Removed text is struck through; added text is highlighted.
BMW automotive engine families listed as M20. Specifications below retain the source's separate family and variant labels.
Family specifications
BMW M20 engine
FieldReported valueProduction1977–1993ConfigurationStraight-6Displacement2.0 L (1,991 cc) 2.3 L (2,316 cc) 2.5 L (2,494 cc) 2.7 L (2,693 cc)Cylinder bore80 mm (3.15 in) 84 mm (3.31 in)Piston stroke66 mm (2.60 in) 75 mm (2.95 in) 76.8 mm (3.02 in) 81 mm (3.19 in)Cylinder block materialCast ironCylinder head materialCast aluminum alloyValvetrainSOHCFuel typePetrolPredecessorNoneSuccessorBMW M50
Variant specifications
Models
VersionDisplacementPowerTorqueBoreStrokeCompression RatioYearsNotesM20B201,991 cc (121.5 cu in)90 kW (122 PS; 121 hp) at 6,000 rpm163 N⋅m (120 lb⋅ft) at 4,000 rpm80 mm (3.15 in)66 mm (2.60 in)9.2:11977-1982Solex 4A1 variantM20B201,991 cc (121.5 cu in)92 kW (125 PS; 123 bhp) at 5,800 rpm170 N⋅m (125 lb⋅ft) at 4,000 rpm80 mm (3.15 in)66 mm (2.60 in)9.0:1 (catalyst) 9.8:1 (non-catalyst)1982-1984L-Jetronic fuel injection with "200" headM20B201,991 cc (121.5 cu in)92 kW (125 PS; 123 bhp) at 5,800 rpm174 N⋅m (128 lb⋅ft) at 4,000 rpm80 mm (3.15 in)66 mm (2.60 in)9.0:1 (catalyst) 9.8:1 (non-catalyst)1984-1987LE-Jetronic fuel injection with "731" headM20B201,991 cc (121.5 cu in)95 kW (129 PS; 127 bhp) at 6,000 rpm164 N⋅m (121 lb⋅ft) at 4,300 rpm80 mm (3.15 in)66 mm (2.60 in)8.8:11986-1992Motronic 1.1/1.3 engine management Compression ratio reduced to accommodate emissions controls and unleaded gasolineM20B232,316 cc (141.3 cu in)105 kW (143 PS; 141 bhp) at 5,300 rpm190 N⋅m (140 lb⋅ft) at 4,500 rpm80 mm (3.15 in)76.8 mm (3.02 in)9.5:11977-1982K-Jetronic fuel injectionM20B232,316 cc (141.3 cu in)102 kW (139 PS; 137 bhp) at 5,300 rpm205 N⋅m (151 lb⋅ft) at 4,000 rpm80 mm (3.15 in)76.8 mm (3.02 in)9.0:1 (catalyst) 9.8:1 (non-catalyst)1982-1983L-JetronicM20B232,316 cc (141.3 cu in)110 kW (150 PS; 148 bhp) at 6,000 rpm205 N⋅m (151 lb⋅ft) at 4,000 rpm80 mm (3.15 in)76.8 mm (3.02 in)9.0:1 (catalyst) 9.8:1 (non-catalyst)1983-1987LE-JetronicM20B252,494 cc (152.2 cu in)126 kW (171 PS; 169 bhp) at 5,800 rpm226 N⋅m (167 lb⋅ft) at 4,000 rpm84 mm (3.31 in)75 mm (2.95 in)9.4:11985-1990For markets that did not require a catalytic converterM20B252,494 cc (152.2 cu in)125 kW (170 PS; 168 hp) at 5,800 rpm226 N⋅m (167 lb⋅ft) at 4,300 rpm84 mm (3.31 in)75 mm (2.95 in)8.8:11987-1993For markets that required a catalytic converterM20B272,693 cc (164.3 cu in)90 kW (122 PS; 121 hp) at 4,250 rpm230 N⋅m (170 lb⋅ft) at 3,250 rpm84 mm (3.31 in)81 mm (3.19 in)9.0:11982-1987For markets that required a catalytic converterM20B272,693 cc (164.3 cu in)92 kW (125 PS; 123 hp) at 4,250 rpm240 N⋅m (177 lb⋅ft) at 3,250 rpm84 mm (3.31 in)81 mm (3.19 in)11.0:11982-1985For markets that did not require a catalytic converter Early high compression variantM20B272,693 cc (164.3 cu in)95 kW (129 PS; 127 hp) at 4,250 rpm240 N⋅m (177 lb⋅ft) at 3,250 rpm84 mm (3.31 in)81 mm (3.19 in)10.2:11985-1987For markets that did not require a catalytic converter Compression ratio reduced to mitigate knockingM20B272,693 cc (164.3 cu in)95 kW (129 PS; 127 hp) at 4,800 rpm240 N⋅m (177 lb⋅ft) at 3,200 rpm84 mm (3.31 in)81 mm (3.19 in)8.5:11988"Super" Eta engine Motronic 1.1
Recorded vehicle applications
M20B20
1977–1981 E12 5 Series 520/6 (carburettor)1977–1982 E21 3 Series 320/6 (carburettor)
M20B20KE
1981–1982 E28 5 Series 520i (K-Jetronic)
M20B20LE
1982–1984 E28 5 Series 520i ( L-Jetronic )1982–1984 E30 3 Series 320i (L-Jetronic)1984–1987 E28 5 Series 520i (LE-Jetronic)1984–1987 E30 3 Series 320i (LE-Jetronic)
