Future Auto Technologies · 27 July 05

With the debut of BMW’s new 3 series comes new technologies other automobile manufacturers will undoubtedly imitate. These technologies include:

*Cast aluminum brake calipers

*Composite magnesium/aluminum engine block

*Forged aluminum suspension components

*Electro/hydraulic speed sensitive steering system

Why are these technologies important? Let me start with the aluminum brake calipers. Almost all “mass produced” vehicles on the road use cast iron calipers. Since the primary function of braking systems is to convert kinetic energy to thermal energy, the use of a superior heat-dissipating material (aluminum) in the braking system will improve performance. Another advantage of aluminum over iron is weight. Typical cast iron calipers weigh an average of 12lbs. The new calipers on the 3 series weigh 7lbs for a savings of 5lbs of unsprung weight.

BMW didn’t stop the unique metal usage with the brakes. Instead, BMW used its Formula 1 engine building expertise and made the new engine block of the 330i sedan out of a sandwich of magnesium and aluminum. The new N52 powerplant is good for 255bhp and 220lb-ft of torque. BMW achieved a weight savings of 22lbs over the old powerplant (the M54).

To further save weight on the new 3 series, BMW used aluminum for the suspension components as well as the steering rack. The rear uses a new 5 link system with better freedom of movement. The combination of lighter sprung and un-sprung weight on the 330i have given the sedan an almost perfect 50/50 weight distribution.

While not exactly new for BMW, the new electric/hydraulic steering system in the 3 series is a step forward in car control department. The system basically uses extra hydraulic pressure only when necessary (like hunting for a parking space). As speed increases, hydraulic pressure decreases causing the steering feel to tighten up. An added bonus of having an electric system is that the engine no longer has to drive a steering pump. This system helps reduce parasitic losses created by belt driven accessories (the new N52 only uses one accessory belt vs. 2 for the M54).

With the use of lighter materials in manufacturing the new 3 series, BMW has managed to create a new sedan that is 2.2in longer, 3.0in wider, and taller by .8in while adding less than 100lbs. The result: better handling, quicker acceleration, and more room.