Unlike traditional brake-biased systems, S-AWC centers around a four-wheel-drive controller that links to the five dynamic components of any vehicle: engine, transmission, brakes, steering, and suspension. This four-wheel-drive controller is an updated version of the current ACD/AYC system. The rest of S-AWC is a host of new sensors and switches, along with Active Braking and Active Steering systems.
Sensors play a big role in both the ACD/AYC and S-AWC systems. ACD/AYC has eight of them, including four that measure individual wheel speed and ones for steering angle, throttle opening, and longitudinal and lateral acceleration. S-AWC incorporates all of these and adds seven more, including a yaw-rate sensor, an additional steering-angle sensor (for Active Steering), and five for measuring brake pressure (at each wheel and on the brake pedal).
Active Braking uses the information gathered by these sensors as a means to support ACD/AYC in instances of aggressive driving. It's not to be confused with ABS, and while it functions similarly to stability control systems, the overall purpose of Active Braking is different. Stability control serves to keep the car planted in hairy instances, such as slides and spins. Mitsubishi claims Active Braking assists driver operation in order to improve dynamic performance. Its goal is for Active Braking to realize the driver's intent (via the sensors) and provide assistance (via improved, state-of-art hydraulics). Mitsubishi says if the driver intends to drift or rotate the car, the system will support it. How this system differentiates between an intended and unintended drift or spin wasn't specified, however.
As you might expect, Active Steering is not as simple as the standard variable steering systems that employ a quick ratio at low speeds with a progressively slower one as speeds increase. Mitsubishi claims Active Steering will improve response to steering operation under normal driving conditions (under relatively low lateral acceleration) and assist counter steering in tricky driving conditions. This augmented steering angle (driver's steering angle + Active Steering angle) is used in conjunction with ACD/AYC and Active Brake "so more precise and quicker handling response can be realized by synergy effect of integrated S-AWC."
Sound complicated? It is. But the basic concept is not hard to grasp: S-AWC is Mitsubishi's attempt to assist the driver's intentions (via ACD/AYC and Active Braking and Steering) based on data collected at the steering wheel, throttle, and brakes and compared against the car's actual dynamic condition (as measured by the wheel speed, yaw rate, and longitudinal and lateral acceleration sensors). Is it any good? Based on the test mule we drove, we're going to have to say ... not yet. The S-AWC system was surprisingly rough, but did show flashes of brilliance.
The mule we drove was a yellow Evo VIII stuffed with the all the aforementioned electronics. Powered by the older, MIVEC-less 4G63 engine, the car felt noticeably less powerful than the two other Evos. Except for engine output, however, every aspect of the handling mule seemed to be steroid enhanced. In less than spirited situations, the car felt fine. Pushing the car, however, put it into a hyperactive state that was difficult to handle. The active steering was particularly over-boosted and artificially exaggerated the quickness of the rack with none of the current model's precision. The brakes were equally amped up, with an instant-on feel when the driving conditions got hairy. Throughout my laps on the handling course I could feel something going on at the wheels of the car, but exactly what was hard to determine and distracting.
The oddest characteristic occurred during the hard, slow corners-such as the rapid U-turn after the slalom. Turning hard to the left shifted the weight to the right and naturally lifted the inside rear wheel. When I got back on the throttle at the exit of the turn, that wheel felt like it was spinning free-the opposite of what you'd want or expect from a complicated all-wheel-drive system. It was a bit disconcerting to find that all the electronics had only succeeded in making the mule drive like it had an open rear differential.
Then I had an opportunity to drive with the Active Steering and Active Braking systems turned off, and this made a world of difference. Much of the JDM Evo IX came back, including the predictable steering and braking. The difference in the ACD/AYC however, was a matter of refinement; of course the Evo IX felt better, but that goes without saying when comparing mules to full-production cars.
Obviously the system is not done yet. Dr. Evo wouldn't say how much more development is needed, but my guess is the S-AWC system we drove could not be more than 60-percent complete. Despite its rough edges, however, I found the whole experience exciting and a good omen for the X.
There is currently a lot of talk among Mitsubishi fans mourning the death of the current Evo. While it's natural to fear change, especially with a legend like the Evolution, it is heartening to see that Dr. Evo and his crew are taking risks and being bold. To them, the current Evo is not some hero to be worshipped, but rather a jumble of old technology that they are anxious to improve upon. The next-generation Evo will be entirely new, and those opportunities do not come very often. Yes, Dr. Evo knows how much you love the Evo, but he's on a mission to build a better one.
The Price Of Admission: Mitsubishi OutlanderWhat's this? An SUV reviewed in the pages of Sport Compact Car? Well, the price of admission for seat time in the Evo X handling mule was the promise that we'd at least mention we drove the soon-to-be released second-generation Mitsubishi Outlander. After all, it was the whole reason Mitsubishi schlepped us all the way out to Nagoya.