Engineering:BMW 7 Series (E23)

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BMW 7 Series (E23)
Bronzit1.jpg
Overview
Production1977–June 1986[1]
285,029 built[2]
Assembly
DesignerPaul Bracq, Manfred Rennen
Body and chassis
ClassFull-size luxury car (F)
Body style4-door sedan/saloon
LayoutFR layout
Powertrain
Engine
  • 2.5–3.2 L M30 I6
  • 3.2 L M102 turbo I6
  • 3.4 L M106 turbo I6
  • 3.5 L M90 I6
  • 3.5 L M88/3 I6
Dimensions
Wheelbase2,795 mm (110.0 in)[4]
Length
  • 4,860 mm (191.3 in)[4]
  • 5,014 mm (197.4 in) (US spec)
Width1,800 mm (70.9 in)[4]
Height1,430 mm (56.3 in)[4]
|uk|Kerb|Curb}} weight1,470–1,629 kg (3,241–3,591 lb)
Chronology
PredecessorBMW E3
SuccessorBMW 7 Series (E32)
Rear view
Check Control panel: query of operating fluids, function of the rear lights
Interior, post facelift
Pre-facelift with the first grille and earlier mirrors

The BMW E23 is the first generation of the BMW 7 Series luxury cars and was produced from 1977 until 1986. It was built in a 4-door sedan body style with 6-cylinder engines, to replace the BMW 'New Six' (E3) sedans. From 1983 until 1986, a turbocharged 6-cylinder engine was available.

In 1986, the E23 was replaced by the E32 7 Series, however, the E23 models (called L7) remained on sale in the United States until 1987.

The E23 introduced many electronic features for the first time in a BMW, including an on-board computer, service interval indicator, a "check control panel" (warning lights to indicate system faults to the driver), a dictaphone and complex climate control systems.[5][6] It was also the first BMW to offer an anti-lock braking system (ABS),[7][8] a driver's airbag (optional, starting in April 1985[9][10]) and a new design of front suspension.[11]

Development and production

The initial styling concepts were developed under BMW Design Director Paul Bracq,[12] with Manfred Rennen contributing with the exterior styling.[13]

Production occurred from 1977 until 1986,[1] during which time 285,029 cars were built.[2]

Engines

All models were powered by a straight-six petrol engine, with the majority of cars using the BMW M30 engine. Most engines were fuel-injected, however the 728 and 730 models of 1978–1979 used a Solex four-barrel carburetor. The fuel-injected models initially used the Bosch L-Jectronic system, until the 1979 732i, which was the first BMW to use the Bosch Motronic fuel-injection system.[14]

Model Years Engine Power Torque Notes
725 1977–1979 2.5 L M30
carb
110 kW (150 PS)
at 6,000 rpm
211 N⋅m (156 lb⋅ft)
at 3,700 rpm
725i 1981–1986 2.5 L M30
injected
110 kW (150 PS)
at 5,800 rpm
215 N⋅m (159 lb⋅ft)
at 4,000 rpm
For government agencies
& special order only[2][15]
728 1977–1979 2.8 L M30
carb
125 kW (170 PS)
at 5,800 rpm
233 N⋅m (172 lb⋅ft)
at 4,000 rpm
728i 1979–1986 2.8 L M30
injected
135 kW (184 PS)
at 5,800 rpm
240 N⋅m (177 lb⋅ft)
at 4,200 rpm
[16]
730 1977–1979 3.0 L M30
carb
135 kW (184 PS)
at 5,800 rpm
255 N⋅m (188 lb⋅ft)
at 3,500 rpm
732i 1979–1986 3.2 L M30
injected
145 kW (197 PS)
at 5,500 rpm
285 N⋅m (210 lb⋅ft)
at 4,300 rpm
[16]
733i (EU) 1977–1982 145 kW (197 PS)
at 5,500 rpm
279 N⋅m (206 lb⋅ft)
at 4,300 rpm
733i (US) 1978–1979 132 kW (179 PS; 177 hp)
at 5,500 rpm
266 N⋅m (196 lb⋅ft)
at 4,000 rpm
United States & Japan only
1980–1981 129 kW (175 PS; 173 hp)
at 5,200 rpm
255 N⋅m (188 lb⋅ft)
at 4,200 rpm
1982–1984 135 kW (184 PS; 181 hp)
at 6,000 rpm
264 N⋅m (195 lb⋅ft)
at 4,000 rpm
735i (EU) 1979–1982 3.4 L M90
injected
160 kW (218 PS)
at 5,200 rpm
304 N⋅m (224 lb⋅ft)
at 4,000 rpm
[16]
1982–1986 3.4 L M30
injected
160 kW (218 PS)
at 5,800 rpm
310 N⋅m (229 lb⋅ft)
at 4,000 rpm
735i (US),
L7 (US)
1985–1987 3.4 L M30
injected
136 kW (185 PS; 182 hp)
at 5,400 rpm
290 N⋅m (214 lb⋅ft)
at 4,000 rpm
United States & Japan only
745i (EU) 1980–1982 3.2 L M102
turbo
185 kW (252 PS)
at 5,200 rpm
380 N⋅m (280 lb⋅ft)
at 2,600–4,000 rpm
[16]
1983–1986 3.4 L M106
turbo
185 kW (252 PS)
at 4,700 rpm
380 N⋅m (280 lb⋅ft)
at 2,200 rpm
[17]
745i (SA) 1984–1986 3.5 L M88/3
injected
210 kW (286 PS)
at 6,500 rpm
340 N⋅m (251 lb⋅ft)
at 4,500 rpm
South Africa only

