[Turbanator]

Originally Posted by Touringlawyer

But when you say something like "that is BS", it doesn't help. We, commoners, expect some reasoning based explanation from experts like yourself. So I would be grateful if you could contradict and explain how the Torque Multiplication bit is wrong.

Again, when someone says that Pajero Sport in 4x4 LLC mode would be producing more than 900 NM of torque, I am sorry, I cannot think of anything better. Perhaps feeling sorry for the guys who work with such training and take unsuspecting customers for a ride.

Looks, you have still not understood what I am trying to tell. Any engine will have a peak Power & Torque, that will be available at some RPMs/ Gear combination. These figures are the maximum any engine/ vehicle can produce irrespective of the Gear or low range combination. Torque will be dependent on the selection of the gear, usually smaller gears will have more torque but the specifications should always mention Maximum Torque. If that's not the case then what's the point of having Specifications listed at first place? Please note that my views are not as an expert but as a common man.

Dear Experts,
After an explanation by a fellow BHpian who stated that the Torque figure does not change and remains the same in all gears though available at a lower range of RPM

Cross posting from your post at the other thread, this does not appear correct. Torque should change just like Bhp depending on the RPM and selected gear.

[Touringlawyer]

Originally Posted by roby_dk

Do let us know in case you find answer to your queries.

Edit:https://www.team-bhp.com/forum/4x4-t...ml#post3324760 (Torque generation and distribution)

roby_dk, thanks a lot for referring me to the right thread. Really appreciate.

Folks, I had put my query on the relevant thread as pointed by roby_dk and Samurai (Team BHP Moderator) has very beautifully explained Torque and clarified about Torque Multiplication in that thread.

You can go to that thread and read his explanation there. I have put a further query to him. I think his responses would clarify the doubts even better.

[Czarcarsm]

Just my two cents at clarifying this torque question.

In gears the fundamental formula is, when 2 gears are engaged, the torque transferred is proportional to the diameters (also called gear ratios). So smaller gear with 100 Nm of torque when engaged with a 2nd gear of twice the diameter, will generate twice as much torque. That is 200 Nm from gear 2. This is the fundamental principle governing gears and this is used in automotive gearboxes.

So if a vehicle, considering gearbox, differential etc, has a gear ratio of 2, then the torque at wheels will be twice the engine torque. But there is an important catch !

The catch is called differential, which splits the torque. In a 2WD vehicle the torque available at the differential is split in half and send to both the driven wheels equally - 50/50, when the vehicle is moving down a straight line. Similarly in a 4WD, the torque is split 4 ways. But, oh well there are few more catches !

Some 4WD vehicles split torque 60% ( sent to front axle ) & 40% ( sent to rear axle).

And finally the torque is also split or not split based on electronic traction control, differential lock, whether the vehicle is turning etc.

So the important thing is the torque at wheels is always split based on 2WD or 4WD. This 800 Nm for Endy is actually split 60/40 for each axle. Then further split in half, for each wheel.

I have a vague feeling that 300-400 Nm may be the max torque each wheel can handle before it looses grip with the ground. Rubber on pavement has a max friction 'capability'. If wheel torque overcomes this friction, then the wheels will loose traction and will slip. Then traction control takes over, moving torque to other wheels that has grip.

Hope this helps.

[Czarcarsm]

An update to my above post or torque.
The 300-400 Nm limit I mentioned as max possible torque before loosing grip, is specifically for Endy. What matters is the force at the interface of tire and pavement. Torque depends on tire diameter as well.

[roby_dk]

As per the calculation by Samurai in below post I tried to calculate the max torque generated by Endeavour.

https://www.team-bhp.com/forum/4x4-t...ml#post4496502 (Torque generation and distribution)


Note: This is an ideal scenario which is impossible to achieve in real time.

[anshuman77]

Hi

Does anyone have experience in getting their car serviced at PPS ford service station in Domlur Bangalore?

I am coming up on my 2nd year service and wanted to check this out as an option

[mayanksabharwal]

This is the third reported incident of new Ford Endeavour catching fire, second in India. Unfortunately, this is the first incident in which death has been reported. May his soul rest in peace.

Source - Rushlane

https://www.youtube.com/watch?v=OUMcaGBBg8E

[vishy76]

Originally Posted by mayanksabharwal

This is the third reported incident of new Ford Endeavour catching fire, second in India. Unfortunately, this is the first incident in which death has been reported. May his soul rest in peace.

Source - Rushlane

This car belongs to a friend of mine. His father lost his life

This is the second such incident in India and third worldwide. If foul play is ruled out, I am going to do all I can and take Ford to task.

