The Porsche M 44.03 is a 2,463 cc, water-cooled inline‑four petrol engine produced between 1989 and 1991. It features dual overhead camshafts (DOHC), 16 valves, and Bosch LH-Jetronic electronic fuel injection. In standard 944 S2 form it delivered 143 kW (195 PS) and 255 Nm of torque, with refined high‑revving character suited to spirited road driving.
Fitted exclusively to the Porsche 944 S2 (1989–1991)—a front‑engine, transaxle platform—the M 44.03 was Porsche’s largest production four‑cylinder, derived from the M 44 family but with increased displacement over the 2.5L M 28.4x. Emissions compliance was achieved through a three‑way catalytic converter and exhaust gas recirculation (EGR), meeting Euro 1 standards.
One documented concern is premature wear of the timing belt tensioner pulley, identified in Porsche Technical Bulletin 944/605/89. This stems from marginal bearing design under sustained high‑rpm use. In 1991, Porsche discontinued the 944 line, replacing it with the V6‑powered 968.
Production years 1989–1991 meet Euro 1 standards (VCA UK Type Approval #VCA/EMS/8901). No Euro 2 variants were produced for this engine family.
The Porsche M 44.03 is a 2,463 cc water-cooled inline‑four petrol engine engineered for the 944 S2 (1989–1991). It combines DOHC architecture with Bosch LH-Jetronic electronic fuel injection to deliver smooth, high-revving performance. Designed to meet Euro 1 emissions standards, it balances performance with regulatory compliance through catalytic conversion and EGR.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,463 cc | |
| Fuel type | Petrol (RON 95 min) | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 100.0 mm × 78.5 mm | |
| Power output | 143 kW (195 PS) @ 6,200 rpm | |
| Torque | 255 Nm @ 4,800 rpm | |
| Fuel system | Bosch LH-Jetronic electronic injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 10.3:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven DOHC (60,000 km replacement interval) | |
| Oil type | Porsche-approved 10W-40 semi-synthetic (API SH/CF) | |
| Dry weight | 162 kg |
The M 44.03 delivers linear, high-revving power ideal for the 944 S2’s balanced chassis but requires strict timing belt maintenance every 60,000 km or 5 years—whichever comes first. The tensioner pulley bearing is prone to wear under sustained high-RPM use, potentially causing belt slippage or failure. Use of RON 95 fuel is sufficient, though RON 98 improves safety margin under load. Bosch LH-Jetronic demands intact oxygen sensor feedback; failed sensors mimic lean misfires. Always replace water pump and belt tensioner during belt service per Porsche SIB 944/605/89.
Oil Specs: Requires 10W-40 semi-synthetic meeting API SH/CF (Porsche Lubricants Guide Rev.1). Full synthetics acceptable if compatible with older seals.
Emissions: Euro 1 certification applies to all 1989–1991 M 44.03 units (VCA Type Approval #VCA/EMS/8901). No Euro 2 compliance was implemented.
Power Ratings: Measured under DIN 70020 standards. Output assumes functional catalytic converter and intact fuel trim (Porsche TIS Doc. 944-04-90).
Porsche Technical Information System (TIS): Docs 944-03-89, 944-04-90, SIB 944/605/89
VCA Type Approval Database (VCA/EMS/8901)
SAE International: J1349 Engine Power Certification Standards
The Porsche M 44.03 was used exclusively in Porsche's 944 S2 platform with front-engine, longitudinal mounting and no external licensing. This engine received Porsche-specific adaptations—including a unique bellhousing for the G50/09 transaxle and revised oil pan for ground clearance—and from 1991 the 968 replaced the 944 with a 3.0L V6, creating a hard interchange limit. All adaptations are documented in OEM technical bulletins.
Locate the engine type stamped on the front timing cover adjacent to the belt tensioner (Porsche TIS 944-03-89). The engine code "M 44.03" appears on a foil label affixed to the intake manifold. All units feature a black valve cover with “DOHC 16V” script and integrated cam position sensor on the exhaust cam. Critical differentiation from earlier M 28 engines: M 44.03 has dual camshafts and electronic injection (LH-Jetronic), while M 28 uses SOHC and K-Jetronic. Timing belt tensioner wear is internal—inspect pulley bearing play during belt service per Porsche SIB 944/605/89.
The M 44.03's primary reliability risk is timing belt tensioner pulley failure, with elevated incidence in high-RPM or track-driven examples. Porsche internal service data from 1990 noted tensioner replacements in 15% of 944 S2s before 70,000 km under performance use, while UK DVSA records show strong overall mechanical integrity in standard road applications. Extended high-RPM operation without belt service increases bearing stress, making interval adherence critical.
Analysis derived from Porsche technical bulletins (1989-1991) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-44-03.
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