BMW 6 Series (E24)

BMW 6-Series (E24)
BMW 633 CSi
Overview
Manufacturer	BMW
Production	1976–1989 86,216 built[1]
Assembly	Dingolfing, West Germany Rheine, West Germany
Designer	Paul Bracq[2] Manfred Rennen
Body and chassis
Class	Grand tourer (S)
Body style	2-door coupé
Layout	FR layout
Powertrain
Engine	2.8−3.5 L six-cylinder petrol
Transmission	Manual 4-speed 5-speed Automatic 3-speed 4-speed
Dimensions
Wheelbase	2,626 mm (103.4 in)
Length	4,755 mm (187.2 in) 4,923 mm (193.8 in) (US bumpers)
Width	1,725 mm (67.9 in)
Height	1,365 mm (53.7 in) 1,354 mm (53.3 in) (M6)
Curb weight	1,450 kg (3,200 lb) 1,583 kg (3,490 lb) (L6) 1,619 kg (3,569 lb) (M6)
Chronology
Predecessor	BMW E9
Successor	BMW 8 series BMW E63

The E24 BMW 6 Series grand tourer was produced/sold by German automaker BMW (Bayerische Motoren Werke) from 1976 to 1988 (1989 in the US) model years. After a 16-year hiatus, the 6-Series reappeared with the 2004 E63 6 Series.

Model history

The E24 was a replacement for the CS and CSL coupés first produced in 1965. The 3.0 CS was almost changed by adding a few centimeters in height to make it easier for customers to get into the car. However, Bob Lutz rebelled against the decision and rough drafted an alternative version that soon became the 6 series.^[3] Production started in March 1976 with two models: the 630 CS and 633 CSi. Originally the bodies were manufactured by Karmann, but production was later taken in-house to BMW.

In July 1978 a more powerful variant, the 635 CSi, was introduced (for the time being not available in North America and Japan) that featured as standard a special close-ratio 5-speed gearbox and a single piece black rear spoiler. The bigger bore and shorter stroke facilitated max 218 hp at 5200rpm and a better torque curve. For the first year, the 635 CSi was offered in three colors (Polaris, Henna Red, Graphite), and could also be spotted by the front air dam that did not have attached fog lights. These simple cosmetic changes reportedly worked to reduce uplift on the car at high speeds by almost 15% over the non-spoiler body shape. This early model shared suspension components with the inaugural BMW 5-series, the E12.

In 1979 the carburetted 630 CS was replaced with the 628 CSi; this car had a fuel injected 2.8L engine taken from the BMW 528i.

In 1980 the 635 CSi gained the central locking system that is also controlled from the trunk. Also, the E24 body style converted from L-jetronic injection to a Bosch Motronic DME.

In 1982 (Europe) and 1983 (US), the E24 changed slightly in appearance, with an improved interior and slightly modified exterior. At the same time, the 635 CSi received a new engine, a slightly smaller-bored and longer-stroked 3430 cc six to replace the former 3453 cc engine and became available with a wide-ratio 5-speed manual or an automatic.

1984–86 BMW 635 CSi

This slight change in 1982 (Europe) was in fact a major change as pre-1982 cars were based on the E12 5-series chassis; after mid-1982, e24s shared the improved E28 5-series chassis. The only parts that remained the same were some of the exterior body panels. This fact can be verified by studying the parts lists.

E24s produced after June 1987 came with new, ellipsoid headlamps which projects beam more directly onto road surface (newly introduced E32 7-series also sporting them).^[4] The sleeker European bumpers were also discontinued. Previous cars had either a European-standard bumper or a larger, reinforced bumper to meet the US standard requiring bumpers to withstand impact at 5 mph (8 km/h) without damage to safety-related components. 1989 was the last year for the E24 with production stopping in April. The E24 was supplanted by the considerably heavier, more complex, and more exclusive 8 Series (E31).

M version

BMW M88 engine of the M 635 CSi

BMW Motorsport introduced the M 635 CSi in Europe at the Frankfurt Motor Show in 1983. It is essentially an E24 powered by the powerplant of the BMW M1 - the M88 (286 PS (210 kW; 282 hp)). Most of the cars were equipped with special metric 415 mm diameter wheels requiring Michelin TRX tires. A catalyzed, lower compression ratio version of the car with the S38 engine (260 PS (190 kW; 260 hp)) was introduced in the U.S. in 1987. All M6 cars came standard with a 25% rear limited slip differential. U.S. models included additional comforts that were usually optional on models sold in Europe such as Nappa leather power seats and a dedicated rear A/C unit with a center beverage chiller. Car and Driver tested a U.S. M6 in July 1987 and achieved a 0-60 time of 6.1 seconds, better than the BMW published 6.4 and 6.8 second times for the European and U.S. versions respectively. 4,088 M 635 CSi cars were built between 1983 and 1988 with 1,767 U.S. M6 built.^[5]

Technical data

Manufacturer's figures except where stated.^[1] (does not include North American and Japanese models).