Their ignorance has cost my friends family a life! I am also going to ask them to do a thorough investigation as well and publish the findings here. Ford HAS to have an answer now.

[BlackPearl]

Originally Posted by vishy76

This car belongs to a friend of mine. His father lost his life

Extremely sad to hear this. May his family have the strength to cope up with the loss.

I always thought it takes a lot of effort for a diesel vehicle to catch fire. It seems I was wrong.

[Surprise]

AG has pointed out in one of the WA group, the engine bay doesn't look like caught fire first & it was from back of the car. His observation seemed to be right as there is no/very minimal smoke from the bay. Hope the detailed analysis from Ford bring out more facts

[rutvij]

Very shocking. This has been covered in both English and Gujarati news papers. However both has different versions to tell. According to TOI, no one was aware that there was anyone in the car. Whereas Divya Bhaskar says that he blew horn for 5 minutes but died before help could reach him.

My thoughts are with family who lost their kin to this avoidable tragedy.

Ford must make an honest and thorough investigation into this incident and if required take corrective measures immediately.

p.s. not able to upload newspaper clips. Will do so later from computer.

[AirbusCapt]

Originally Posted by Turbanator

Again, when someone says that Pajero Sport in 4x4 LLC mode would be producing more than 900 NM of torque, I am sorry, I cannot think of anything better.

Looks, you have still not understood what I am trying to tell. Any engine will have a peak Power & Torque, that will be available at some RPMs/ Gear combination. These figures are the maximum any engine/ vehicle can produce irrespective of the Gear or low range combination. Torque will be dependent on the selection of the gear, usually smaller gears will have more torque but the specifications should always mention Maximum Torque. If that's not the case then what's the point of having Specifications listed at first place? Please note that my views are not as an expert but as a common man.

The experts seem to disagree.
https://www.cartoq.com/mahindra-scor...el-drive-suvs/
Extract of the relevant bit below:

SUV becomes torque monster in low ratio

The low ratio gearbox is meant to be used in extreme situations for a reason. In the 4-low mode, the torque output of a SUV increases by at least 2 times. This increase in torque enables the vehicle to tackle sticky situations and get out of them without much problem. However, it should be put into use only when it’s really necessary to do so. For instance, in normal mode, the Mahindra Thar offers a torque output of 247 Nm. However, with the 4-low engaged, the torque output increases to a whopping 600 Nm. Now you see the difference.

[rovingeye]

Originally Posted by rutvij

Whereas Divya Bhaskar says that he blew horn for 5 minutes but died before help could reach him.

This is shocking and scary. My condolences to the family that lost a father.

Just very curious though - why wasn't it possible for the occupant to roll down the window and jump out (assuming the door may have jammed)? Is it because the fire just burnt out the electrical circuitry and the windows were therefore impossible to roll down? Also, why would the door jam at all, in the first place even if there is an accidental fire?

Edit : Sorry, just read that his seat belt had unfortunately jammed. What an irony that a piece of equipment meant to keep you safe took a person's life. Sad.

[debuda]

Originally Posted by Touringlawyer

While test-driving the Pajero Sport manual some months back, the sales person had told me that the Pajero Sport in 4x4 LLC mode would be producing more than 900 NM of torque, which should be able to cross any hurdle / very difficult hurdles.

Originally Posted by Turbanator

Sound BS to me, the Torque and Power graph for any Car or engine for that matter will be a curve and the values that we see on the specifications will be the maximum in a particular gear/ RPM, latter being mentioned in the spec sheet. Just by changing to Lower gear or putting into 4x4 Low, these cannot increase beyond the maximum.

Touringlawyer came up with a legitimate doubt but was unfortunately ridiculed by some people due to their ignorance of basic physics. Though some others have subsequently shed light on the issue, permit me to clarify the matter by adding my 2 cents.

1) Engine torque Vs Wheel torque : This is the most fundamental concept which is widely misunderstood. The value of maximum Torque (e.g., 385 Nm for my Endy 2.2L) quoted by any automobile manufacturer is the maximum torque the engine is capable of producing at the crankshaft. On the other hand, the torque which finally reaches a particular wheel after passing through the transmission is called Wheel torque. The combined Wheel torque of all the driven wheels can be significantly different from the Engine torque.

2) Torque can be multiplied or amplified : Most common way of increasing torque is by reducing RPM through gears. Between the engine and the wheels, RPM reduction (with associated torque amplification) happens at the gearbox, transfer case (in 4x4 cars) and differential. In automatic transmissions, fluid couplings can also amplify torque and that is why these couplings are called Torque Convertors. If my Endy 2.2 engine is operating at 1600 RPM and developing 385 Nm torque under certain conditions and the transmission is in first gear, the total torque at the rear wheels could theoretically be around 5,000 Nm, i.e., approx 2,500 Nm torque per rear wheel (Endy 2.2 is Rear Wheel Drive).

