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Old 25th August 2013, 19:59   #211
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Default Re: Driving all four wheels: how is it done?

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Originally Posted by .anshuman View Post
Invincible? Nowhere near it! This pretty much soft roading stuff, show me where they need M/T tires or extra articulation or Low range. Any crossover with AWD and decent GC will do it.
Thanks for those videos, awesome stuff, unbelievable, going through some more.

You are right, and that's what I meant too, saying it depends on the driver and his luck as well,
but what I also meant to portray is, at most, this is what 90% of the users out there may want to subject their cars to 10% of the times, occasionally, either deliberately or accidentally.
Just was kind of answering my own earlier question on how competent an AWD is and whether it was just a marketing term, it depends, I should say.

What I also noted is that these extreme 4x4's are monsters, I mean even with all those drive-train advantages, they rely heavily on their monstrous engines, most 3.5L, 4.0L & above, so power too does give them that invincibility.

I think that's why modded Gypsy's is best here, apart from the mechanical modifications it also has metal bumpers, good thing as at least it wont break.
A 4x4 with all the mods like you mentioned will need a dedicated extreme off road event calender, to make use of its potential, but I believe off roading events hasn't reached that level in India both due to expenses and planning, the middle class majority can't afford both due to other challenges.
Also does one have to replace an open differential to fit a lockable differential or is it something that can be modified and make the open differential adapted to, like taking eg. front differential of Safari 4x4.

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Old 26th August 2013, 09:46   #212
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Default Re: Driving all four wheels: how is it done?

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Like I said - the Middle-Eastern & South African websites mention existence of Torsen - find me a mention of Torsen in a 5-speed MT Fortuner from an Indian or Far-Eastern countries' website/brochure/owner's manual/workshop manual.
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They can't remove LSD from a fulltime 4WD. Guess what happens if you have an open center diff?
Explained here: http://www.team-bhp.com/forum/offici...ml#post2488854
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4WD with open center diff is only useful on tarmac, this is because if one wheel is slipping, all the remaining wheels lose power. Not really useful off the road. Therefore, it is rarely offered.
The first generation Range Rover, for the first 18 years or so, came with an open centre diff (despite which, it had exemplary off-road performance); this was followed by a viscous automatic locking centre diff for another 14-15 years. Torsen made its first appearance in the Range Rover in 2003, till 2007, when electronics took over and a mechanical centre LSD became redundant.

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Old 26th August 2013, 10:03   #213
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Default Re: Driving all four wheels: how is it done?

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Like I said - the Middle-Eastern & South African websites mention existence of Torsen - find me a mention of Torsen in a 5-speed MT Fortuner from an Indian or Far-Eastern countries' website/brochure/owner's manual/workshop manual.
As a programmer, I can use logical deduction.

1) First find out if the Indian Fortuner has LSD. Very easy to find out. Park the Fortuner on a level ground, and raise one wheel off the ground using a jack. Now start the vehicle and try to the move it. If Fortuner doesn't have center LSD, it can't move at all. If it moves, it has center LSD. I am sure some of our Fortuner owners will oblige with this test.

2) If the Fortuner has LSD, is there any reason why they will use a different LSD than used in Middle East or Africa? Don't see why they should use viscous coupling or clutch type LSD just for South Asia market.

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The first generation Range Rover, for the first 18 years or so, came with an open centre diff (despite which, it had exemplary off-road performance); this was followed by a viscous automatic locking centre diff for another 14-15 years.
As I said, it is rarely offered. Hopefully, they also provided manual diff locks, if not the 4WD will be worthless on slippery ground.
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Old 26th August 2013, 10:10   #214
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Default Re: Driving all four wheels: how is it done?

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Originally Posted by Samurai View Post
First find out if the Indian Fortuner has LSD. Very easy to find out. Park the Fortuner on a level ground, and raise one wheel off the ground using a jack. Now start the vehicle and try to the move it. If Fortuner doesn't have center LSD, it can't move at all. If it moves, it has center LSD. I am sure some of our Fortuner owners will oblige with this test.
Disagree. A Torsen cannot move a car with one wheel needing almost zero torque to rotate it. One wheel in air means a Torsen diff equipped vehicle will behave exactly like an open diff vehicle, i.e. simply spin the wheel in the air without transferring enough torque to other wheels to move the vehicle.