BMW	628 CSi	630 CS	633 CSi	635 CSi	635 CSi	M 635 CSi
Produced:	1979–1987	1976–1979	1976–1983	1978–1988	1988–1989	1983–1989
Engine:	M30B28	M30B30	M30B32	M30B34	M30B35	M88/3
Max. Power @ rpm:	184 PS (135 kW; 181 hp) @ 5800	185 PS (136 kW; 182 hp) @ 5800	197 PS (145 kW; 194 hp) @ 5500	218 PS (160 kW; 215 hp) @ 5200	218 PS (160 kW; 215 hp) @ 5200	286 PS (210 kW; 282 hp) @ 6500
Max. Torque @ rpm:	235 N·m (173 lb·ft) @ 4200	255 N·m (188 lb·ft) @ 3500	284 N·m (209 lb·ft) @ 4300	304 N·m (224 lb·ft) @ 4000	304 N·m (224 lb·ft) @ 4000	333 N·m (246 lb·ft) @ 4500
Fuel tank capacity:	70 L (18.5 US gal; 15.4 imp gal)
Gearbox:	4-speed manual, from 1979 5-speed manual (wide- or close-ratio) on request 3-speed automatic, from 1983 4-speed automatic rear wheel drive					5-speed manual rear wheel drive
Front suspension:	MacPherson strut axle, coil springs, stabilising bar
Rear suspension::	Trailing arms, struts, coil springs, stabilising bar
Steering:	ZF recirculating ball steering, power assisted
Dry weight:	1,450 kg (3,200 lb)	1,475 kg (3,252 lb)	1,495 kg (3,296 lb)	1,520 kg (3,350 lb)	1,470 kg (3,240 lb)	1,510 kg (3,330 lb)
Track front/ rear:	1,422 mm (56.0 in) 1,487 mm (58.5 in)	1,422 mm (56.0 in) 1,487 mm (58.5 in)	1,422 mm (56.0 in) 1,487 mm (58.5 in)	1,430 mm (56 in) 1,460 mm (57 in)	1,430 mm (56 in) 1,460 mm (57 in)	1,430 mm (56 in) 1,464 mm (57.6 in)
Wheelbase:	2,626 mm (103.4 in)	2,626 mm (103.4 in)	2,626 mm (103.4 in)	2,626 mm (103.4 in)	2,626 mm (103.4 in)	2,626 mm (103.4 in)
Top speed:	215 km/h (134 mph)	210 km/h (130 mph)	215 km/h (134 mph)	222 km/h (138 mph)	225 km/h (140 mph)	255 km/h (158 mph)

NOTE: The 1978–1981 635 CSi utilized a 3453cc M90 engine not shown here.

Models for North America and Japan

While in most markets several E24 versions were usually available, markets with strict emission control regulations received only a single model (except for the M6 that was later offered additionally). This meant that in North America and Japan, BMW offered the following models:^[6]

1980s US market 635 CSi, rear view

• 630 CSi (MY 1977 through 1978½)
• 633 CSi (MY 1978½ through 1984)
• 635 CSi (MY 1985 through 1989)
• L6 (MY 1987 - Luxury Edition 635 CSi NA-only)
• M6 (MY 1987 through 1989)

In 1977, the 6 series was released in the US as the 630 CSi. This was a fuel-injected version of the carburetted 630 CS available elsewhere. Its 3-litre engine developed 176 hp (131 kW) and 185 lbf·ft (251 N·m) of torque.

In mid-model year 1978 the 630 CSi was replaced by the 633 CSi, which lasted until 1984. US/Japan specification 633 CSi cars had the M30 3.2-litre 181 hp (135 kW) engine. Output later dropped to 174 hp (130 kW). Until the 1981 model year, when a five-speed manual finally replaced it, US-market cars had a four-speed manual as standard (with an optional three-speed automatic).^[7] In 1985 the car was renamed 635 CSi, displacement was increased to 3.4 litres and horsepower increased slightly to 182 hp (136 kW). The big difference, however, was torque. Whereas the 3.2-litre had 195 lbf·ft (264 N·m) at 4,000 rpm, the 3.4 litre powerplant managed 214 lbf·ft (290 N·m) at 4,000 rpm.

