Showing posts with label SAV. Show all posts
Showing posts with label SAV. Show all posts

Thursday, July 9, 2009

Comparison: Luxury SUV's Offroad



Sport Utility Vehicles. They are supposed to be all things to all people. Original examples evolved from 4WD vehicles that were capable of creating their own trail through rough terrain. Today, this segment has branched out into several different genres. The standard soccer mom SUV, the proper 4x4-geared SUV, the crossover and mini-SUV and finally, the luxury sport SUV.

 

This latter species is an odd one. Manufacturers who build these vehicles know that their wealthy owners will be much too scared of a little leftover winter sand on the road, let alone take them off-road. So the builders design these SUVs to handle like cars, and carve up tarmac corners instead of washed-out back roads. But they still build these luxury liners with AWD systems and even the most sports-oriented versions give the owner approach and departure angles in their spec sheets.

 

The whole train of thought behind an SUV is that these vehicles offer safety in adverse conditions. Many manufacturers also market these vehicles as passports to outdoor adventure, but will they actually survive in the wild? We got four different examples of these luxury SUVs and took them out into the great outdoors to see how they stand up against mother nature. Our trusty steeds in this experiment would be the Volvo XC90 R, BMW’s new diesel-powered X5, Infiniti’s FX50 and finally, the Land Rover LR3 HSE. All high-performance rides with the looks to match.

 

Infiniti FX50


Lets start with the highest performance version of these vehicles, the FX50. This is a truck that in reality is a high-performance sports car in SUV clothing. Its on-road abilities are truly amazing, and it could very likely make a couple of performance coupes look foolish on a track. However, the designs that make it a beast on the road should hinder the vehicle once the safety of tarmac is lost. The biggest weakness is the 21-inch wheels that are wrapped with 45-series all-season tires. When it comes to rough roads, this setup is a definite risk. Despite this, Infiniti lists the FX50’s approach and departure angles in the specs for the vehicle, and for a something so low to the ground (another hindrance in the back country) the angles are respectable.

 

The driving test proved the FX50 quite confident on gravel roads,  looking out for rocks and large potholes, and Nissan's great “RWD first” AWD system makes it a blast on clean winding gravel roads. It is clear that the suspension is tarmac oriented, so the FX50 does not feel like it is firmly planted on loose surfaces. If you decide to leave the beaten path, caution needs to be maintained, and only light off-road driving can be accomplished due to the vehicle's low ride height. Another problem we ran into was the strength of the centre differential. Under heavy load or when wheelspin began to be a factor, the centre viscous diff would overheat, leaving you with only RWD. Also, the absence of any underbody armour proves again that any off-roading in the FX50 should be kept to light terrain.

 

Volvo XC90 R


The XC90 is marketed much more to the adventurist than, say, the Infiniti or even the BMW. The name itself stands for Cross Country, so the ride height is higher, approach and departure angles are increased and there is even some skid plating mounted underneath, even if some is more for show. In terms of visibility and seating, the XC90 ranked top of our list. However, as Volvo prides itself on the on-road sportiness of the XC90, the 20-inch wheels mounted on our “R” version are risky, although our tester was set up with snow tires, giving us much more traction.

 

On the driving test, it had excellent driving characteristics on gravel roads, and the fear of damage from debris was not as high as the other vehicles, making for a more stress-free drive. It did tend to understeer when it got slippy. Off the beaten track, the XC90 proved remarkably confident despite its low height. The increased grip from tires and manoeuvrability of the XC itself had us heading into terrain we didn’t think was accessible. However, much like the FX50, the centre viscous diff proved to be a weak point as it, too, required cooling, leaving us with only FWD while in the field. All in all, we were quite impressed with the Swede, as it is capable of handling light-to-medium terrain, while being a sporty on-roader. Using the smaller 17-inch wheels available would make the XC an even more competent soft roader.

 

BMW X5 35d


BMW says that the X5 is just as good as handling a corner as the 3-series sedan. Having had an X5 on a racetrack, I can attest to this fact, as it is a force to be reckoned with. BMW has now released the turbo diesel version of the X5 in Canada, something I am ecstatic about as it now adds great fuel efficiency to the X5’s equation. But what about its off-road abilities? At 18 inches, the wheels are the smallest of the group and offer decent protection in a 55-series tire, which also turned out to be a snow tire on our tester. Like the Volvo, the X5 has some underbody protection, although its low plastic overhangs similar to the FX50 will have drivers keeping the approach and departure angles to a civilized level.

 

On our test drive, the Bimmer soaked up the gravel road with absolutely no problems, and remained neutral handling. It did have some of the stiff suspension float like the Infiniti produced. While the vehicle height had us on edge through the rough stuff, the Bimmer's low-range capability, and the strength of the diffs, meant that the drivetrain never experienced any problems no matter how sticky things got. While it was ideal to keep travel to mostly flat terrain, its capabilities were truly impressive, while the diesel always meant we had a good range of torque on demand.

