XUV-500 AWD's High Altitude Performance Report Card-
Here is the much delayed report on XUV AWD's performance in the Himalayas. Due to the time constraint i could not post it earlier.
We covered close to 4000 kms for the whole trip in 13 days. We took Manali Leh highway for both ways, apart from the regular Ladakh routes, we also covered few more less visited places.
Just because i was driving a 4wd Crossover, i had the courage to take most of the shortcuts, and took the car to places which regulars refer as 4x4 terriotory. I had driven my Laura last year to Ladakh, so what was different this time? This time i was the only driver in the car, and only 2 of us- Me and my Wife were travelling to really remote places. Reliability had to be important, if the car failed there was no back up vehicle, or even back up driver. Unlike last time, i had nobody to help me with Navigation and spotting at tough places. I was the Driver, Navigator, Spotter, Photographer...
A few off road adventures before the trip helped to know my car's limits, advantages and downsides in challenging terrain. Most important aspect to master was having judgement of available ground clearance. Adapting to XUV's ground clearance was an easy task, the only weak spot is low lying engine guard, if you manage to steer the front wheels to avoid hitting the engine guard, rest of the car can cross without trouble on any kind of obstacles. For a Crossover, Ground Clearance is generous, but pit it against chassis based trucks and the front portion is placed quite lower, the rear portion is pretty high, and there are no low hanging parts are rear, ramp breakover angle is particularly very impressive for a car of this kind. Overall i did not hit the underbody at all, this was surprising for me since i was expecting some hits. Just once the engine guard touched the ground, few kilometers before Tso Kar i was taking a shortcut, the surface was loose sand, i was driving on tire tracks, a sudden dip appeared all of a sudden, possibly dug up by some stuck 2wd vehicle, i had an option to steer away, but it was split second decision, since the surface was soft sand i decided not to leave tire tracks, the front portion hit the sand but the hit was harmless.
Even the rear differential is placed high and even gets a guard to protect it. At places where tricky steering was required, additional grip from the AWD system helped me to crawl up slowly and take the obstacle confidently. I encountered many such obstacles in Zanskar valley, at one such instance the Xylo i was following took a bad underbody hit, the driver did not have any other option but to maintain momentum to pass through on a tricky climb on a dried stream crossing full of loose boulders, on the same obstacle i slowly and comfortably climbed with AWD lock in on position.
XUV AWD comes with a AWD system which relies on clutch pack(just like in DSG transmission) on rear differential to trasmit power to rear wheels when required. The AWD system is linked to ECU and ESP sensors, it relies on data from all these systems to split the power delivery. On Normal road surface the system acts a fwd system, the power is only sent to front wheels, only when the system anticipates the need for extra traction power is sent to rear wheels. The clutch pack based rear transfer case is really quick to divert the power within milliseconds, at times the AWD system anticipates the need for extra grip and splits power before even actual slip occurs, one such example is accelerating from a traffic signal the rear differential is power even before the front tires start to skid.
Along with the quick transfer of power to the rear axle, the most impressive aspect for me is the seamless way in which power shift occurs, the occupants in the car or even the driver does not even get to know when the rear differential is powered. Compare it to the actuation of mechanical AWD system in Rexton MT in normal Torque on demand mode, the system in Rexton is Slow and Jerky, in quite a lot of instances i make out the activation of AWD system. This AWD system in XUV is more than capable to handle occasional Slush, Muck and Snow and a lot more.. But the real disadvantage is lack of low range gearing, i am not complaining here, i clearly know low range in a crossover of this kind is asking too much, many other crossovers do not even have any of 4wd system, not even as an option. Both front and rear differential are open kind, Traction Control system from ESP is the only facility to balance excessive wheelspin on the same axle.
The AWD system is pretty smart, no human intervention is required majority of the times, the only control in the cabin is the AWD Lock switch, which permanently locks the power split making it behave like a locked center differential till a particular speed or until the system detects possible transmission windup probability. This switch exists to help in scenarios where you know slip will occur, like starting on a icy incline etc. Rest of the times leave the task of splitting power. I even recorded a Video to show the quick response time of the AWD system.
In this trip, i got the first oppurtunity to use AWD system properly at Baralacha La, we reached this pass quite early in the morning, the temperature was sub-zero for sure, the water on road was frozen to form ice and there was fresh snowfall. While all other Vehicles were climbing with some drama, especially the rear wheel driven Xylos and Innovas which were dancing a bit as the rear tyres were losing traction, my XUV climbed slowly and comfortably without any need to carry extra momentum. Similar conditions with heavy snowfall and some slippery surface greeted us at Khardung la, where we spent close to 5 hours stuck in a Jam because other 2wd vehicles were finding it hard to climb, the XUV AWD even with H/T tires conquered this high pass comfortably where all others were struggling with traction.
