Alpina, which has been tuning BMWs for years, has come up with a competitor to the new M5. It develops the same amount of power, reaches 60 mph in 4.7 seconds and has a top speed of 195 mph – Alpina does not believe in 155 mph limiters for its cars. As a result, it claims this is the world’s fastest production sedan – and not many people would argue.

Heart of the BMW Alpina B5 – based on the 5 Series, like the M5 – is BMW’s 4.4 liter V-8. BMW’s M Division does without turbos and superchargers. Not Alpina; they have adopted a centrifugal compressor, engine driven, to boost power throughout the speed range and produce the same power ouput as the BMW V-10.

Bu the system has a neat twist. At idling and when driving at low speed, the compressor does not operate, so gas mileage is quite good. A throttle plate upstream of the supercharger cuts it in and out according to load.

Mighty powerful with 500 bhp

This is a mighty powerful engine; at 2,500 rpm it develops 200 bhp, and ramps up to 500 bhp at only 5,500 rpm, so the character of the engine is completely different from BMW’s V-10. Thanks to the supercharger, there’s massive torque over a big range, with the maximum of 516 lb ft available from 4,250 to 5,250 rpm – terrific mid-range power. Read the rest of this entry »