M20B20 (Motronic)
1986–1987 E28 3 Series 520i (Motronic)1987–1992 E30 3 Series 320i (Motronic)1988–1990 E34 5 Series 520i (Motronic)1989–1992 Bertone Freeclimber (Freeclimber I)
M20B23
1977–1982 E21 3 Series 323i (K-Jetronic)1982–1984 E30 3 Series 323i (L-Jetronic)1984–1987 E30 3 Series 323i (LE-Jetronic)
M20B25
1985–1993 E30 3 Series 325i1989–1990 E34 5 Series 525i1988–1991 Z1
M20B27
1982–1987 E30 3 Series 325e, 325e1982–1988 E28 5 Series 525e (called 528e in North America)1989–1992 E30 3 Series 325iS (only available in South Africa)1989–1992 Bertone Freeclimber (Freeclimber I)
BMW automotive engine directory
Design, development and variant notes
The 'little six' M20 has an iron block, aluminium cross-flow head and a belt-driven single overhead camshaft. Its smaller bore spacing and different mounting angle distinguish it from the larger M30.
Early 2.0-litre and 2.3-litre versions used different fuelling systems, including carburettor and Bosch K-Jetronic arrangements. The M21 diesel was developed from the M20 architecture.
Variant dimensions and compression
These values are associated with the named variant and source qualifier; equipment and market specifications can differ. A dash means the value is not listed here.
VariantBore (mm)Stroke (mm)Compression ratioSource qualifierM20B20VE80669.2:1Early carburetted versionM20B23KE8076.89.5:1Initial K-Jetronic versionM20B2584759.4:1Initial 1985 version
Data adapted from the cited Wikipedia revision by Wikipedia contributors under CC BY-SA 4.0. Production dates and fitments reflect that revision; verify the exact engine code, market and vehicle before applying a specification.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.
Wikipedia: List of BMW engines. Wikipedia contributors; CC BY-SA 4.0. Source revision oldid 1382309748; accessed 2026-11-10.Wikipedia: BMW M20. Wikipedia contributors; CC BY-SA 4.0. Source revision oldid 1384599794; accessed 2026-11-10.
Further Wikipedia-sourced detailsThe following additional information is drawn from the cited Wikipedia revision by Wikipedia contributors, available under CC BY-SA 4.0. An open-ended date reflects the source snapshot, not confirmed current production or fitment.Additional technical and variant notesM20B27 is the low-speed, efficiency-oriented eta derivative: 2,693 cc with an 84 × 81 mm bore and stroke. The article lists different compression and management specifications by market and model year, including a 1988 US 'Super Eta' update.A South African E30 325iS racing-related development is listed at 145 kW initially and 155 kW for the later HP2/Evo2 version; these should not be confused with the standard 325e eta calibration.Further specifications from the cited articleAdditional facts are adapted from this Wikipedia revision by Wikipedia contributors, under CC BY-SA 4.0.Compared with the M30, the M20 uses a timing belt, 91 mm rather than 100 mm bore spacing, and a 20-degree rather than 30-degree mounting slant.The M20B20VE carburettor version and the M20B23KE are listed with 6,400 rpm redlines; the 1982 M20B20LE is listed at 6,200 rpm. The updated M20B23LE from September 1983 and the M20B25 are listed at 6,500 rpm.The 1988 US Super Eta update used Motronic 1.1, the 885 cylinder head and 8.5:1 compression; its redline rose to 5,200 rpm, with 95 kW at 4,800 rpm.Open each version to inspect formatting, tables and photographs.
Revision 5: BMW M20 engines
BMW automotive engine families listed as M20. Specifications below retain the source's separate family and variant labels.