 

Land Rover LR3 HSE


Now here is a special case. Land Rover has been the epitome of off-roading since the sixties, and the icon of any adventure expedition on any continent. With the Series Landies not in production, and very few Defenders making it to our shores, Land Rover has gone from farmyard worker to Military Recce vehicle, now ending up as a luxury vehicle driven by soccer moms and hockey players. So the question has to be, has Land Rover lost its off-road abilities that made the brand the most famous of any adventurer? NO!

 

While the LR3 looks more at home at the end of a red carpet, it still possesses the ability to get muddy. What makes it different from the others is its drivetrain. While the Volvo, BMW and Infiniti all use a standard clutch pack centre differential, the LR3 features a two-speed transfer case utilizing both high and low gearing, with locking centre, and optional locking rear, differentials. Land Rover has also added airbag suspension to raise the ride height for better ground clearance. Match this with a plethora of off-road-based electronics, and it is instantly apparent that Land Rover has not forgotten where it came from.

 

As you would expect, light and medium terrain come at ease with all these options. When it comes to hard terrain, the LR3 still remains competent, even if its limits are now being challenged. At this point, the same trouble of body overhangs and ground clearance begin to hang up the LR3. So, impressive off-road skill for such a luxury SUV to be sure. However, for these abilities, the Land Rover falls far behind the on-road abilities of the other three. 

 

Conclusion

After looking at four different luxury SUVs representing four different manufacturers built in four different countries, our conclusion may come as a bit of a surprise. The single biggest disadvantage to traveling off-road with these vehicles is the bodywork and tires. Taking these SUVs into the wild is like asking a painter to go to work in a tuxedo. You have to be willing to sacrifice scrapes down the doors and gouges in the bumpers, and if the size of the brakes permit, a smaller set of wheels and larger tires that will protect against punctures.

 

The truth of the matter is that for those who want to get out and explore the great outdoors, the terrain traveled is usually considered light if not just a gravel road. While the off-road capabilities of these vehicles are mostly medium-to-light, they are more than adequate for getting to 90 percent of the destinations that most outdoor enthusiasts desire. Obviously, if you are a dedicated wheeler, a more single-purpose, modified vehicle that won’t have you in tears when it rubs up against a tree, will be ideal. But for those who need to get back to work on Monday, and enjoy a luxury environment and sports car-like performance, then we found that a luxury SUV is well capable of doing it all.

 

 

The Specs

Infiniti FX50

Engine:  5.0L V8

Wheelbase/Track:  2,885/1,680 mm

Ground Clearance:  187 mm

Approach Angle:  28.8 degrees

Departure Angle: 20.9 degrees

Final Drive:  3.538

AWD System: Viscous Centre Differential-based full-time AWD

Curb Weight: 2,075 kg

Tires:  265/45R21

Electronic Aids: Only on-road safety aids

Price Base/As Tested:  $51,800 (FX35)/$59,900

 

 

 

Volvo XC90

Engine:  4.4L V8

Wheelbase/Track:  2,857/1,634 mm

Ground Clearance:  218 mm

Approach Angle:  28.0 degrees

Departure Angle: 25.0 degrees

Final Drive:  3.33

AWD System: Electronically-controlled multi-plate wet clutch-based full-time AWD

Curb Weight: 2,053 kg

Tires: 255/40R20

Electronic Aids: Only on-road safety

Price Base/As Tested: $48,595/$68,295

 

 

 

BMW X5 35d

Engine:  3.0L I6 Diesel

Wheelbase/Track:  2,933/1,650 mm

Ground Clearance:  210 mm

Approach Angle: 25.0 degrees

Departure Angle: 23.0 degrees

Final Drive:  4.44

AWD System: Electronically-controlled multi-plate wet clutch-based full-time AWD

Curb Weight: 2,370 kg

Tires:  255/55R18

Electronic Aids: Hill Descent Control

Price Base/As Tested:  $58,200/$62,200

 

 

 

Land Rover LR3 HSE

Engine:  4.4L V8

Wheelbase/Track:  2,885/1,613 mm

Ground Clearance:  240 mm

Approach Angle:  37.2 degrees

Departure Angle: 29.6 degrees

Final Drive:  3.73 – Transfer case Low/High: 2.93/1.00

AWD System: Two-speed electronic transfer gearbox, shift-on-the-fly capability with electronically-controlled variable-locking centre and rear differentials

Curb Weight: 2,629 kg

Tires: 255/55R19

Electronic Aids: Terrain Response System, Traction Control, Hill Descent Control, All-terrain dynamic stability control.

