The BMW M88 is a straight-6

DOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...

petrol engine A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as ' ...

which was produced from 1978 to 1989. It is based on the DOHC version of the BMW M49 engine, which was used in the BMW 3.0CSi racing cars. The M88 was produced alongside the

BMW M30 The BMW M30 is a SOHC straight-six petrol engine which was produced from 1968 to 1995. With a production run of 27 years, it is BMW's longest produced engine and was used in many car models. The first models to use the M30 engine were the BMW 25 ...

engine, as the higher performance engine. In North America up until 1989, the

BMW S38 The BMW S38 is a straight-6 DOHC petrol engine which replaced the M88 and was produced from 1984-1995. The S38 was originally produced for North America as an equivalent to the M88 with slightly lower power output. In 1989, power output of the S3 ...

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

valvetrain on a production engine for the first time on the M88, with the camshafts driven by a single-row

timing chain In a piston engine, either a timing belt (also called a ''cambelt'') or timing chain or set of timing gears is used to synchronize the rotation of the crankshaft and the camshaft. This synchronisation ensures that the engine's valves open and cl ...

Kugelfischer Kugelfischer injection (also called ''System Kugelfischer'') is the name for a mechanical fuel injection (MFI) pump. It was produced by FAG Kugelfischer and later by Robert Bosch GmbH Derived from diesel pumps from the early 1960s, the Kugelfisch ...

fuel injection was used with individual

throttle A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engine's power can be increased or decreased by the restriction of inlet gases (by the use of a throttle), but usually decreased. The term ''throttle'' ...

valves and the distinctive six individual throttle bodies. The construction is an aluminium

cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern ...

and a cast iron

block Block or blocked may refer to: Arts, entertainment and media Broadcasting * Block programming, the result of a programming strategy in broadcasting * W242BX, a radio station licensed to Greenville, South Carolina, United States known as ''96.3 ...

. The bore is and the stroke is , resulting in a

displacement Displacement may refer to: Physical sciences Mathematics and Physics * Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

of .

Versions

M88

The M88 was the original iteration of the engine and was fitted to the BMW M1. It produces at 6,500 rpm and at 5,500 rpm. A

dry sump A dry-sump system is a method to manage the lubricating motor oil in four-stroke and large two-stroke piston driven internal combustion engines. The dry-sump system uses two or more oil pumps and a separate oil reservoir, as opposed to a con ...

is used. Applications: * 1978-1981 M1

M88/1

For the BMW M1 Procar single-make series, the M88 engine was bored out marginally to reach . This racing version, called the M88/1, met the

Group 4 Group 4 may refer to: *Group 4 element, chemical element classification *Group 4 (racing), classification for cars in auto racing and rallying * G4S, formerly Group 4 Securicor, a prominent British security company *IB Group 4 subjects The Group 4 ...

regulations. This race engine produced in Procar specifications. This version had forged pistons, sharper camshafts, bigger valves, as well as oil cooling for the transmission and rear differential. Applications: * 1979-1980 Procar BMW M1

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 , which with the 1.4 turbo factor placed it in the 4.5-liter class. This race engine produced up to . Applications: *

Group 5 Group 5 may refer to: *Group 5 element, chemical element classification *Group 5 (racing) Group 5 was an FIA motor racing classification which was applied to four distinct categories during the years 1966 to 1982. Initially Group 5 regulations def ...

racing cars

M88/3

The M88/1 engine was modified for use in the E24 M635CSi and E28 M5 and was known as the M88/3. The

fuel injection was replaced with Bosch

Motronic Motronic is the trade name given to a range of digital engine control units developed by Robert Bosch GmbH (commonly known as Bosch) which combined control of fuel injection and ignition in a single unit. By controlling both major systems in a si ...

producing at 6,500 rpm and at 4,500 rpm. 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. 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

engine family. Different years of this engine uses both Bosch

and Bosch

L-Jetronic Jetronic is a trade name of a manifold injection technology for automotive petrol engines, developed and marketed by Robert Bosch GmbH from the 1960s onwards. Bosch licensed the concept to many automobile manufacturers. There are several variation ...

engine management systems. 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 A catalytic converter is an vehicle emissions control, exhaust emission control device that converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalysis, catalyzing a redox chemic ...

and produced . Applications: * 1979-1981 E12 M535i * 1978-1982 E24 635CSi * 1978-1982 E23 735i

References

{{DEFAULTSORT:Bmw M88 M88 World Sportscar Championship engines Straight-six engines Gasoline engines by model