Family specifications
BMW M20 engine
| Field | Reported value |
|---|
| Production | 1977–1993 |
| Configuration | Straight-6 |
| Displacement | 2.0 L (1,991 cc) 2.3 L (2,316 cc) 2.5 L (2,494 cc) 2.7 L (2,693 cc) |
| Cylinder bore | 80 mm (3.15 in) 84 mm (3.31 in) |
| Piston stroke | 66 mm (2.60 in) 75 mm (2.95 in) 76.8 mm (3.02 in) 81 mm (3.19 in) |
| Cylinder block material | Cast iron |
| Cylinder head material | Cast aluminum alloy |
| Valvetrain | SOHC |
| Fuel type | Petrol |
| Predecessor | None |
| Successor | BMW M50 |
Variant specifications
Models
| Version | Displacement | Power | Torque | Bore | Stroke | Compression Ratio | Years | Notes |
|---|
| M20B20 | 1,991 cc (121.5 cu in) | 90 kW (122 PS; 121 hp) at 6,000 rpm | 163 N⋅m (120 lb⋅ft) at 4,000 rpm | 80 mm (3.15 in) | 66 mm (2.60 in) | 9.2:1 | 1977-1982 | Solex 4A1 variant |
| M20B20 | 1,991 cc (121.5 cu in) | 92 kW (125 PS; 123 bhp) at 5,800 rpm | 170 N⋅m (125 lb⋅ft) at 4,000 rpm | 80 mm (3.15 in) | 66 mm (2.60 in) | 9.0:1 (catalyst) 9.8:1 (non-catalyst) | 1982-1984 | L-Jetronic fuel injection with "200" head |
| M20B20 | 1,991 cc (121.5 cu in) | 92 kW (125 PS; 123 bhp) at 5,800 rpm | 174 N⋅m (128 lb⋅ft) at 4,000 rpm | 80 mm (3.15 in) | 66 mm (2.60 in) | 9.0:1 (catalyst) 9.8:1 (non-catalyst) | 1984-1987 | LE-Jetronic fuel injection with "731" head |
| M20B20 | 1,991 cc (121.5 cu in) | 95 kW (129 PS; 127 bhp) at 6,000 rpm | 164 N⋅m (121 lb⋅ft) at 4,300 rpm | 80 mm (3.15 in) | 66 mm (2.60 in) | 8.8:1 | 1986-1992 | Motronic 1.1/1.3 engine management Compression ratio reduced to accommodate emissions controls and unleaded gasoline |
| M20B23 | 2,316 cc (141.3 cu in) | 105 kW (143 PS; 141 bhp) at 5,300 rpm | 190 N⋅m (140 lb⋅ft) at 4,500 rpm | 80 mm (3.15 in) | 76.8 mm (3.02 in) | 9.5:1 | 1977-1982 | K-Jetronic fuel injection |
| M20B23 | 2,316 cc (141.3 cu in) | 102 kW (139 PS; 137 bhp) at 5,300 rpm | 205 N⋅m (151 lb⋅ft) at 4,000 rpm | 80 mm (3.15 in) | 76.8 mm (3.02 in) | 9.0:1 (catalyst) 9.8:1 (non-catalyst) | 1982-1983 | L-Jetronic |
| M20B23 | 2,316 cc (141.3 cu in) | 110 kW (150 PS; 148 bhp) at 6,000 rpm | 205 N⋅m (151 lb⋅ft) at 4,000 rpm | 80 mm (3.15 in) | 76.8 mm (3.02 in) | 9.0:1 (catalyst) 9.8:1 (non-catalyst) | 1983-1987 | LE-Jetronic |
| M20B25 | 2,494 cc (152.2 cu in) | 126 kW (171 PS; 169 bhp) at 5,800 rpm | 226 N⋅m (167 lb⋅ft) at 4,000 rpm | 84 mm (3.31 in) | 75 mm (2.95 in) | 9.4:1 | 1985-1990 | For markets that did not require a catalytic converter |
| M20B25 | 2,494 cc (152.2 cu in) | 125 kW (170 PS; 168 hp) at 5,800 rpm | 226 N⋅m (167 lb⋅ft) at 4,300 rpm | 84 mm (3.31 in) | 75 mm (2.95 in) | 8.8:1 | 1987-1993 | For markets that required a catalytic converter |
| M20B27 | 2,693 cc (164.3 cu in) | 90 kW (122 PS; 121 hp) at 4,250 rpm | 230 N⋅m (170 lb⋅ft) at 3,250 rpm | 84 mm (3.31 in) | 81 mm (3.19 in) | 9.0:1 | 1982-1987 | For markets that required a catalytic converter |
| M20B27 | 2,693 cc (164.3 cu in) | 92 kW (125 PS; 123 hp) at 4,250 rpm | 240 N⋅m (177 lb⋅ft) at 3,250 rpm | 84 mm (3.31 in) | 81 mm (3.19 in) | 11.0:1 | 1982-1985 | For markets that did not require a catalytic converter Early high compression variant |
| M20B27 | 2,693 cc (164.3 cu in) | 95 kW (129 PS; 127 hp) at 4,250 rpm | 240 N⋅m (177 lb⋅ft) at 3,250 rpm | 84 mm (3.31 in) | 81 mm (3.19 in) | 10.2:1 | 1985-1987 | For markets that did not require a catalytic converter Compression ratio reduced to mitigate knocking |
| M20B27 | 2,693 cc (164.3 cu in) | 95 kW (129 PS; 127 hp) at 4,800 rpm | 240 N⋅m (177 lb⋅ft) at 3,200 rpm | 84 mm (3.31 in) | 81 mm (3.19 in) | 8.5:1 | 1988 | "Super" Eta engine Motronic 1.1 |