(EDIT: You could easily check this on your GV itself - jack up one wheel, and see if the car moves without engaging centre diff lock, or 4HL mode)
Quote:
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...is there any reason why they will use a different LSD...
Different LSD? The question is whether the Indian Fortuner has an LSD at all - or is it an open diff? If LSD, logically (as you explained), it should be Torsen.
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Hopefully, they also provided manual diff locks...
Much simpler engineering, and always provided in Rangies since the beginning. Unrelated to LSD. Had a separate shift lever to lock the diff. Later models used engine vacuum IIRC to engage the lock (so a running engine was a pre-requisite for locking the centre diff).

Last edited by SS-Traveller : 26th August 2013 at 10:32.
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Old 26th August 2013, 10:31   #215
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Default Re: Driving all four wheels: how is it done?

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Originally Posted by SS-Traveller View Post
Disagree. A Torsen cannot move a car with one wheel needing almost zero torque to rotate it. One wheel in air means a Torsen diff equipped vehicle will behave exactly like an open diff vehicle, i.e. simply spin the wheel in the air without transferring enough torque to other wheels to move the vehicle.
Theoretically you are right. But in practice, turning the free wheel takes more than just 0Nm. While the open diff can't multiple torque, torsen LSD can. Therefore, if you have suspended the front wheel, the rear wheels will get some torque. If spinning the wheels needs 1Nm, the rear will get 5Nm, assuming it is 5X multiplier. If that is not enough to move it, apply some resistance to the spinning wheel by braking or by providing external resistance.

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Different LSD? The question is whether the Indian Fortuner has an LSD at all - or is it an open diff? If LSD, logically (as you explained), it should be Torsen.
I haven't read beyond the previous page, I thought even the type of LSD was under question.
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Old 26th August 2013, 10:36   #216
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Default Re: Driving all four wheels: how is it done?

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Originally Posted by Samurai View Post
Theoretically you are right.
Time to try out the practicals - would you please do the honours with your GV and report back with a video ASAP? (The definitive "How to test if you have a Torsen LSD" guide)

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Old 26th August 2013, 11:02   #217
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Default Re: Driving all four wheels: how is it done?

Have experienced GV with center diff lock to move if one front or one rear wheel is spinning. If one front and one rear are spinning no movement possible. Without lock no movement.
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Old 26th August 2013, 11:16   #218
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Default Re: Driving all four wheels: how is it done?

I doubt that Toyota would launch a very different version of a fulltime 4WD vehicle - to crack open the market, and after such a long time. If they wanted to save costs they could have used the Hilux's part time 4WD system and not offered a fulltime 4WD version.

Quick Googling threw up these ASEAN links where Torsen is mentioned.

I had spoken to the Toyota ASC people, when I asked about LSD they got very shocked and said that they don't know anything about drugs :-)

Edit: forgot to paste the links. See below.

Btw it would be useful to have a discussion on how and where a Torsen LSD is useful. E.g. what it can do, apart from what it can't do. Would the Torsen LSD come with some preloading? Some versions do, I read. Else one can always brake and increase some resistance and see if that works.

Vietnam: http://www.toyotavn.com.vn/news/views/200/1888 (search for Torsen)
http://www.chaocom.com/vietnam-car-c...7-seats-2.html

Our friendly neighbours across the Western border: http://www.toyotafaisalabad.com/cate...t=tabs&base=28

Malaysia: http://www.autoworld.com.my/v2/news/...71&whichpage=2

http://paultan.org/2008/08/14/toyota...ails-revealed/

http://www.livelifedrive.com/malaysi...ner-suv-review

Last edited by nilanjanray : 26th August 2013 at 11:41.
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Old 26th August 2013, 11:27   #219
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Default Re: Driving all four wheels: how is it done?

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Have experienced GV with center diff lock to move if one front or one rear wheel is spinning. If one front and one rear are spinning no movement possible. Without lock no movement.
On level ground or some stuck situation? I am hoping on level ground, very little torque should be enough to move.
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Old 26th August 2013, 11:28   #220
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Default Re: Driving all four wheels: how is it done?

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Have experienced GV with center diff lock to move if one front or one rear wheel is spinning. If one front and one rear are spinning no movement possible. Without lock no movement.
How about with centre diff unlocked, using brakes intermittently to fool the Torsen into transferring torque some more? Does that produce movement?
Quote:
Originally Posted by nilanjanray View Post
...a very different version of a fulltime 4WD vehicle...
An open diff being cheaper than a Torsen diff...
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Originally Posted by nilanjanray View Post
Quick Googling threw up these ASEAN links where Torsen is mentioned.
What links?
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Originally Posted by nilanjanray View Post
...Toyota ASC people, when I asked about LSD they got very shocked and said that they don't know anything about drugs :-)

Last edited by SS-Traveller : 26th August 2013 at 11:30.
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Old 26th August 2013, 11:57   #221
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Default Re: Driving all four wheels: how is it done?

