Thursday, 7 February 2013

History of "M" and M5

The "M" subsidiary of BMW was started in 1972 to facilitate BMW's racing program. Over time, BMW M began to supplement BMW's vehicle portfolio with specially modified sports models for sale to the consumer.

The first such M car available for public purchase was the M1 in 1978 which was the product of an agreement with Lamborghini.

It used a straight 6 with dual overhead cam shafts, individual throttle bodies for each cylinder, and mechanical fuel injection (a complex 3-dimensional cam controlled the flow of fuel under varying conditions). The base engine made 273 HP, but turbocharged racing versions were capable of producing 850 HP.

 The M1, however, was more a racecar than an everyday driver. Only 456 were ever built.

The immediate predecessor to the M5 was the Motorsport E12 M533i in 1978, followed by the M535i in 1979 (the "i" stands for "fuel injection" as opposed to carburated).

It used a variant of the same engine as the M1, but fitted to the original E12 5-Series body. Only about 1400 were ever produced. Its engine, also a straight 6, displaced 3.45L and made 215HP and 224ft-lb of torque at 4000rpm.

Its successor was the first car named "M5", based on the E28 body.

For a time it was the world's fastest production car. The European spec car used a different variant of the inline 6 M1 engine, made 282 HP, had a curb weight of 3400 lbs, and had a 0-60 mph time of 6.2s.

The next M5 was the E34 M5 first produced in 1988.

It continued to use an inline 6 cylinder engine rated at 311 HP, later enlarged and upgraded to 335 HP. This car was the first M5 that I saw parked on the street. It had a curb weight of 3860 lbs and went from 0-60 mph in 5.7s in the larger engine version, which would be roughly equivalent to the performance of my 2005 BMW 545i.

The E39 M5 introduced in 1998 was the first widely successful M5, and is also considered by many as the finest of the M5's to date.

This car had a V8 engine, made 394 HP, had a curb weight of just over 4030 lbs and had a 0-60 mph time of 4.8s.

The E60 M5 introduced in 2005 was a bit of a departure. It was very inspired by BMW's involvement with F1 in developing the 10 cylinder P83 engine used by the 2003 BMW-Williams F1 racing team in its FW25 racecar.

This was a 10 cylinder, 4 valve per cylinder, 90 degree V10 lightweight aluminium engine displacing 3.0 L, making greater that 900 HP, revving to 19,200 RPM, and weighing less than 200 lbs. The car weighs only 1320 lbs in total and goes from 0-60 mph in under 2s. Its transmission was the Williams 7-Speed longitudinal semi-automatic sequential.

The E60 M5 inspired by this car had a 5.0 L high-revving (8120 RPM redline) 10 cylinder naturally aspirated engine making 500 HP. The car had a curb weight of 4090 lbs, and went from 0-60 mph in 4.1s.

The car was designed for the SMG III sequential manual gearbox which itself was very inspired by F1 technology. The car received praise on the track, but suffered on the road because of its lack of low-end torque, the lack of smoothness of its transmission, its small gas tank, and its relatively high fuel consumption.

The torque/HP curves compare the E60 M5 to the new F10 M5. Particularly at the low end, around 1500 RPM, the E60 has only 70% of the torque of the F10, whereas all the F10 torque comes on at very low RPM due to the presence of its turbochargers.

For all of these reasons, I held off on my M5 purchase until the F10 M5 arrived.

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