Mazda's all-wheel-drive vehicles are designed to engage the driver with a sense of total control, making driving more than just getting from A to B.
Mazda vehicles are known to be particularly sporty and a pleasure to drive, whether the hot MX-5 roadster, one of the brand’s popular Mazda3 sedans or hatchbacks, or any of its trio of crossover utility models. Its products are designed to engage the driver, to make him or her feel totally in control and to make driving more than just getting from A to B.
So when an all-wheel drive system was added to the mix as Mazda’s CUV/SUV lineup developed, engineers focused on creating a system that stayed true to the Mazda mantra, ensuring precise control and sporty dynamics.
To demonstrate that the Mazda i-ACTIV all-wheel drive system has achieved those goals, the company invited a group of automotive journalists to the 2016 Mazda Ice Academy where a series of courses were laid out on an icy plateau nestled between the mountains of a popular ski resort at Crested Butte, Colorado.
Mazda was hoping for snow at this event – and Mother Nature didn’t disappoint. The worst snowstorm of the winter dumped nearly three feet (90-plus centimetres) of the white stuff in a day and a half, making it extremely difficult to stick to the event agenda. Some of the planned activities had to be abandoned, such as a street drive with the CX-5 and competitive vehicles, due to the near-zero visibility.
The heavy snowfall did, however, create optimum conditions to test the i-ACTIV AWD system. The AWD vehicle lineup consisted of the 2016 CX-5 and the recently introduced 2016 CX-3, as well as some competitive products.
Mazda’s innovative AWD system is built around its SKYACTIV-Drive six-speed automatic transmission, which is linked to a lightweight, high-strength propeller shaft with a dynamic damper that reduces noise, vibration and harshness. The size of the rear differential has been reduced, compared to previous units, with an aluminum case that’s just 2.5 millimetres thick. The Power Takeoff Unit in the rear differential and the differential gear size have been minimized through detailed analysis of gear stress.
As a result, the weight of the complete unit has been reduced significantly – the CX-5’s rear differential weighs just 51 kilograms, compared to the 89-kg unit in the CX-7. The new CX-9, which will be hitting the streets later this year, has a 54-kg unit, compared to the current model’s 80-kg package. The new on-demand design delivers a seamless delivery of power, while internal friction has been reduced so much the fuel efficiency is comparable to front-wheel-drive models.
The i-ACTIV AWD is an on-demand system, rather than full-time AWD. While the latter type system does have the advantage of a centre differential, allowing even torque split while the front and rear wheels can still rotate at different speeds, it does result in higher driveline loss and, consequently, lower fuel efficiency. The full-time system also requires a longitudinal layout with the engine hanging out ahead of the front axle, creating a nose-heavy weight distribution that adversely impacts handling. The on-demand system generates less driveline loss in two-wheel mode (which is used most often) and it can be packaged more efficiently.
Typically, on-demand systems allow a moment of wheel slippage before engaging; they also restrict the front and rear wheels from turning at different speeds when torque is transferred to the rear wheels. Mazda engineers countered these disadvantages by developing a system that anticipates, rather than reacts to changing conditions so torque is transferred to the rear wheels before the wheels start to slip. The system uses 27 channels of data from onboard sensors to analyze conditions 200 times a second – from windshield wiper position and outside temperature to steering angles and effort. All the data comes from pre-existing sensors already in the vehicle, with one exception – the sensor added to monitor differential oil temperature.
The i-ACTIV system was noticeably superior to those of the competitive vehicles in the hill-climb exercise, which required them to climb a grade, then stop at the crest. Before advancing, the front wheels were turned hard right and then the vehicle was free to proceed down the grade. The CX-5 handled the challenge without a problem, engaging all four wheels to make the sharp turn. The competition, a Honda CR-V and a Subaru Forester, were less capable – both failing to activate the rear wheels on the restart. In fact, the Honda couldn’t muster enough traction to complete the maneuver, while the Subaru eventually found enough grip to get down the hill.
The autocross/slalom course also demonstrated the superiority of the Mazda AWD system. Again, the CX-5 was pitted against the CR-V and Forester. The precise control the Mazda engineers strived for in developing the system was evident in this exercise, with the CX-5 making seamless shifts from two-wheel to all-wheel drive as conditions dictated. Entering corners or weaving through the pylons, its precise turn-in capabilities gave me a sense of control and confidence. The CR-V felt more vague running through the course, while the Subaru, although quite adept at making the moves, did so with a more effort than the Mazda – and its control systems generated significance noise as they adjusted to the conditions.
Mazda partnered with Bridgestone Tires in this event, with that company supplying its WS80 Blizzak winter tire for the vehicles. One of the modules of the Ice Academy was a comparison between all-season tires and winter rubber. Identical CX-3s were used for this exercise and although one anticipated the winter tires would be superior, the degree of difference was surprising. Drivers were required to launch from a standstill and accelerate through a course of pylons before approaching a braking box. The sequence was repeated on that lap, then we switched to the other vehicle and did it all again.
The first surprise was the noticeable difference in grip when launching the vehicle – the Blizzaks immediately grabbed with minimal spin while the all-season tires churned for several seconds before the vehicle started moving. On the run through the course, the all-seasons slipped noticeably in the turns, especially an off-camber corner, while the winter tires stayed true to the course. Braking was a no-brainer, with the Blizzaks stopping sooner as expected. The surprise, however, was how much shorter the distance required to stop was compared to the all-season tires – consistently with each driver in our group, the all-season-equipped CX-3 slid an additional 12-13 metres before coming to a stop. That’s a distance that could easily be the difference between stopping safely or suffering a crash, injury or worse.
This event wasn’t all work – Mazda tossed in a bit of fun as well. The crew had worked for six weeks prepping the site with a thick ice base. Thoughtfully, their efforts included building a large skid pad – and Mazda added the finishing touch by providing a clutch of MX-5 roadsters. No, they didn’t have i-ACTIV AWD, but they did promise the ultimate dose of pure driving fun. Actually, it was a bit surprising to discover how well these sporty two-seaters can cope with such adverse conditions. While most MX-5 owners have their gems tucked away for the winter, we were invited to toss our fleet around on the icy, snow-laden autocross layout like kids with a new toy.
The exercise did demonstrate that the outstanding balance built into the MX-5 enables the driver to fling the car about while still feeling in complete control. That said, with the amount of snow piled up on the ice base, “control” was something that slipped away quickly – and frequently. It was, however, a total blast – the top down, snow blowing all around and visibility next to nil. What more could a driving enthusiast desire? For me, it was the highlight of the event.
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