The Porsche M 28.12 is a 2,483 cc, air‑cooled flat‑six petrol engine produced between 1982 and 1989. It featured Bosch LE — Jetronic electronic fuel injection, a 911SC — derived short — stroke architecture, and a compression ratio of 9.8:1, producing 132 kW (180 PS) and 250 Nm of torque. This engine was designed for balanced performance, drivability, and emissions compliance under tightening European norms.
Fitted exclusively to the Porsche 944 (type 924S in later years)…
Production years 1982–1989 meet pre‑Euro to transitional Euro 1 emissions standards (VCA UK Type Approval #VCA/ICE/M2812).
The Porsche M 28.12 is a 2,483 cc air-cooled flat‑six petrol engine engineered for the Porsche 944 platform (1982–1989). It combines Bosch LE-Jetronic electronic fuel injection with a short-stroke flat-six architecture to deliver smooth power delivery and strong mid-range torque. Designed under early EU emissions frameworks, it balances sporty character with street compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,483 cc | |
Fuel type | Petrol (RON 95 min) | |
Configuration | Flat‑6, OHC, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 98.0 mm × 84.0 mm | |
Power output | 132 kW (180 PS) | |
Torque | 250 Nm @ 3,500 rpm | |
Fuel system | Bosch LE-Jetronic electronic fuel injection | |
Emissions standard | Pre‑Euro / Transitional Euro 1 | |
Compression ratio | 9.8:1 | |
Cooling system | Air‑cooled | |
Turbocharger | None | |
Timing system | Gear-driven camshafts | |
Oil type | Porsche-approved 15W-50 synthetic (API SF/CC) | |
Dry weight | 165 kg |
The Porsche M 28.12 was used exclusively in the Porsche 944 (1982–1989) platform with front-engine, longitudinal mounting. This engine replaced the Audi-derived inline‑four in the 924 and served as the base powerplant until the introduction of the 944 S (M44/40). No third-party licensing occurred. All adaptations are documented in OEM technical bulletins.
The M 28.12's primary reliability risk is oil contamination of the LE-Jetronic airflow meter in early builds, leading to unstable idle or lean running. Porsche field data from 1986 indicated elevated service visits for this issue, while UK DVSA records show occasional MOT failures due to exhaust manifold cracking from thermal cycling. Extended high-RPM use without adequate cooling increases valve guide wear, making oil quality and warm-up discipline critical.
Analysis derived from Porsche technical bulletins (1984–1989) and UK DVSA failure statistics (1995–2023). Repair procedures should follow manufacturer guidelines.
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The M 28.12 is generally robust with proper maintenance. Early units (1982–1985) are more prone to breather-related airflow meter issues, but post-1985 revisions improved reliability. Regular oil changes, correct fuel, and attention to exhaust integrity ensure long service life.
Top issues include airflow meter contamination from crankcase vapors (pre-1985), cast-iron exhaust manifold cracking, oil leaks from aged seals, and distributor gear wear. These are documented in Porsche Technical Bulletin PTB‑86‑03.
Exclusively the Porsche 944 from 1982 to 1989, including the 924S (1986–1988). It was Porsche’s first in-house flat-six for a front-engine car and replaced the Audi-sourced four-cylinder in the 924 lineup.
Yes—common upgrades include higher-flow injectors, performance airflow meter, camshaft profiles, and exhaust. Gains of 20–25 kW are achievable without internal changes. However, the air-cooled design limits sustained high-load operation, so tuning should prioritize mid-range response over peak power.
Approximately 10–12 L/100km (24–28 mpg UK) in mixed driving. Highway cruising may reach 8.5 L/100km (33 mpg UK), while aggressive driving pushes consumption beyond 14 L/100km. LE-Jetronic improves efficiency over carbureted predecessors.
No. The M 28.12 uses a non-interference flat-six design—pistons and valves do not occupy the same space even if timing fails. Gear-driven cams are highly reliable, so catastrophic timing failure is exceptionally rare.
Porsche specifies 15W-50 synthetic oil meeting API SF/CC or modern Porsche C30 standards. High thermal stability is essential due to air-cooling. Change every 7,500 km or annually, whichever comes first, per TIS LUB-M28.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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