BMW E24 635 CSI M6 - 50 Years of BMW M cars

Date: 15.04.2022

A mere four years after the M1 came the M635 CSi, introduced at the 1983 Frankfurt Motorshow.

The M635 CSI, or M6 as it was marketed in North America and Japan, was the pinnacle of the E24 coupe range and a genuine Grand Tourer in every sense.

Iconic BMW designer Paul Bracq was responsible for the sublime body shape and further developed the driver-facing dash giving the E24 a unique interior look and ambience.

Most aficionados agree the big four-seater coupe was one of the Bavarian car makers finest efforts, with its distinctive nose, prominent kidney grille, large glass area, low waistline and flowing silhouette.

Setting the M635 CSI apart was its striping, distinctive BBS cross spoke wheels, deep front spoiler and another smaller one on the boot lid.

Timeless two-door coupe still turns heads

The E24 was a significant model and record holder for the longest production life (13 years) in the company history. While the shape remained much the same over that period, there were myriad changes under the skin.

Many consider the M635 CSI was ahead of its time and subtlely fused high performance motoring with ultimate luxury for its occupants.

While the rest of the E24 range made do with a six-cylinder M30 engine the M635 CSI was powered by the 3.5-litre M88 straight six, 24-valve engine (the same as in the M1) developed by BMW Motorsport.

The luxo coupe could boogie too

To achieve its 210kW@6500rpm power and 340Nm@4500rpm torque numbers, the straight six engine ran a 10.5:1 compression ratio, modified Bosch Jetronic fuel injection and tweaked ignition. Top speed was 255km/h and zero to 100km/h took just 6.4 seconds.

Its sporting character demanding a five-speed transmission, a limited slip differential and naturally rear wheel drive.

The M635 CSI chassis was also given the Motorsport magic with larger stabilisers and beefier shock absorbers working with the MacPherson strut front and independent semi-trailing arm rear suspension. And to improve weight distribution the battery was mounted in the boot.

Pulling up the 1500kg Beemer is accomplished with 300mm vented front discs and 284 mm rears.

It wasn’t until 1987 the American and Japanese markets got the car badged M6.

Under the bonnet was an S38 straight six with a catalytic converter due to emissions laws. This sapped power to 191kW, down 22 on its European equivalent.

To suit American tastes the M6 was lavishly appointed with heated power seats, self-leveling rear suspension, a beverage chiller (cooled by the air-conditioning system) between the rear seats, air-conditioning vents for rear seat occupants, sunshades for rear occupants and an 8 speaker premium sound system. Most of these were optional in other markets.

Six of the best

Like the M3 that followed it, the E24 series was always destined for competition and anyone who watched touring car racing in the 1980s will vividly remember the black and gold JPS BMWs driven by Frank Gardner, Jim Richards and Alan Grice.

Richards won his and BMW’s first Australian Touring car crown aboard a 635 CSI in 1985 as well as capturing the 1985 and ‘86 Australian Endurance Championships.

Big ways to read gauges

Elsewhere the 6 series won the European Touring Car championship on three occasions, along with the German, Belgian, Japanese and New Zealand touring car crowns. It also took out the 24 hour race at Spa three times and the Nürburgring on two occasions. Over its production run from 1983 through 1989, 5855 M635 CSi/M6 cars were built with 1767 sent to North America.

Today the M635 CSI is highly prized by BMW enthusiasts and the most sought of all E24 coupes.

50 Years of BMW M cars:

Part one - BMW M1

Part two - BMW E30 M3

Part four - BMW E39 M5

Part five - BMW 1M

Part six - Z3 M coupe

From Unique Cars #462, March 2022

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