The M3 is a 3-series like no other. Created by BMW's M-for-Motorsport division, it has an enviable reputation for performance and handling. The original M3 (E30) was a pure bred special providing 195bhp from 2.3 litres and four cylinders. Despite only being built in left hand drive, many believed it to be the best handling and most rewarding saloon BMW had produced to date. It grew into something more remarkable still. Evo editions added another 35 bhp as well as numerous enhanced body panels and suspension and became one of the finest driver's cars on the planet. In 1993 it was superseded by the bigger and heavier M3 (E36). Although a lot 'plusher' the agility and precision of the previous generation had been lost, and in 1996 BMW offered a 321bhp 3.2 litre engine to entice disgruntled M3 aficionados back. Finally, came the E36 M3 Evo which improved the situation still further.
The E46 M3 follows the tradition more of the E30 than the E36 and has seen the BMW Motorsport division produce an outstanding road car. First introduced in October 2000 with the new 3.2 litre engine which had the highest specific output of any naturally aspirated engine ever made by BMW, producing 343 PS (338 hp) and 370 N•m (269 ft•lbf). The model also came with a new 6-speed transmission and red-line RPM of 8000, a first for any BMW. The engine also consisted of 6 independent throttle bodies and electronically driven throttles (without a cable). At the time recognised as one of the greatest driving cars BMW had ever produced it amassed fantastic reviews in the motoring press.
“This is truly a defining car for BMW. It is closer in driving character to the original M3 and delivers true super-car performance.” Autocar
"Drive it for a day and you'll be amazed by the immediacy of its responsiveness and by the sheer explosiveness of its straight line performance. You'll soon start to wonder why anyone else would bother trying to build a rival to such a car" Autocar
"BMW have launched themselves into a new class, invading Ferrari/Porsche high ground" CCC magazine
“The most versatile and accomplished all-round performance car on the market" Auto Express
"The ride is a delight, look for passengers climbing out with wild eyes and puckered cheeks, or drivers wearing silly grins long after they have parked BMW's fastest-accelerating M yet". Driven
"The people who work at BMW Motorsport won't settle for second best. It shows in the M3. In the perfection of its form, the fine resolution of its details and the depth of its engineering" Evo
"A match for all but the fleetest of supercars - The quickest M car BMW have ever built" Car
"It's the pulling power that really impresses. A maximum of 269lb ft is offered at 4900rpm, which not only provides effortless overtaking potential, but also makes the M3 a doddle to drive in town, with 6th gear happy to pull from 1500rpm" What Car
The M3 Variable M Differential
The engineers at BMW M, teaming up with specialists at GKN Viscodrive GmbH, have developed an all-new differential system for the new BMW M3 - the Variable M Differential Lock. This lock offers decisive advantages in traction even in very demanding driving situations, for example when there is an extremely large difference in frictional coefficients on the drive wheels. Accordingly, the Variable M Differential Lock enables the new BMW M3, in combination with the fine-tuned DSC system and the car's perfect front-to-rear balance, to offer a standard of driving excellence and handling in winter previously regarded as quite impossible with a rear wheel-drive sports car. Maintaining Drive Power and Thrust In Every Situation A further advantage of the Variable M Differential Lock is the increase in locking forces parallel to any increase in differential speed between the drive wheels. As a result, a wheel suddenly relieved of its load and drive force - for example the inner wheel in a corner while driving fast on a mountain pass - can no longer make drive forces "collapse" entirely. Instead, drive power and the car's forward thrust are always maintained at an appropriate level.
The Variable M Differential Lock functions according to a simple principle: The difference in rotational speed that builds up between the two drive wheels whenever one of the drive wheels loses grip, either because it has become unloaded or hit a slippery surface, generates pressure spontaneously in an integrated shear pump. This pressure is then conveyed via a piston to a multiple-plate clutch, thereby channeling power to the wheel with better grip. In an extreme case, the entire drive power of the engine may be transmitted to the wheel with better grip (provided that enough grip exists). Once the difference in wheel rotation speed between the two wheels becomes smaller, pump pressure is reduced accordingly and locking action decreases. This self-controlled pump system is maintenance free and is filled with highly viscous silicon oil. The big advantage for the driver of the BMW M3 is the ability to accelerate far better on surfaces with dramatically different levels of grip between the two drive wheels, since there is now more traction available. In addition the Variable M Differential Lock noticeably improves both handling and driving stability, thus elevating safety and driving pleasure to a new, unprecedented level of excellence.(source AutoWorld.com )