Let us look at the following two diagrams of a RWD powertrain :

As depicted in the image above, the engine is the source of torque. The gearbox is connected to the engine through the clutch (on a manual transmission) or torque converter (on an automatic transmission). We consider that there is absolutely no slip in the clutch (fully closed) or in the torque converter (lock-up clutch closed). In this case the engine torque Te is equal to the clutch / torque converter torque.

Further, the engine torque is transmitted through the gearbox, where it is multiplied with the gear ratio of the engaged gear Ix and outputs the gearbox torque. Tg=Ix*Te

The propeller shaft is transmitting the torque to the rear axle, where it is multiplied with the final drive gear ratio Io. This gives the torque at the differential Td. Td=Io*Tg=Io*Ix*Te. I am not sure about the actual gear ratios and differential ratio in my Endy 2.2 and for the sake of illustration let me assume a gear ratio of 4 (in 1st gear) and a differential ratio of 3. With these assumptions, Td=4*3*385=4,620 Nm.

If the vehicle is driven on a straight line, the torque at the differential is equally split between the left wheel Tlw and the right wheel Trw.
Tlw=Trw=Td/2=2,310 Nm.

It is thus quite clear that engine torque can be multiplied manifold by the transmission before it reaches the wheels. In 4x4 cars there is a transfer case which may have additional gear ratios in high range and low range. This ratio will further amplify the torque.

3) Wheel Force and Traction : Let us try to understand how the Wheel Torque actually propels the car forward (or backward). We know that torque is the product between a force and its lever arm length. In our case, the wheel torque is applied in the wheel hub (center) and the lever arm is the wheel radius. The radius of Endy wheel (265/60 R18) is about 0.4 m. Continuing with the above example, Tlw=Trw=2,310 Nm=Fwl (Wheel Force)*0.4. From this equation, Wheel Force on each of the rear wheels on my RWD Endy 2.2 works out to 5,775 Newtons. So the total force available to propel the car is 5775*2=11,550 Newtons.

Let us now closely observe what is happening at each of the rear wheels. While the tyre is applying a tangential force of 5,775 Newtons on the road, the road is applying an equal and opposite force of 5,775 Newtons on the tyre. This is where the concept of Traction comes in. Traction is basically the gripping power between the tyre and the road. It depends on several factors but the most important ones are tyre footprint (area of tyre in contact with road), co-efficient of friction, and vertical load on tyre.

4) Greater traction in 4x4 : Let me end my post by highlighting the concept of traction while comparing 4WD with 2WD. Let us assume that total Wheel Torque available in 4WD and 2WD are identical and the torque is distributed equally. In that case, the total Wheel Force (11,500 N) would also be identical, the only difference would be that in 4WD the Wheel Force on each of the 4 wheels would be 2,887.5 N and in 2WD the Wheel Force on each of the rear wheels would be 5,775 N.

Now let us put a number on Traction, which too is a Force that can be expressed in Newtons. If the Traction on each wheel is greater than 5,775 N, both the 2WD and 4WD would move with equal ease and acceleration. But in a case where the traction is greatly reduced, say to 3,000 N per wheel due to ice on the road, the rear wheels of the 2WD would start spinning and car won't move. But the 4WD would move easily because the total traction (12,000 N) is still more than the total Wheel Force (11,500 N).

Disclaimer : Figures of gear ratios, torque, wheel force and traction are merely illustrative.

[Turbanator]

Originally Posted by debuda

Touringlawyer came up with a legitimate doubt but was unfortunately ridiculed by some people due to their ignorance of basic physics.

Since you have quoted me, I reiterate that I still find these figures wrong -

the sales person had told me that the Pajero Sport in 4x4 LLC mode would be producing more than 900 NM of torque

What you or others have answered is Torque at wheels wrt different gears, my answer was regarding someone quoting figures about twice as mentioned over the specifications. If I am wrong in my understanding, can you or anyone else help me to understand how can this figure of 900 NM in 4x4 LLC mode in Pajero be correct? And if it's correct then why has manufacturer mentioned much lower figures on their spec sheet?

Or for that matter, if the torque figures at wheels are so important for any SUV/ Car, why do manufacturers do not mention on their spec sheet? And should we choose a 4x4 after doing all calculations of Torque available at wheels considering Engine Torque, Gear ratios and wheel Dia?

I have also never seen any reviews or comparisons anywhere including here, which says that an X SUV has 100 Nm in 4x4 at wheels and Y has 120 Nm so the Y will able to handle a demanding situation better then X if everything else is same!