AWD intelligent diesel or non-intelligent petrol?

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Originally Posted by RANDLOVER

The drag reduction part (3rd para.) doesn't make sense, unless they mean mechanical drag and not aerodynamic drag.

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Yes - they mean mechanical drag. The entire front drive shaft and front carrier in the diff stops spinning with the front axle free wheeling. They are chasing micro fuel efficiencies.

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Originally Posted by one_iota

I confess to being party to this shemozzle!

As nice intellectually as it would be to know what is going on in the real world does it matter?

I used to drive a Mini Moke. It had winter tread tyres and got me to places that on paper couldn't be gotten to.

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According to Kant Experience without theory is blind, but theory without experience is mere intellectual play. ideally, best to have both, experience backed by explanatory theory ( and vice versa).

We do not live in an ideal world so I guess you often have to make compromises. I don't see this as one of those situations ie the answers are knowable.

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Originally Posted by DavidLew

Hi Thanks for that.

I must say the diagrams and explanations are confusing to me.

"Acts like a differential....fully open clutch with no drive to the front wheels". However, In an open traditional differential there remains torque to the front and rear wheels and indeed split exactly 50:50. Power or "drive" goes to wheels of least resistance ie no traction

" A completely closed clutch with equal torque to the front and rear as with a locked differential" . However, you always get 50:50 torque with an open diff (torque not power/drive - you cannot interchange the terms Power = torque x rpm. No rpm= no power despite infinite torque).

With a locked diff with wheels locked to the same speed (rpm) there exists anywhere between 0 to 100% torque between front and rear. It will only be 50:50 when the the traction on all wheels are the same.

Locked Diff means axles (wheels) spin at same speed and allows for uneven torque split from 0% to 100% between axles and with both torque and power in the same percentage (eg 15% torque will yield 15% power for equal rpm) sent to wheel with most resistance, where it is most needed. Power and drive will result provided the surface allows adequate traction


This video explains open vs closed difs and torque and Power transfer How 4WD Works Part 2 - Open vs. Locked Differentials - Power and Torque Transfer - YouTube
Attachment 185314
So however the system works it is not "like a differential". It may work fantastically well by sending or "vectoring" (torque is a vector) torque to different wheels by whatever mechanism, cluthes.It is theoretically disappointing that only 50% can be maximally sent to the front wheels and if true, the front wheels automatically receive no torque as a priority especially if it cannot be overridden in drive mode selections

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I would suggest it is confusing because JLR are intentionally being vague about the technology.

But it sounds very much like the BorgWarner Torque on Demand system which eliminates the centre differential and replaces it with a clutch pack to drive the front axle.

BorgWarner TOD[emoji768] Transfer Case - YouTube

It acts like a “differential” because it can vary the speeds between the front and rear, but it is not a traditional differential.

It is old technology that was fitted to the Ford Territory with a single speed transfer case, and then to the F-150 with a dual speed transfer case.

BorgWarner Electro-Mechanical On-Demand (EMOD) Transfer Case - YouTube

BorgWarner also have a front axle mounted drive disconnect unit to completely disconnect the front axle.

By the way- it is also possible that JLR are just using marketing BS here to put a new spin on what the Transfer Case Control Module does.

iAWD has a very specific explanation for what it is on the Range Rover and involves new hardware and software, but has no explanation on what it is on the Defender.

Maybe the Defender just gets the “enhanced” software to manage the clutch pack on the centre diff and there has been no change to the mechanical side.

Very strange marketing.

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Originally Posted by DiscoDB

I would suggest it is confusing because JLR are intentionally being vague about the technology.

But it sounds very much like the BorgWarner Torque on Demand system which eliminates the centre differential and replaces it with a clutch pack to drive the front axle.

BorgWarner TOD[emoji768] Transfer Case - YouTube

It acts like a “differential” because it can vary the speeds between the front and rear, but it is not a traditional differential.

It is old technology that was fitted to the Ford Territory with a single speed transfer case, and then to the F-150 with a dual speed transfer case.

BorgWarner Electro-Mechanical On-Demand (EMOD) Transfer Case - YouTube

BorgWarner also have a front axle mounted drive disconnect unit to completely disconnect the front axle.

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Originally Posted by DiscoDB

By the way- it is also possible that JLR are just using marketing BS here to put a new spin on what the Transfer Case Control Module does.

iAWD has a very specific explanation for what it is on the Range Rover and involves new hardware and software, but has no explanation on what it is on the Defender.

Maybe the Defender just gets the “enhanced” software to manage the clutch pack on the centre diff and there has been no change to the mechanical side.

Very strange marketing.

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I would wager you are correct on the marketing spin aspect. A cloud of mystery works well if there has not been genuine innovation.

That Borg-Warner system, now around for many years, does indeed seem clever, "intelligent" even. One of the videos suggested the front wheel spilt is not typically below 20% torque and it senses turning wheels to apportion torque. I think my porsche Macan's "torque vectoring" does something similar and shows a graphical display of torque to front and rear

Anyways, I will try to explore a little further if there is still a difference in the AWD systems between diesel and petrol Defender as this may influence my purchase choice.I'm sure either works well but, a bit like colour, it may come down to little things.

Not sure what the Range rover AWD is or if it carries over to Defender

So found this press release from 2017 which confirms the Range Rover does get the BorgWarner Torque on Demand system.

Enhanced Traction - BorgWarner Transfer Case for Range Rover Velar

The unknown is are they now fitting this to the Defender.

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Originally Posted by DiscoDB

So found this press release from 2017 which confirms the Range Rover does get the BorgWarner Torque on Demand system.

Enhanced Traction - BorgWarner Transfer Case for Range Rover Velar

The unknown is are they now fitting this to the Defender.

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Ah very interesting! Like the videos you linked this article also talks about the "pre-emptive" aspects as well as responding to wheel angles. Not sure if JLR uses this now or some further adaptation that frequently sees front wheel torque at 0% ie RWD.

I found online user and service manuals that refer to workshop manual and with the latter said to explain the AWD system. problem is unable to actually get the said workshop manual.