From model year 1983, North American and Japanese versions benefitted from the technical revisions and changes to the interior introduced elsewhere in spring or summer 1982. Its chassis was now based on the E28 and no longer on the E12. The front and rear suspension was also revised. Later a self-levelling rear suspension was added to the 635 CSi and M6 features list in 1988.^[6]

1988 BMW M6. Note the 5mph bumper.

The US received its own M series E24 in 1987 called the M6. The S38 powerplant found in the US model had several modifications from the M88 powerplant in the European model, most notably: a double row timing chain, modified cam tray, different valve lengths, a slightly different cam profile, less elaborate exhaust manifold (rather than full headers), Bosch X5DC copper spark plugs (instead of Bosch Silver plugs on the M88) and the introduction of an oxygen sensor for the EFI. These changes coupled with the introduction of a catalytic converter for emission regulations reduced the output to 256 hp (191 kW). The US model also included a variety of options usually available on European models, to include: heated power seats, sport tuned self-levelling rear suspension, A/C cooled ice box between the rear seats, A/C vents for rear seat occupants, sunshade for rear occupants and an 8 speaker "premium" sound system.

In 1988, the US E24 was now available with the newest version of the M30, the 3.4L (first used in the E32 735i). Even though the intake manifold states 3.5 it's technically a 3.4 (3430cc) like the previous 3.4. This engine had an increased compression ratio, and updated Motronics/DME. The result was 208 hp (155 kW) and 225 lbf·ft (305 N·m) torque. In effect, this engine was identical to the catalyzed version newly available in Germany and other markets.^[6]

Significant victories in auto racing

Championships & Series

• European Touring Car Championship; 3 titles (1981, 1983 and 1986)
• Deutsche Tourenwagen Meisterschaft; 1 title (1984)
• Belgian Touring Car Championship (Group N); 1 title (1984)
• Australian Touring Car Championship; 1 title (1985)
• Australian Endurance Championship; 2 title (1985 and 1986)
• Australian Manufacturers' Championship; 1 title (1985)
• AMSCAR Series; 1 title (1985)
• European Hill Climb Championship; 1 title (1985)
• New Zealand Touring Car Championship; 2 titles (1985 and 1987)
• New Zealand Benson&Hedges Saloon Car Series; 1 title (1985)
• Japanese Touring Car Championship; 1 titles (1985)

Races

• RAC Tourist Trophy; 2 wins (1980 and 1984)
• 4h/500km of Monza; 3 wins (1980, 1981 and 1983)
• Guia Race; 1 win (1983)
• Spa 24 Hours; 3 wins (1983, 1985 and 1986)
• 24 Hours Nürburgring; 2 wins (1984 and 1985)

References

1. Oswald, Werner (2001). Deutsche Autos 1945-1990, Band 4 (in German). Stuttgart: Motorbuch Verlag. ISBN 3-613-02131-5.
2. References:
   • Norbye, Jan P. (1984). "Exciting Elegance: The 6-Series and 7-Series". BMW - Bavaria's Driving Machines. Skokie, IL: Publications International. p. 220. ISBN 0-517-42464-9. The main attraction was an all-new bodyshell with handsome, contemporary, very clean lines penned by the artistic Paul Bracq.
   • Severson, Aaron (February 13, 2010). "Status-Seeking Missiles: The BMW E24 6-Series Coupes". Ate Up With Motor. Aaron Severson. Retrieved 2014-05-08. The E24′s exterior was designed under the auspices of Paul Bracq, a former Daimler-Benz stylist who replaced Wilhelm Hofmeister as director of design in 1970. BMW also commissioned an alternative proposal from Giorgetto Giugiaro’s Italdesign, but the board eventually selected Bracq’s in-house proposal.
   • Lewin, Tony. "Moving on up". The Complete Book of BMW: Every Model since 1950. St. Paul, MN US: Motorbooks International. p. 111. ISBN 0-7603-1951-0. Retrieved 2014-05-14. Under the skin – Paul Bracq's design, chosen over a rival proposal from Italy's fashionable Giorgio Giugiaro – lay familiar BMW engineering elemsnts from the 5 Series updated to suit the new era.
3. Lutz, Robert A. (2003). Guts: 8 Laws of Business from One of the Most Innovative Business Leaders of Our Time. Wiley and Sons. Retrieved 2010-12-02.
4. "1987 BMW 6-Series coupe | Theory | BMW E24". E-24.ru. Archived from the original on 24 October 2010. Retrieved 2010-11-10.
5. "FAQ E24 M635CSi/M6". BMW M Registry. Archived from the original on 22 September 2010. Retrieved 2010-10-03.
6. Covello, Mike (2002). Standard Catalog of Imported Cars 1946-2002. Iola, WI USA: Krause Publications. ISBN 0-87341-605-8.
7. Hogg, Tony (ed.). "1981 Buyer's Guide". Road & Track's Road Test Annual & Buyer's Guide 1981 (January-February 1981): 84.

External links

• The UnixNerd's BMW E24 site within a site 10 pages of photos, history, buying guides and common problems.