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How about with centre diff unlocked, using brakes intermittently to fool the Torsen into transferring torque some more? Does that produce movement?

What links?
Seems such braking manuevers were taught to US Army Hummer drivers (the Hummer used to come with two Torsen LSDs in the front and back).

But wouldn't it make sense to 'preload' Torsen (say, on demand) so that T x 0 = 0 never happens?

Why would the LC 200 - which has many state of the art technologies to choose from - continue to use Torsen?

Btw, edited my post above to include links.
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Old 26th August 2013, 12:17   #222
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Originally Posted by nilanjanray View Post
Edit: forgot to paste the links. See below.

Our friendly neighbours across the Western border: http://www.toyotafaisalabad.com/cate...t=tabs&base=28

Malaysia: http://www.autoworld.com.my/v2/news/...71&whichpage=2
Hmmm... interesting. Both the Pakistani and Malaysian Fortuners come with a different engine and different (4-speed AT) gearbox (albeit with Torsen centre diff) than the India-spec vehicles. Wherever in the ASEAN Toyota sells the 3.0 D4-D with MT, they are strangely silent on the existence of Torsen.

Apart from the question of whether the Indian Fortuner has a Torsen centre diff or not, it would be interesting to know if Toyota does have a non-Torsen centre diff for the Fortuner or not.
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Old 26th August 2013, 12:41   #223
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Default Re: Driving all four wheels: how is it done?

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Also does one have to replace an open differential to fit a lockable differential or is it something that can be modified and make the open differential adapted to, like taking eg. front differential of Safari 4x4.
I did some bit of reading on this last night and it keeps getting deeper, wow.

So found out that there are several options and characteristics but selectable seems the preferred one and of them, many speak highly of the ARB with few critical of it.
Some of the other options are:
ARB air lockers
Aubrun ECTED
Eaton ELocker
OX Locker
Yukon Zip Locker
Detroit Locker
Lock Rite
Maybe the main contributors to this thread can share some pros and cons of them.

However I still could not figure out whether the stock differential is replaced and whether the selectable is an add on.

Sharing an informational link, though I do not know whether what is written is correct:
http://www.pps.net.au/4wdencounter/a...difflocks.html

Thanks to Team BHP for kindling my interest in this, this thread is fantastic.

Last edited by s_pphilip : 26th August 2013 at 12:46.
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Old 27th August 2013, 10:20   #224
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Default Re: Driving all four wheels: how is it done?

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I wonder why so many are quick to start conjecturing about the lack of Torsen in the Fortuner.
After going through the sequence of posts this is your conclusion?
I wonder what it is about the Fortuner that makes most owners hypersensitive?

Anyway, right from the start we have been 'told' that the our Fortuner comes with a Torsen centre diff. Till now, it has never been questioned, so has been accepted on faith. And with passage of time without challenge, that faith grows. Now that it has been questioned, it needs to be resolved. The 'I say, you say' method is not going to resolve the issue. And so far, that is all we have. From both sides.

We should split our Fortuners into 3 batches: When first introduced, before facelift, and after facelift.
I can think of these mehods:
a) Checking relevant parts catalogue.
b) Checking relevant workshop manuals.
c) Physical examination.

Since nobody is going to strip the XFer case for this, physical examination means taking pictures of the outer casing of the various models and comparing these. We will need a 'Torsen certain' picture. With our wide membership, high chance someone will oblige. Assuming that different XFer cases have different casings.

Our 'operational tests' will not satisfy the diehard believers of whichever side comes worse off.

Writing a letter to Toyota might or might not work. Most probably not, because these queries are handled by the PR department, who are essentially clueless, and specialise in giving politically correct, cover their backsides answers. More so if it initially came with a LSD, which was later silently removed. (A possibility with the introduction of ESP. Pure speculation on my part though). However, given the minimal effort involved, worth a shot.

Quite possible that MM/ TML have stripped down their competitors vehicles. In which case they will also know. BD?

Where is the Guderian gang when you need them to chip in?

Regards
Sutripta

Last edited by Sutripta : 27th August 2013 at 10:22.
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Old 27th August 2013, 10:51   #225
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Default Re: Driving all four wheels: how is it done?

The fortuner, and many other full time 4WDs have a LSD center diff. I do know know what type it is though.
However, there is no LSD in the rear diff. Pajero has the rear LSD.

Fortuner everywhere in the world(4wd) has a LSD center diff. I doubt they will create something "special" for such a small thing.
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