Recorded vehicle applications
M20B20
- 1977–1981 E12 5 Series 520/6 (carburettor)
- 1977–1982 E21 3 Series 320/6 (carburettor)
M20B20KE
- 1981–1982 E28 5 Series 520i (K-Jetronic)
M20B20LE
- 1982–1984 E28 5 Series 520i ( L-Jetronic )
- 1982–1984 E30 3 Series 320i (L-Jetronic)
- 1984–1987 E28 5 Series 520i (LE-Jetronic)
- 1984–1987 E30 3 Series 320i (LE-Jetronic)
M20B20 (Motronic)
- 1986–1987 E28 3 Series 520i (Motronic)
- 1987–1992 E30 3 Series 320i (Motronic)
- 1988–1990 E34 5 Series 520i (Motronic)
- 1989–1992 Bertone Freeclimber (Freeclimber I)
M20B23
- 1977–1982 E21 3 Series 323i (K-Jetronic)
- 1982–1984 E30 3 Series 323i (L-Jetronic)
- 1984–1987 E30 3 Series 323i (LE-Jetronic)
M20B25
- 1985–1993 E30 3 Series 325i
- 1989–1990 E34 5 Series 525i
- 1988–1991 Z1
M20B27
- 1982–1987 E30 3 Series 325e, 325e
- 1982–1988 E28 5 Series 525e (called 528e in North America)
- 1989–1992 E30 3 Series 325iS (only available in South Africa)
- 1989–1992 Bertone Freeclimber (Freeclimber I)
BMW automotive engine directory
Design, development and variant notes
The 'little six' M20 has an iron block, aluminium cross-flow head and a belt-driven single overhead camshaft. Its smaller bore spacing and different mounting angle distinguish it from the larger M30.
Early 2.0-litre and 2.3-litre versions used different fuelling systems, including carburettor and Bosch K-Jetronic arrangements. The M21 diesel was developed from the M20 architecture.
Variant dimensions and compression
These values are associated with the named variant and source qualifier; equipment and market specifications can differ. A dash means the value is not listed here.
| Variant | Bore (mm) | Stroke (mm) | Compression ratio | Source qualifier |
|---|
| M20B20VE | 80 | 66 | 9.2:1 | Early carburetted version |
| M20B23KE | 80 | 76.8 | 9.5:1 | Initial K-Jetronic version |
| M20B25 | 84 | 75 | 9.4:1 | Initial 1985 version |
Data adapted from the cited Wikipedia revision by Wikipedia contributors under CC BY-SA 4.0. Production dates and fitments reflect that revision; verify the exact engine code, market and vehicle before applying a specification.
Sources
Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.
Further Wikipedia-sourced details
The following additional information is drawn from the cited Wikipedia revision by Wikipedia contributors, available under CC BY-SA 4.0. An open-ended date reflects the source snapshot, not confirmed current production or fitment.
Additional technical and variant notes
M20B27 is the low-speed, efficiency-oriented eta derivative: 2,693 cc with an 84 × 81 mm bore and stroke. The article lists different compression and management specifications by market and model year, including a 1988 US 'Super Eta' update.
A South African E30 325iS racing-related development is listed at 145 kW initially and 155 kW for the later HP2/Evo2 version; these should not be confused with the standard 325e eta calibration.
Further specifications from the cited article
Additional facts are adapted from this Wikipedia revision by Wikipedia contributors, under CC BY-SA 4.0.
Compared with the M30, the M20 uses a timing belt, 91 mm rather than 100 mm bore spacing, and a 20-degree rather than 30-degree mounting slant.
The M20B20VE carburettor version and the M20B23KE are listed with 6,400 rpm redlines; the 1982 M20B20LE is listed at 6,200 rpm. The updated M20B23LE from September 1983 and the M20B25 are listed at 6,500 rpm.
The 1988 US Super Eta update used Motronic 1.1, the 885 cylinder head and 8.5:1 compression; its redline rose to 5,200 rpm, with 95 kW at 4,800 rpm.