Transmissions

The available transmissions consisted of:

Equipment

Options included leather upholstery, wood trim, power seats, seat heaters, reclining rear seats, power windows, power mirrors, an in-car cellular telephone and rear-armrest radio controls (only with the executive and highline pack ).[10][9]

Yearly changes

1983 facelift

Post-facelift model with revised grille and black mirrors

The 1983 model year facelift (produced from September 1982) included styling changes to the front of the car: wider and more angular 'kidney' grilles, valance/spoiler, bumper bars, etc. Inside the car, the dashboard and instrument panels were also updated. The rear suspension was updated and the 735i engine changed from the M90 to the M30B34.

1984

In the US, 1984 saw the arrival of the optional 4-speed automatic transmission[18] (replacing the 3-speed unit previously offered), wood trim replacing the plastic above the glove compartment and on the ashtray and electrically adjustable power seats. Michelin TRX tyres (requiring special metric wheels) became available as an option on the 5-speed manual models.

Special models

725i

The 725i model was not officially sold but produced for West German government agencies which, at the time, were not allowed to have engines larger than 2.5 liter in official cars. 921 models were produced.[19]

Turbocharged 745i

745i model- rear view

The 745i was a high-performance model sold in left-hand-drive European markets from 1979 to 1986. It was initially powered by the M102 engine, which is a turbocharged 3.2 L version of the M30 straight-six engine, producing 185 kW (248 hp; 252 PS) at 9 PSI of boost.[20] In 1982, the engine was upgraded to the M106, which increased the capacity to 3.4 litres and the fuel injection system changed from Jetronic to Motronic. Boost pressure was reduced to 6 PSI,[21] however power output was unchanged.

All M102 cars were built with a 3-speed ZF 3HP22 automatic transmission. All M106 cars were built with a 4-speed ZF 4HP22 automatic transmission.[21][22] Options included heated front and rear power reclining seats, gasoline fired heater, leather covered cellular telephone, rear-armrest radio control, water buffalo hide upholstery, and burl wood trim.

The name 745i comes from the theoretical assumption that turbocharged engines have approximately 1.4 times more power than naturally aspirated engines. By this assumption, a 3.2 litre (3205 cc) turbocharged engine would have similar power to a 4.5 litre (4487 cc) naturally aspirated engine.

South African 745i

The South Africa n 745i model was powered by the naturally aspirated M88/3 engine, instead of the turbocharged M102/M106 engines of the European 745i. A right-hand-drive version of the turbocharged model was not possible due to the turbocharger being located in the right-hand side of the engine bay. Instead, the 745i was fitted with the 210 kW (280 hp; 290 PS) M88/3 engine, as used in the E24 M635i and E28 M5. The engine uses a 24-valve DOHC valvetrain and the fuel injection system is Bosch ML-Jetronic.

A production run of 192 South African 745i was built from 1983 to 1987, 175 of which were with an automatic gearbox and 17 with a 5-speed manual gearbox.[23][24]

BMW South Africa entered one of these 745i models in Class A of the South African Modified Saloon Car Championship The 745i won the championship in 1985,[25] the only BMW-Sanctioned motorsport application in the history of BMW 7 Series cars.[26]

United States and Japanese market models

E23 in U.S.
U.S. model rear, including elongated bumpers

Only the 733i, 735i, and L7 models were sold in the United States and Japan.[27] These markets also received only upscale versions, usually including leather upholstery, cruise control, wood trim, power windows, power sunroof, and other options as standard.

North American versions were fitted with larger bumpers (to comply with the U.S. National Highway Traffic Safety Administration (NHTSA) standards), smaller sealed beam headlights, and various forms of emissions equipment that were not found on European-market cars. The engines used in these markets had lower-compression pistons and thus were less powerful than European-market versions. Some features such as ABS were available in markets outside North America before they were fitted on American models.

The L7 was a more luxurious version of the 735i for the American market only.[28] It featured special leather upholstery with leather dashboard and door padding (rather than wood trim), a power glass Moonroof, and a variety of optional features as standard. All L7 models were built with automatic transmissions and a standard driver's air bag.

