| BMW M88 engine | |
|---|---|
 | |
| Overview | |
| Manufacturer | BMW |
| Also called |
|
| Production | 1978–1989 |
| Layout | |
| Configuration | Straight-6 |
| Displacement | 3.5 L (3,453 cc) |
| Cylinder bore | 93.4 mm (3.7 in) |
| Piston stroke | 84 mm (3.3 in) |
| Cylinder block material | Cast iron |
| Cylinder head material | Aluminium |
| Valvetrain | DOHC (M88) SOHC (M30B35LE/M90) |
| Combustion | |
| Fuel type | Petrol |
| Chronology | |
| Predecessor | None |
| Successor | BMW S38 |
TheBMWM88 is astraight-6DOHCpetrol engine which was produced from 1978 to 1989. It is based on the DOHC version of the BMW M49 engine, which was used in theBMW 3.0CSi racing cars.[1][2][3]
The M88 was produced alongside theBMW M30 engine, as the higher performance engine. In North America up until 1989, theBMW 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 aSOHC engine which is based on the M88/1; this is sometimes referred to as the M90.
BMW engineers used aDOHC valvetrain on a production engine for the first time on the M88, with thecamshafts driven by a single-rowtiming chain.[4]Kugelfischer fuel injection[5] was used with individualthrottle valves[6] and the distinctive sixindividual throttle bodies.
The construction is an aluminiumcylinder head and a cast ironblock.[7][8] Thebore is 93.4 mm (3.68 in) and thestroke is 84.0 mm (3.31 in), resulting in adisplacement of 3,453 cc (210.7 cu in).
| 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[9][10] | up to 625–735 kW (850–1,000 PS; 838–986 hp) at 9,000 rpm | 847–1,017 N⋅m (625–750 lb⋅ft) at 7,000 rpm[11] | 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/M90 | 160 kW (218 PS; 215 hp) at 5,200 rpm | 304 N⋅m (224 lb⋅ft) at 4,000 rpm | 1978–1982 | SOHC |
The M88 was the original iteration of the engine and was fitted to theBMW M1. It produces 277 PS (204 kW; 273 hp) at 6,500 rpm and 330 N⋅m (240 lb⋅ft) at 5,500 rpm. Adry sump is used.[12]
Applications:
For the BMW M1Procar single-make series, the M88 engine was bored out marginally to reach 3,498 cc (3.5 L). This racing version, called theM88/1, met theGroup 4 regulations. This race engine produced 350 kW (480 PS; 470 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:
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 (910 PS; 900 hp).[13]
Applications:
The M88/1 engine was modified for use in theE24 M635CSi andE28 M5 and was known as the M88/3.[14] TheKugelfischerfuel injection was replaced withBoschMotronic producing 210 kW (290 PS; 280 hp) at 6,500 rpm and 340 N⋅m (250 lb⋅ft) at 4,500 rpm.[15] It has acompression ratio of 10.5:1.
The M88/3 was also fitted to the South African BMW 745i, due to packaging problems with the turbochargedM102 engine which was used in other markets.[16]
Applications:
TheM30B35LE is a lower performance, two-valve,SOHC version of the M88/1 engine, also known as theM90. It utilizes the same block as the M88 and maintains the same bore and stroke, but borrows its head from theBMW M30 engine family. Depending on year, this engine uses either BoschMotronic or BoschL-Jetronic as its engine management system.[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 engine used a compression ratio of 9.3:1, did not have acatalytic converter, and produced 160 kW (220 PS; 210 hp).
Applications: