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Old 2nd November 2015, 00:26   #16
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Default Re: Mahindra XUV500 - FWD or AWD?

@ general_neo

Nomenclature is easily confusing.

Full-time AWD or Full-time 4WD (i.e. Rexton): All four wheels get torque transferred to them all the time regardless of the terrain.

AWD with Interactive Torque Management (ITM) or Part time AWD (i.e. XUV AWD): In case of FWD vehicles with AWD, when the front tire or tires have a slippage/loose traction, the ITM sends the torque to the rear wheels to keep the vehicle on track. Thus rear wheels only get torque when needed. These type of systems also have an AWD lock mode, in which torque is transferred to all 4 wheels till the lock is disengaged. This AWD lock mode can be activated with a single switch "AWD Lock". Some manufacturers disengage the AWD lock after a certain speed and some don't.


Last edited by GTO : 2nd November 2015 at 09:42. Reason: Quoted post deleted
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Old 2nd November 2015, 00:29   #17
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Default Re: Mahindra XUV500 - FWD or AWD?

XUV AWD is full time AWD, Normally it will give out 60% Power in the front and 40% Rear, Pressing the AWD lock button will split the power 50% in both front and rear tyres.

Once i had just pressed the AWD lock button after starting and the engine just to check if everything is working fine, I forgot to disable it before starting to drive and it was on all the time and i had crossed 100 Kph, Later on when i saw the button it was still lit up.
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Old 2nd November 2015, 08:18   #18
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by Tanveer_2558 View Post
i had crossed 100 Kph, Later on when i saw the button it was still lit up.
The LED icon of the AWD might be lit-up but I doubt, it would be functioning [as intended] on that moment.
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Old 2nd November 2015, 09:34   #19
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Quote:
Originally Posted by falconion View Post
I am not sure of the speed at which the XUVs AWD lock gets disengaged. I have taken it upto the speed of 60-70 without the AWD lock getting disabled. I did not want to take it up higher than that.
The LED staying on does not indicate the status on power split or whether the system is engaged, it only says you have asked for the lock. The light would stay even at 200kph.

Quote:
Originally Posted by general_neo View Post
Seriously? They aren't full time AWD? i was assuming that they are full time when they say AWD
... Otherwise they are 4WD....
No these are Part time, Torque on demand systems, not full time AWD.

Quote:
Originally Posted by Tanveer_2558 View Post
XUV AWD is full time AWD, Normally it will give out 60% Power in the front and 40% Rear, Pressing the AWD lock button will split the power 50% in both front and rear tyres.

Once i had just pressed the AWD lock button after starting and the engine just to check if everything is working fine, I forgot to disable it before starting to drive and it was on all the time and i had crossed 100 Kph, Later on when i saw the button it was still lit up.
No it is not full time AWD, it is part time Torque on demand AWD, not full time with center differential.

The same Borg Warner ITM was used for last gen Hyundai Santa Fe, and AFAIK for Tucson and Kia crossovers. I had done my research before buying the car.

Here is the description on how this system works:
Quote:
Hyundai's new system uses a computer-controlled clutch mechanism mounted in front of the rear axle to engage the drive. It is a Borg Warner system that can provide up to 99% of the torque to the front wheels, but automatically diverts up to 50% of the torque to the rear wheels when needed. The driver can push a button on the dash as an input to the computer, commanding it to "lock" the torque transfer at 50/50 for getting out of slippery parking spots in winter or ploughing through some soft sand. While there is no low range in the Santa Fe all-wheel drive system, it is more than capable of handling many off-road excursions.

Because the torque transfer to the rear wheels is variable, a dependable, durable clutch mechanism is needed that can be instantly engaged. To do this, the computer monitors wheel speed, accelerator pedal movement and steering inputs. When 4% or more front wheel slip is detected, the rear axle starts to engage. It can also anticipate the need for additional traction and engage the AWD system when the driver accelerates the vehicle. Another feature is it can disengage the rear axle during ABS events to optimize ABS stopping.