References

  1. 1.0 1.1 Vijayenthiran, Viknesh (29 July 2007). "BMW 7-series turns 30". https://www.motorauthority.com/news/1026847_bmw-7-series-turns-30. Retrieved 7 May 2020. 
  2. 2.0 2.1 2.2 Oswald, Werner (2001) (in German). Deutsche Autos 1945–1990, Band 4 (1. ed.). Stuttgart: Motorbuch Verlag. ISBN 3-613-02131-5. 
  3. World Cars 1980, pages 340-341
  4. 4.0 4.1 4.2 4.3 "Fahrbericht: BMW 728 / 730 / 733 i" (in de). Auto, Motor und Sport 11 1977: 34–42. 25 May 1977. 
  5. "The BMW E23 7-Series". http://www.autospeed.com/cms/article.html?&title=The-BMW-E23-7Series&A=2031. Retrieved 25 January 2017. 
  6. "BMW 7 Series (E23) – 1977 – 1986" (in en-us). http://www.autoevolution.com/cars/bmw-7-series-e23-1977.html#aeng_bmw-7-series-e23-1977-725-3at-150-hp. Retrieved 25 January 2017. 
  7. Denton, Tom (June 2007). Automobile Electrical and Electronic Systems. p. 390. ISBN 9781136427756. https://books.google.com/books?id=Z0hOBZTStoQC. Retrieved 25 January 2017. 
  8. "History of Brakes in Motor Cars / Automobiles" (in en-gb). http://www.carhistory4u.com/the-last-100-years/parts-of-the-car/brakes. Retrieved 25 January 2017. 
  9. 9.0 9.1 "BMW 7 Series – A Look Back" (in en). http://www.topspeed.com/cars/car-news/bmw-7-seriesa-look-back-ar168860.html. Retrieved 25 January 2017. 
  10. 10.0 10.1 "The first BMW 7 Series – E23". 9 November 2014. http://www.bmwblog.com/2014/11/09/first-bmw-7-series-e23/. Retrieved 25 January 2017. 
  11. Taylor, James (26 October 2015) (in en). BMW M5: The Complete Story. Crowood. ISBN 9781785000461. https://books.google.com/books?id=exWbCgAAQBAJ. Retrieved 25 January 2017. 
  12. Caspers, Markus (2017) (in en). Designing Motion: Automotive Designers 1890 to 1990. Birkhäuser. p. 80. ISBN 9783035607840. https://books.google.com/books?id=B9UXDQAAQBAJ&pg=PA80. Retrieved 18 June 2018. 
  13. "BMW car designers". https://www.bmwism.com/bmws_designers.htm. 
  14. "BMW M30 and M102 Six Cylinder Engines". http://www.unixnerd.demon.co.uk/m30.html. Retrieved 25 January 2017. 
  15. "1981 BMW E23 7 Series 725i Technical Specs" (in en). https://www.ultimatespecs.com/car-specs/BMW/1421/BMW-E23-7-Series-725i.html. Retrieved 9 December 2018. 
  16. 16.0 16.1 16.2 16.3 BMW AG (ed.): Betriebsanleitung 728i 732i 735i 745i, 2nd edition, August 1982, p. 166+167
  17. BMW AG (ed.): Betriebsanleitung 728i 732i 735i 745i, 3rd edition, April 1983, p. 173
  18. "Road test 1985 BMW 735i E23". https://drive-my.com/en/test-drive/item/2201-road-test-1985-bmw-735i-e23.html. Retrieved 3 March 2017. 
  19. "Luxus und Eleganz: 30 Jahre BMW 7er Reihe." (in de). https://www.press.bmwgroup.com/switzerland/article/detail/T0029502DE/luxus-und-eleganz:-30-jahre-bmw-7er-reihe?language=de. 
  20. "The BMW Six Cylinder Guide". http://www.autospeed.com/cms/article.html?&title=The-BMW-Six-Cylinder-Guide&A=2948. Retrieved 24 January 2017. 
  21. 21.0 21.1 "BMW 745i E23 Turbo". http://www.uniquecarsandparts.com.au/car_info_bmw_745i_turbo.htm. 
  22. "Rmfd. automatic transmission". http://www.realoem.com/bmw/enUS/part?id=6941-EUR-03-1980-E23-BMW-745i&mg=24&sg=05&diagId=24_0036&q=24001208983. Retrieved 25 January 2017. 
  23. "FAQ E23 745i SA (M88)". http://www.bmwmregistry.com/model_faq.php?id=4. 
  24. (in en) Inside BMW Group Classic - the weirder side of luxury, with the BMW 7 series., https://www.youtube.com/watch?v=yNHa6T-pEww?t=48, retrieved 2023-05-11 
  25. "3½ Decades of BMW Motorsport in South Africa". https://drive-my.com/en/sport/92-3-decades-of-bmw-motorsport-in-south-africa.html. Retrieved 10 March 2017. 
  26. "BMW 745i SA -The M7 You Never Knew Existed". http://www.topspeed.com/cars/car-news/bmw-745i-sathe-m7-you-never-knew-existed-ar169229.html. Retrieved 10 March 2017. 
  27. "BMW 7'E23 model selection". http://www.realoem.com/bmw/enUS/select?product=P&archive=1&series=E23&body=Lim. Retrieved 20 February 2017. 
  28. "The Bavarian Luxo barge: A look back at the BMW 7-series". http://autoweek.com/article/classic-cars/history-bavarian-plutobarge-look-back-bmw-7-series. Retrieved 20 February 2017. 

Footnotes