Quattro was made famous by Audi over ten years ago. After using it to dominate motorsports, they incorporated versions of it into its road cars, culminating with the torsen-based system found on the Audi A4. The system has changed gradually over the years, moving from a 50:50 torque split to a rear-biased 40:60. Torque vectoring was added in with the debut of the S4 sedan last year. Now at the Geneva Auto Salon, Audi debuted it’s new Quattro system that uses a new center differential. This is significant because Audi stayed with the Torsen center diff from 1996 all the way until this year. Whether this new diff gets put into the regular series of cars or remains an RS-exclusive remains to be seen.

The new center diff is explained in the video below, and also goes over the torque vectoring concept. The RS5 and S4 both come with torque vectoring, and is also seen on the new 2010 Porsche Carrera Turbo.

BMW hosted an event called BMW Comparison Drive. At the event, BMW allowed us to compare their 3 series (323i, 328i xDrive, 335i xDrive and 335d Diesel) against the all-wheel drive versions of the Audi A4, Lexus IS 250 and Mercedes-Benz C300. It was a  cloudy day, but the track was dry – it threatened to rain but never did.

The event started with a 30 minute presentation about BMW and the various technologies they use. Not much new information was conveyed but the information was very pro-BMW. However, they did a good job and all the information was based on facts. Since they were comparing all the all-wheel drive cars, it’s important to note that the BMW xDrive cars cannot be equipped with sport suspension. This is unlike cars like the Audi A4 which can be equipped with lowered sport suspension which improves it’s handling and dynamics.

The short track was designed to test dynamics and not powertrain performance. Noone needed to leave 2nd gear at any part of the circuit. The course had five sections, starting with a long sweeping turn with a decreasing radius near the end. Following was an emergency braking while turning exercise, an emergency lane change, and a slalom through the cones. The final leg was a full throttle then full braking exercise.

All the BMW’s felt very good in the course, but the 323i was underpowered. It would be a great commuter car but anyone after some serious performance should pass this car over. The 328i performed great, but it was hard to notice the AWD in this course. A wet traction section would show it off some more, especially since BMW bragged that it was the only system that could put 100% of the power to either front or rear axles.

Some of my observations:

• The BMW’s interior is too stark, although the quality of materials is top notch, sitting in the Audi and Mercedes felt a lot better. It was about on par with the Lexus.
• The Lexus IS250 AWD is too burdened with the automatic transmission and AWD drivetrain to be a fun car. A manual IS250 without AWD would be more fun.
• The Mercedes has a great sounding exhaust, and it was only the C300. The C350 must sound fantastic.
• ABS braking is life-saving technology. And every car performed both braking maneuvers flawlessly and some had less aggressive touring tires.