Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Kia Sportage LX-V6 Luxury. Click image to enlarge

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2009 Acura RDX

By Paul Williams

Ottawa, Ontario – At www.Autos.ca we are regularly asked if all-wheel drive (AWD) is “worth it.” “Do we really need it?” is the typical question. “Isn’t it just an added expense?”

Well, it is an added expense, that’s for sure, both when you purchase the vehicle and in its operating costs (fuel consumption is typically greater in an AWD vehicle). But if you have occasion to drive in snowy, icy conditions — which applies to just about all Canadians — you’ll find a definite improvement in vehicle control with all-wheel drive. There’s no doubt about it.

Acura’s SH-AWD (Super Handling All-Wheel Drive), as found on the RDX, is a permanent all-wheel drive system that requires no input from the driver. There’s no centre-locking differential, and no low or high ranges that you’d find in some four-wheel drive vehicles. Although these features are fairly typical of AWD systems from a number of manufacturers, the SH-AWD system has additional technology to recommend it.

For instance, like many permanent all-wheel drive systems, SH-AWD distributes torque between the front and rear wheels via a torque transfer unit. Specific to SH-AWD, torque is also shifted between the left and right rear wheels (called torque vectoring) by a pair of electromechanical clutches.

Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Acura RDX. Click image to enlarge

Additionally, SH-AWD can “overdrive” the outside rear wheel in a turn. What this means in practice, according to Acura, is that by rotating the outside rear wheel faster than the speed of the front axle, the system can “yaw the vehicle through the turn while cornering.” The idea is to relieve the front tires of some of the work of turning the vehicle, thus reducing understeer and improving handling balance and control (Acura has a useful graphical representation of this process on their Honda technology site).

The SH-AWD system is also “proactive,” in that sensors detect and compensate for wheel slippage by distributing power between the front and rear axles and the rear wheels continuously. Power distribution is as follows: up to 90 per cent of available driveline torque can be transferred to the front wheels during high-speed driving; during straight line full-throttle acceleration, up to 45 per cent of available torque can be transferred to the rear wheels; in hard cornering during acceleration, up to 70 per cent of available torque can be directed to the rear wheels for enhanced vehicle dynamics.
And up to 100 per cent of the torque sent to the rear axle can be applied to either rear wheel as the conditions dictate.

Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Acura RDX. Click image to enlarge

The system is remarkably effective. We’ve driven the RDX in severe winter conditions and the driver’s feeling of connectedness to the road is noteworthy. Of course, as a performance-oriented vehicle, the RDX is designed with superior handling in mind, and obviously this contributes to its overall feeling of balance and stability. But the performance of the RDX in deep snow, on ice, and in generally slippery conditions inspires confidence beyond what one would expect from most SUV-type vehicles.

The RDX is not invincible, of course, but where most drivers are visibly experiencing difficulty on poor surfaces, so far our RDX has been unfazed. The tires certainly have a role to play in this. Shod with Michelin X-Ice Latitude winter tires, you can actually feel them bite into ice and snow, especially when braking. In contrast, reliable, straight-line acceleration from a standstill is mainly a result of the AWD and traction control systems, though the winter tires surely optimize these technologies.

Today, another battle: at the time of this writing, there’s a transit strike in our town, which is increasing traffic volume by up to 20 per cent. We’ve just absorbed another major storm, and the side streets in many cases have not been cleared while equipment is focused on maintaining major roads. Tempers are short; delays can be long. The RDX is proving to be a major asset.

2009 Kia Sportage LX-V6 Luxury

By Grant Yoxon

Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Kia Sportage LX-V6 Luxury. Click image to enlarge

Ottawa, Ontario – You may recall from our last report that the 2009 Kia Sportage LX-V6 Luxury performed well in deep snow, but on slippery roads a lack of lateral adhesion while cornering would quickly prompt intervention from Kia’s standard Electronic Stability Control (ESC) system; and stopping, though straight and confident, was usually accompanied by anti-lock brake (ABS) chatter.

Being equipped with the original equipment Kumho all-season tires, I had to wonder if winter tires might not improve overall performance.

Since then the Sportage has had a tire change and now sports General Altimax Arctic winter tires. And as suspected, the winter tires make a big difference.

Now the Kia corners much better. Performance in deep snow is only marginally better, but on slippery or slushy roads it takes a bit of effort to set off the ESC while cornering and stopping has dramatically improved.

How different winter driving aids work together is not well understood by many owners of all-wheel drive vehicles. All-wheel drive can make a dramatic improvement in the way a vehicle moves away from rest and accelerates in slippery conditions, but it has little effect on how the vehicle stops. Inspired by the sure-footed traction of all-wheel drive and traction control, over-confident drivers tend to over-drive their vehicle and get in trouble when it comes time to stop.

Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Kia Sportage LX-V6 Luxury. Click image to enlarge

As well, all-wheel drive doesn’t necessarily improve cornering, although it certainly changes the behaviour of the vehicle. While a rear-wheel drive vehicle will over-steer when it loses traction in a turn (the rear end will slide out and try to overtake the front), and a front-wheel drive car will tend to under-steer such that the car doesn’t turn in and ploughs straight off the road, an all-wheel drive vehicle can slide sideways on all four wheels in what is known as a four-wheel drift.

All-wheel drive offers great benefits for winter driving, but it is not the only winter traction aid you need. When it comes to driving in dangerous conditions, the full arsenal of winter traction aids – all-wheel drive, traction control, ESC, ABS and, of course, winter tires – work together to keep you safe.

And with winter tires, the Kia Sportage has the full arsenal.

Its “Torque on Demand (TOD)” all-wheel drive is a relatively simple system. Always active while driving, sensors constantly monitor wheel speed, vehicle speed and steering wheel angle. If any of these sense a slipping condition at the front wheels, torque is automatically transferred to the rear wheels.

TOD uses an inline coupler consisting of a wet clutch pack. The clutches are drawn together via an electromagnetic coil. The strength of the electromagnet is dependent on the amount of slip detected. The greater the electromagnet strength, the closer the clutches are pulled together resulting in increased torque transfer.

Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
Feature: Bring it on! 2009 Acura RDX and 2009 Kia Sportage, Part Two kia acura
2009 Kia Sportage LX-V6 Luxury. Click image to enlarge

The Sportage can also be locked into permanent four-wheel drive with torque split 50/50 between the front and rear by pressing a button on the dash. The fixed torque transfer will remain active up to 40 km/h – perfect for churning through deep snow – when it will disengage to save fuel. If left in the locked position, the fixed torque split will re-engage when speed drops below 40 km/h.

The second weapon in the anti-winter arsenal, electronic stability control, is the most important, because it can save your life. ESC combines the ABS and traction control systems and adds additional sensors monitoring yaw, lateral acceleration and steering angle and calculates what manoeuvres the driver intends to perform and whether the vehicle threatens to skid off course. In this case, ESC reacts as fast as lightning and selectively applies braking pressure at each wheel and adjusts engine rpm to “steer” the vehicle in the desired direction.

That ESC intervened less frequently with the winter tires tells us that the vehicle gets better traction with winter tires than with all-season tires.

The third weapon is ABS brakes which allow the driver to maintain steering control when stopping. When the wheels stop turning so does your ability to steer. ABS prevents wheel lock-up and uncontrolled skidding under braking. That we experienced less ABS intervention with the winter tires also tells us that the General Altimax Arctic tires were giving us better traction under braking than the all-season tire.

The Kia Sportage has all the tools to get going and keep going when winter driving gets tough. And with a price ranging from $25,895 to $30,935 when equipped with all-wheel drive, one doesn’t need to break the bank for winter driving safety.

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