA EV6 up to the exotic Porsche Taycan Cross Turismo.

As I've mentioned before, technology today has taken this kind of high tech within reach of the average guy. Northway Motors (Pune) started a few years ago with their initial offering - a Maruti 800 converted to EV and RWD! So I feel that AWD in an EV is a far simpler affair than an ICE powered AWD/4WD with all its attendant heavy weight hardware/software.

[SukhamritR]

An informative thread explaining the concept very nicely.
Good to have everything compiled in one place.

[ruzbehxyz]

Originally Posted by dhanushs

Yes, that's exactly the companies are doing. They are making driving in 4x4 very easy, and let the ECU do all the hard work. While I agree it should be the way in mass market SUV's, and suits the purpose.

Originally Posted by Kosfactor

The usual problems of EVs like range and charging time etc are not a problem for the offroad community (Especially USA), they could charge the vehicle and trailer it to the offroad spot, finish the fun and go home.

Its a wonder why EVs have not become mainstream in the offroad scene or even in agriculture like tractors.

Originally Posted by ruzbehxyz

Forget computer aids, even 4WD is going to be something of the past. With EVs coming with IWD systems (Individual Wheel Drive) eg. Rivian, locking differentials and many other driver aids will be something of the past. Everything will be ECU controlled except the steering wheel.

Rivian R1S Is the First Production EV to Conquer Rubicon Off-Road Trail.
The Rubicon Trail is one of the hardest, most famous off-road trails in the United States. Hell, Jeep even named its most hardcore Wrangler after it. But it isn't the exclusive domain of Jeeps, as a nearly stock Rivian R1S SUV has become the first production EV to run the gauntlet successfully.

The SUV used for the journey was a quad-motor R1S on the factory 34-inch Pirelli tires, with only light mods to finish the trail. Those consisted of steel rock sliders, front tow hitch receivers, and a roof rack—all fairly basic stuff for managing terrain and recovery.

Read full story here: https://www.thedrive.com/news/rivian...off-road-trail

[Mr.Fawlty]

Starting with the premise of FWD < RWD < AWD < 4x4/4WD, I am hoping to understand the "AWD < 4X4'' part of the argument in a little more detail from the experts and the experienced.

Having recently acquired an avid interest in the theoretical aspects of 4x4-ing, I realise the technicalities and debates around the subject are seemingly endless, and that not all 4x4s are made alike. Things get even more muddy for the uninformed, when commentators chime in with "a 4x4 without MLD is useless." They perhaps are, but scenarios/usecases play a role?

"AWD < 4x4." I find such comparisons being made in the context of two completely different classes of vehicles, with perhaps very different sets of specs and technical feature set. (And I get it, as I don’t think there’s any manufacturer that engineers the same model in both an AWD and 4x4/4WD trims) And then, modern vehicles come with various driving aids - ESC/ESP, traction control, hill descent control, manual diff lockers, LSDs, BLDs, MLDs, and what not - with AWDs leveraging a combination of these to do what they do.

So, I’ve been curious: with all things being equal, in the same conditions and scenarios, would a ‘vanilla’ 4x4 (with no TCS, MLD and other thingamajigs) still fare better than an AWD and be considered more competent? Which would you recommend? When I mean "fare better," I’m suggesting and referring to its capability of aiding the driver to safely negotiate tough and/or low traction sections, mud, slush, ice and snow, steep inclines, rutted jungle trails, shallow water crossings and the likes. No rock climbing or endurance tests intended.

Note to members and mods:
1) I don’t think I could find a similar discussion on these forums, thus the new thread. If one exists, kindly point me to it. Additionally, if the topic isn’t apt for this subforum, please action as appropriate
2) I understand the nature of my query is highly hypothetical, perhaps even vague. If so, and it doesn’t merit a discussion, apologies from a ‘noob’ in advance
3) I understand and acknowledge driving skills and experience matter perhaps even more than equipment, and Altos go where apparently more capable vehicles struggle. Please assume 'moderate' level expertise (one comfortable in a mix of city, highway and rough-road conditions but encountering the situations mentioned for the first time)