At many places i did miss the Low range gearing, in this trip i attempted quite many steep shortcuts, just because my car did not have low gearing i had to use some momentum to keep the engine in its sweet spot to deliver enough torque to see us through, this meant a bumpy ride at places. And if i had to slow down to tackle a turn to or some high obstacle i had to start with some slip of clutch. XUV AWD uses the same gearing ratios as the Fwd version, the ratios have been tuned for best possible FE. Out on Highways, the choice of widely spaces tall ratios seems like a good decision but off the road the long first and second gear feel a bit too tall, i feel a shorter first gear should have been provided to compensate for lack of low range.
A high altitude, as expected the low end portion of the rev range before the Turbo kicks in, the range from idle speeds to 1400-1500rpm is most severely affected due to lack of oxyzen. The otherwise punchy low end of XUV suddenly disappears, the power delivery becomes peaky. It is only after 1600rpm a sudden torque wave arrives, the engine stays punchy beyond this point. This power loss in not unique to this Vehicle only, it strikes on all the engines.
On my previous trip, the TDI(CR) engine in my Laura adapted much better to Altitude, all because of a single built-in function, where the engine automatically raises the idle speed to 1200rpm at such high Altitude, to compensate for loss of grunt at lower rpm, but just because this does not happen in m-hawk engine of XUV, starting off on inclines is a tricky affair. A generous dose of Accelerator Pedal input has to be applied and revs have to be piled till 1200-1300 rpm before starting off to prevent engine from bogging down, i always tried to avoid slipping the clutch and always preferred to let it go quickly to save clutch wear.
At Altitude due to lack of Air, the Turbo-Charger starts making an annoying and crude whistling Noise which is completely absent at lower Altitude. The Engine stays quite refined otherwise, the clatter typically made by older Common-Rail engines like Innova is almost absent here. Scorpio and Xylo take a long crank to start at high Altitude, if i remember it right, it was due to missing Glow Plugs. My XUV did always start with short crank, i do not know if there any changes to the Engine or Glow plugs have been added.
Ride quality on non existent roads was not as supple as traditional SUVs, i'd blame it on the Monocoque construction and lower travel independent stiff suspension all round tuned for more towards better Dyanamics and high speed behaviour than handling off road obstacles. The underlying stiffness was always present at low speeds, but at bad roads which allowed us keep the speed high Ride quality was much better, but all in all the ability to stay flat most of the time made the trip very comfortable. Just like all other stiffly sprung vehicles, XUV's ride improves with speed. I really have no complaints in regard to Handling and Overall dynamics, not only is the Handling safe enough to carry much more speed than Chassis based SUVs, after you get used to the behaviour of this vehicle, it starts to feel reasonably involving too. The steering maybe Vague at times and Over-servo'ed for a Hydraulic setup, i liked it for being pretty quick to respond and comparatively direct for enthusiastic driving. This AWD variant does not suffer from annoying Torque steer which is a problem in 2wd variants.
Amongst the Electronics which come bundled in this top end variant of XUV-500 AWD, i was most impressed by HDC- Hill Descent Control. Along with the extra traction from AWD system, this brilliant system helped me go down super steep shortcuts without using brakes. This system works like a charm, it automatically brakes individual wheels to keep the speed in check but still never lets any of tires to lock up. After initial trials on relatively easy places, i felt confident enough to take on each and every downhill shortcut, which otherwise i would never have attempted without low range. This system impressed me so much that i even go on to claim that this system is as helpful as low range going downhill, even after repeated usage i did not experience brakes overheating or brake fade.
HHC-Hill Hold Control was great help too, it saved me a lot of effort at high altitude traffic jams. TPMS- Tire pressure monitoring system helped me save 14k bucks, on a rough road a sharp pebble got lodged in the tire tread, just because TPMS threw an Air loss warning i could fix the puncture in time or else in a minute or two the tired would have permanently damaged beyond repairable state, without me knowing. At high altitude passes, at close to freezing temperature this TPMS system sounded a few false alarms.
There was a big irritant though, the front suspension rattled all the time, just because front stabiliser bar bushes were worn out. I visited 2 different service stations to get it sorted, first one clearly denied of hearing any noise and the other one failed to fix it, even after i got the Regional office involved. After coming back, i visited the service station again, took the RM and Works Manager on a test ride, pointed out the rattle and insisted on getting each and every suspension component opened up to trace the source, it worked. This was a simple half an hour Job, the defective anti roll/stabiliser bar bushes were the culprit. I use the word defective because this is a known defect, still it has not been included in recalls, my own car is running on 4th set already in just 20k kms. SHAME on you Mahindra.
Overall my XUV-500 AWD did great on the trip. There were no issues to report, performed flawlessly all through out. Made its own road at places, ventured into 4x4 territory and came back impressed. Overall performance was above my expectations. With good driving skills, this vehicle can take you just about anywhere.
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