Price Base/As Tested:  $53,900/$64,200

Review: BMW X5 - Same X5 without the Spark Plugs


Late November 2007, I found myself lapping BMW’s performance driving Centre in the driving rain behind the wheel of the all-new BMW X5. With one of the head engineers guiding me around the track, he claimed to me that this new “SAV” or Sports Activity Vehicle as BMW insist on calling it, could handle a corner as well as its 3-Series sibling. After about ten laps I believed him, with the aid of the direct injected 4.8L V8 heaving the 2,380 kg SAV out of the corner with the utmost of ferocity. As a performance car enthusiast, I’ve never really been a big fan of this segment of vehicle, but the new X5 gave a good smack in the face that told me a versatile vehicle can also be fun to drive.

 

It was at this global launch that BMW teased us with the diesel version as the European media were also in attendance. While the gasoline powered X5’s impressed, the diesel powered version had me quite intrigued, although at the time, there were no plans to bring the diesel to North America. Truth of the mater is that North American’s (mostly American’s) just don’t like diesel vehicles, unless it’s a work truck. Well a lot has changed in the last couple years. Fuel prices along with environmental and economic concerns means that people are now looking to spend their money in a much smarter way. And thus the market is beginning to look at diesel in a whole new way.

 

And so we have it, the X5 diesel is here, now named the BMW X5 xDrive35d. Yup it’s a mouth full. This new line in the X5 breed features BMW’s award winning 3.0L Turbocharged straight six with the new BluePerformance Advance Diesel technology. So, what is BluePerformance, and what does it mean to you? Well this technology will likely make you think diesel rather than buying a smaller gasoline powered car.

 

BluePerformance is BMW’s result from the Bluetec development project. This was the research into making diesel technology cleaner and more socially acceptable. In other words, you get a diesel-powered vehicle with excellent mileage, huge power, with out the noise, smoke or smell of a conventional diesel powered vehicle. This done by utilizing direct injection from its common rail-type fuel system that contains fuel pressurized to 1,600 bar or 26,000 psi. Two turbochargers, mounted sequentially, keep turbo lag at a minimum while providing effortless power throughout the rev range, and giving the mid-size vehicle 265 horsepower and a massive 425 foot pounds of torque to complete the performance side of the equation.

 

On the environmental side, the diesels exhaust uses urea injection to lower NOX emissions. After being injected into the exhaust gasses, the urea solution creates ammonia that then converts the nitric oxides (NOX) in the exhaust into environmentally friendly nitrogen and water vapor. Like similar systems, the urea supply must be refilled occasionally, however, by equipping the X5d with 23 litres of urea capacity in a pair of tanks, one of which is heated to ensure a fluid urea solution in temperatures below -11 degree’s Celsius, BMW has managed to fit the urea refilling periods within the standard scheduled maintenance stops, and will cover the cost of the refills and solution for the first four years or 80,000 kilometers.

 

 So all this technical talk is all well and good, but does it make diesel a more seductive fuel alternative. In a word, yes! The result is that you have a vehicle with all the versatility of an SUV, the class and handling of a performance luxury sedan, the power of a large V8 matched with the economy of a small V6 sedan. I don’t know about you, but that sounds like a winning combination to me. And that’s exactly how it feels on the road.

 

The sheer amount of low-end torque means both nipping around town and passing on the highway are near effortless and more civilized acts. While a gasoline powered vehicle requires down-shifts to put the vehicle in the needed power band and the engine revs hard to pull you past slower traffic. With the diesel, you only have to press the throttle, and allow the momentum of torque thrust you forward. When matched to the xDrive AWD drivetrain, the usefulness of all this low down torque made the X5 surprisingly competent off the beaten path. The xDrive system includes a centre diff with a collection of clutch packs to provide torque to either front or rear axles, with a static distribution of 60% rear, 40% front, and the capacity to send full power to either end. With the DSC on, traction was maximized, and the lack of wheel spin got the BMW up a steep and slippery grade with ease. Conversely, with the DSC off, the diesel’s low-range torque and excellent six-speed automatic transmission kept the wheels spinning to power out of sticky situations. For a full report of how the X5 compared to its luxury SUV competition in off-road conditions, be sure to check out the Spring issue of Trucks Plus Magazine.

 

The only downside that I personally found with the diesel, was that it wasn’t gasoline. I love a great sounding engine, and the BMW straight-six does play a magical tune. Also, I love shifting gears and playing in the rev band, and you really just don’t need to with this vehicle. So, the diesel is almost too efficient for me, as high revving and gearshifts are simply not needed. For the average consumer looking at getting into an X5, this will likely not be a problem, and to be honest something I can easily live with.