The computer controls a large solenoid coil in the clutch housing. When energized, the solenoid pushes against a multi-plate clutch, which in turn holds a washer-like plate from turning. Ramps and balls between this plate and a second plate cause the two plates to be forced apart, placing pressure on a second larger multi-plate clutch that connects the driveshaft to the rear axle. The path of torque is complete and the rear wheels drive.

A button on the dash can lock the clutch to provide 50% torque to the rear wheels, but this only occurs below 35 kph. Above that speed, the computer pulses the solenoid to disengage the clutch mechanism, but it will automatically engage it again when vehicle speed lowers.

Finally, the system monitors steering wheel angle. Turn the steering wheel, such as when parallel parking or turning a tight corner and the computer will decrease the torque applied to the rear wheels to there is no driveline binding during the turn.

Computer controls, electric solenoids and data communication between computers are all used to provide smooth traction regardless of the driving conditions and optimize fuel economy too. That's modern all-wheel drive.
Source:Link.

Quote:
Originally Posted by falconion View Post
Nomenclature is easily confusing.

Full-time AWD or Full-time 4WD (i.e. Rexton): All four wheels get torque transferred to them all the time regardless of the terrain.
I hope you know Rexton comes with 2 different AWD systems:

The top of the line RX7 Automatic gets a full time AWD system, the center differential cannot be locked for 50:50 split, has no low range. Intended for road usage, not good off road.

RX5 manual, gets a Torque on demand type, part time AWD system based on Rear wheel drive system, but this also gets Low range gearing reduction with 50:50 lock. Not intended for road usage, but works great off the road. The torque on demand system is old type operated through viscous couplings and not through the clutch pack(like the one in XUV), as a result it is not as seamless and i have observed a few jerky false actuation's(like when accelerating while taking a tight U turn).

The rally Mahindra Super XUV, has a work around for this AWD system which gets disengaged at speed. They got a cheat device designed from Racedynamics, which sends false data to AWD system to keep it engaged. The downside is the AWD clutch pack lasts only for a short period.



And it's not only this AWD system which gets disengaged at speed, most others at this price point also do, example Renualt Duster and Skoda Yeti. All these compact AWD systems send little to Zero power to the rear axle at speed usable for cornering.

Last edited by .anshuman : 2nd November 2015 at 09:50.
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Old 2nd November 2015, 09:51   #20
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Default Re: Mahindra XUV500 - FWD or AWD?

Straight from the horse's mouth. IMHO, buying an SUV without AWD / 4x4 is like buying a Porsche with a top speed of 100 kph.



Here's a video by Anshuman (there are more on YouTube).

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Old 2nd November 2015, 11:48   #21
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Default Re: Mahindra XUV500 - FWD or AWD?

This video explains it very well. Is there a problem like overheating or any other when Xuv like AWD system is run for long duration and what is that long duration? If it is so does it differ when you put the system in lock mode? I understand that the system is always in auto and disengages automatically when not required, but when used in Lock mode for long duration is it an issue, and is a full-time 4wd preferred if the driving is going to be that way?
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Old 2nd November 2015, 12:11   #22
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by J.Ravi View Post
Here are my views on XUV 500 FWD v AWD:

I faced two anxious moments during my recent Uttarakhand trip.

1. ...... When my turn came, I drove in the first gear, but my XUV 500 could not pass in the first attempt. So, I came down, again revved the engine, gathered the required momentum, drove faster, without depressing the clutch pedal, not bothering the boulders and XUV 500 passed in the second attempt with some fellow-drivers pushing from behind!.....

2. .......... I started crawling the steep stretch in the first gear, but XUV 500 got tired mid-way. So, I backed down, gathered enough momentum, drove faster in the first gear and XUV 500 passed in the second attempt without any external help.
The two incidents when the XUV couldn't climb, did the front wheel spin ?

Regards,

Pawan
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Old 2nd November 2015, 12:57   #23
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by naikameya View Post
This video explains it very well. Is there a problem like overheating or any other when Xuv like AWD system is run for long duration and what is that long duration? If it is so does it differ when you put the system in lock mode? I understand that the system is always in auto and disengages automatically when not required, but when used in Lock mode for long duration is it an issue, and is a full-time 4wd preferred if the driving is going to be that way?
Yes some reports i have read say the system can overheat when abused, especially in Sand. It starts working fine again when it cools down, It's cut off by electronics when it heats up.

