Alpina takes a unique approach to performance. Rather than sacrificing itself at the altar of handling, the tuning house takes a more relaxed approach, putting comfort before hot-lap dominance. The latest product of that formula is the BMW 5 Series-based D5 S, the fastest diesel production car in the world.
At the core of the D5 S is a three-liter inline-six diesel engine, tuned to feel rev-happier than the average diesel engine. Most do their best work low in the rev range, delivering big slugs of torque with little fanfare, so delivering a diesel that wants to chase the redline is no easy task.
The D5 S offers peak power of 388 hp (285 kW) between 4000 and 5000 rpm, and peak torque of 800 Nm (1,328 lb-ft) is on tap between 1,750 and 2,650 rpm. The sprint from 0-100 km/h (62 mph) is dealt with in 4.4 seconds, and the 286 km/h (178 mph) top speed elevates the D5 S to world's fastest diesel status.
This performance is, according to Alpina, down to a combination of clever air intakes, two-stage management of boost from the engine's three turbochargers and a high-performance cooling system. Along with the large volume coolers and indirect intercooler, there are three external coolers and a dedicated gearbox oil cooler to make sure things stay cool at full noise. Not that owners are likely to care, the car sips just 6.6 l/100km (36 mpg) on the combined cycle.
To make sure all that clever diesel engineering doesn't turn the D5 S into a beautifully built missile at speed, Alpina has borrowed the chassis from the B5 Bi-Turbo and adapted it for the diesel. Adaptive dampers developed by Bilstein are standard fitment, and stiffer springs help lower the center of gravity for sharper changes in direction. The D5 S Touring comes with rear air springs, designed to keep the same ride height when the boot is loaded up.
Depending on the option boxes ticked, the car can be optioned with rear-wheel steering for sharper low-speed handling and a more stable ride at high speed. Included with the rear-wheel steering system is roll stabilization, capable of actively stiffening the suspension for a flatter ride through the corners. The standard xDrive all-wheel drive system has a distinct rear bias, and allows the driver to get a little bit sideways with stability control turned off.
From the outside, the D5 S is unmistakably an Alpina. The low, squared-off front splitter is a staple of the company's design, while the forged 20-inch wheels help save weight and look predictably gorgeous. Down back, you get quad exhaust pipes and a body-colored diffuser to differentiate the car from regular BMW models. You also get unique readouts for the digital driver display, and there's a multitude of stitching options for the rich leather seats. If you have enough time and money, essentially any combination of colors, materials and dashboard trim finishes is available.
Pricing for the D5 S will start at €87,900 (US$106,000). The car will debut at the Frankfurt Motor Show, which kicks off next week.