The BMW M88 is a straight-6 DOHC petrol engine which was produced from 1978-1989. It is based on the DOHC version of the BMW M49 engine, which was used in the BMW 3.0CSi racing cars.[1][2][3]

The M88 was produced alongside the BMW M30 engine, as the higher performance engine. In North America up until 1989, the BMW S38 engine was used instead of the M88. In 1989, an updated version of the S38 became the worldwide replacement for the M88. The M30B35LE is a SOHC engine which is based on the M88/1; this is sometimes referred to as the M90.

Design

BMW engineers used DOHC valvetrain on a production engine for the first time on the M88, with the camshafts driven by a single-row timing chain.[4] Kugelfischer fuel injection[5] was used with individual throttle valves[6] and the distinctive six individual throttle bodies.

The construction is an aluminium cylinder head and a cast iron block.[7][8] The bore is 93.4 mm (3.68 in) and the stroke is 84.0 mm (3.31 in), resulting in a displacement of 3,453 cc (210.7 cu in).

Versions

Engine code Power Torque Years Note
M88 204 kW (277 PS; 273 hp)
at 6,500 rpm
330 N⋅m (243 lb⋅ft)
at 5,000 rpm
1978-1981 BMW M1
M88/1 346 kW (470 PS; 464 hp)
at 9,000 rpm
390 N⋅m (288 lb⋅ft)
at 7,000 rpm
1979-1980 Gr.4 Procar
M88/2 up to 625 kW (850 PS; 838 hp)
at 9,000 rpm
1979-1981 Gr. 5 turbo
M88/3 210 kW (286 PS; 282 hp)
at 6,500 rpm
340 N⋅m (251 lb⋅ft)
at 4,500 rpm
1983–1989 M635 CSi, M5, 745i (South Africa only)
M30B35LE 160 kW (218 PS; 215 hp)
at 5,200 rpm
304 N⋅m (224 lb⋅ft)
at 4,000 rpm
1978–1982 SOHC

M88

M88/1 with some parts replaced with Plexiglas for display purposes

The M88 was the original iteration of the engine and was fitted to the BMW M1. It produces 204 kW (277 PS; 273 hp) at 6,500 rpm and 330 N⋅m (243 lbf⋅ft) at 5,500 rpm. A dry sump is used.[9]

Applications:

  • 1978-1981 M1

M88/1

For the BMW M1 Procar single-make series, the M88 engine was bored out marginally to reach 3,498 cc (3.5 L). This racing version, called the M88/1, met the Group 4 regulations. This race engine produced 470 PS (350 kW; 460 hp) in Procar specifications. This version had forged pistons, sharper camshafts, bigger valves, as well as oil cooling for the transmission and rear differential.

Applications:

M88/2

For Group 5 racing, the M88 engine was turbocharged and became known as the M88/2. It was downsleeved and had a shorter stroke to displace 3,191 cc (3.2 L), which with the 1.4 turbo factor placed it in the 4.5-liter class. This race engine produced up to 670 kW (900 hp).[10]

Applications:

M88/3

M88/3 iteration used in the E24 M635CSi and E28 M5.

The M88/1 engine was modified for use in the E24 M635CSi and E28 M5 and was known as the M88/3.[11] The Kugelfischer fuel injection was replaced with Bosch Motronic producing 210 kW (286 PS; 282 hp) at 6,500 rpm and 340 N⋅m (251 lbf⋅ft) at 4,500 rpm.[12] It has a compression ratio of 10.5:1.

The M88/3 was also fitted to the South African BMW 745i, due to packaging problems with the turbocharged M102 engine which was used in other markets.[13]

Applications:

  • 1983-1989 E24 M635CSi
  • 1984-1987 E28 M5
  • 1984-1987 E23 745i (South Africa only)

M30B35

The M30B35LE is a lower performance, two-valve, SOHC version of the M88/1 engine, also known as the M90. It utilizes the same block as the M88 and maintains the same bore and stroke, but borrows its head from the BMW M30 engine family. Different years of this engine uses both Bosch Motronic and Bosch L-Jetronic engine management systems.[5] Typically identified by a white L painted on the block behind the oil filter housing and coolant water passages on the side of the block.

As sold in Europe and most other markets (except North America), this used a compression ratio of 9.3:1, did not have a catalytic converter and produced 160 kW (218 PS; 215 hp).

Applications:

See also

  • BMW S14 - Four-cylinder engine based on the M88

References

  1. ^ "The Story of 40 Years BMW M ‒ The BMW M1". gtspirit.com. Retrieved 13 December 2018.
  2. ^ "Top 5 Great BMW Engines". mydriftfun.com. 11 May 2017. Archived from the original on 15 December 2018. Retrieved 13 December 2018.
  3. ^ "M Division's Greatest Competition Engines – Infernal Combustion". Infernalco.co. 20 March 2018. Retrieved 31 May 2021.
  4. ^ Horatiu Boeriu (24 May 2012). "Chris Harris Drives the E28 BMW M5". Bmwblog.com. Retrieved 31 May 2021.
  5. ^ a b "M1 Technology". Projectm1.com. Retrieved 31 May 2021.
  6. ^ "Engine FAQ". Bimmerforums.com. 23 August 2009. Retrieved 31 May 2021.
  7. ^ "1984 BMW 745i E23 5-Speed manual M88 engined SA model road test". drive-my.com. Retrieved 2 December 2018.
  8. ^ "BMW M88 and S38 M-Tech 24 Valve Six Cylinder Engines". unixnerd.demon.co.uk. Retrieved 2 December 2018.
  9. ^ "The BMW Six Cylinder Guide". autospeed.com.
  10. ^ "Archived copy". Archived from the original on 13 July 2012. Retrieved 15 August 2012.CS1 maint: archived copy as title (link)
  11. ^ "Archived copy". Archived from the original on 23 October 2013. Retrieved 15 August 2012.CS1 maint: archived copy as title (link)
  12. ^ "FAQ E24 M635CSi + M6". BMW M Registry. Retrieved 31 May 2021.
  13. ^ "FAQ E23 745i SA (M88)". BMW M Registry. Retrieved 31 May 2021.