But the AWD system in my car has never overheated, I have repeatedly driven on loose Sand and Mud a lot of times just for fun.
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Old 2nd November 2015, 13:23   #24
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by PapaBravo View Post
The two incidents when the XUV couldn't climb, did the front wheel spin ?
In the first incident at Badrinath, yes, the front wheel was spinning. In the second incident at Mussoorie, my XUV 500 struggled a lot to pull even in the first gear on the steep slope as I was crawling without any front wheel spinning.
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Old 2nd November 2015, 13:38   #25
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Default Re: Mahindra XUV500 - FWD or AWD?

The AWD will have lesser fuel efficiency than the FWD, also you will have to factor in wear and tear to the AWD components

It finally boils down to finances. If you are willing to invest that little bit extra on the AWD, you would be repaid with peace-of-mind that your vehicle is capable of going to places where the FWD would struggle to. Also, you would require the additional capabilities of the AWD only 2-3 percent of the time

The AWD is not a low ratio gear box, so even though the ground clearance may permit it, you would not be able to undertake hard core off-roading with the AWD

If you are looking at a highway cruiser and a poser in the city, then the FWD would be enough
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Old 2nd November 2015, 13:59   #26
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Default Re: Mahindra XUV500 - FWD or AWD?

In Autocar India's comparison, the XUV's AWD system did heat up and it needed multiple attempts to get up a hill that the others managed in one.
http://www.autocarindia.com/auto-fea...ty-397740.aspx
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Old 2nd November 2015, 14:37   #27
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Default Re: Mahindra XUV500 - FWD or AWD?

To be honest there is not much of a fuel efficiency difference. I have noticed at most 1-2 kmpl difference. And on the highway it performs similar to the FWD variant in terms of efficiency.

XUV uses NexTrac by BorgWarner for Torque Transfer to the rear wheels which for the most part is maintenance free, requiring oil change every 50,000 km (1.2 l). And the PTU (power transfer unit) also requires oil change every 50,000 km (0.8 l).

As for wear and tear of AWD components, you have to realize the XUV is not a full off-roader. And the typical consumer base is going to drive it in the city or highway with slight off-road. In city or highway the AWD system is mostly inactive until circumstances dictate it to activate, i.e. during slippage or loss of traction, hill climb, sand, mud, slush, etc. Thus when the system is not frequently used there will be very minimal wear and tear.

AWD provides peace of mind when driving in our countries pot hole erupting earth swallowing distorting speed humps of pathways we call roads.
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Old 2nd November 2015, 14:42   #28
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by nd4$pd View Post
In Autocar India's comparison, the XUV's AWD system did heat up and it needed multiple attempts to get up a hill that the others managed in one.
http://www.autocarindia.com/auto-fea...ty-397740.aspx
It normally does not heat up easily unless abused hard, with careful driving, even on Sand dunes or continuous operation in mud I have never come across any heating issues. Also in the other comparison test in the same magazine, the car tested is w10 AWD but figures specs and other information provided is for w8 2wd.


Last edited by .anshuman : 2nd November 2015 at 14:47.
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Old 2nd November 2015, 18:33   #29
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Default Re: Mahindra XUV500 - FWD or AWD?

Just out of curiosity - did you consider the Duster AWD? If you did consider it and rejected it, might help to know why?
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Old 2nd November 2015, 21:06   #30
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Default Re: Mahindra XUV500 - FWD or AWD?

Quote:
Originally Posted by Tanveer_2558 View Post
XUV AWD is full time AWD
Nope. The XUV AWD will also drive in FWD mode for most of the time.

Only when the system feels that the rear wheels need to be powered due to loss of traction/ hard acceleration, the centre diff is locked and there's a 50:50 split of Torque.

Some cars have a lock with 60:40 split in torque.
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