The Porsche M 44.09 is a 2,480 cc, water‑cooled inline‑four naturally aspirated petrol engine produced between 1996 and 2000. It features Bosch Motronic M2.1 digital fuel injection, dual overhead camshafts (DOHC), and a compression ratio of 10.0:1. In standard form it delivered 103 kW (140 PS) and 225 Nm of torque, emphasizing linear power delivery and high‑rpm responsiveness.
Fitted exclusively to the Porsche Boxster (986) for European and select global markets, the…
All production years (1996–2000) meet Euro 2 standards (German KBA Type Approval #KBA/M44.09/97).
The Porsche M 44.09 is a 2,480 cc water‑cooled inline‑four naturally aspirated petrol engine engineered for the entry-level Boxster (1996–2000). It combines DOHC architecture with Bosch Motronic digital injection to deliver responsive throttle behavior and smooth high-rpm operation. Designed to meet Euro 2 emissions standards, it integrates catalytic converters and precise fuel control for regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,480 cc | |
Fuel type | Petrol (RON 95 min) | |
Configuration | Inline‑4, DOHC, 16‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 95.0 mm × 87.5 mm | |
Power output | 103 kW (140 PS) @ 5,500 rpm | |
Torque | 225 Nm @ 4,200 rpm | |
Fuel system | Bosch Motronic M2.1 digital electronic injection | |
Emissions standard | Euro 2 | |
Compression ratio | 10.0:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 125 kg |
The Porsche M 44.09 was used exclusively in Porsche's 986 Boxster platform with mid‑mounted, longitudinal inline‑four layout. This engine powered the base Boxster 2.5 from 1996 through 2000, featuring a unique water‑cooled four-cylinder in Porsche’s otherwise six-cylinder lineup. No licensed third-party applications exist. All adaptations are documented in OEM technical bulletins.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from Porsche technical bulletins (1996–2000) and German KBA failure statistics (1998–2005). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M 44.09 is generally robust but has a known weakness in early IMS bearings (1996–1997). Post-1998 engines feature a sealed IMS bearing and improved durability. Strict adherence to oil change intervals (every 10,000 km) and use of correct oil greatly enhance long-term reliability.
Top issues include IMS bearing wear (early models), timing chain tensioner degradation, Motronic sensor faults, and valve cover oil leaks. These are documented in Porsche Technical Bulletin 986/96/08 and service records from the late 1990s.
Exclusively the Porsche Boxster (986) 2.5 from 1996 to 2000. It was the only inline-four engine ever used in a production Porsche and was replaced by a 2.7L flat-six in 2000. No other models or manufacturers used this engine.
Modest gains are possible via exhaust, intake, and ECU remap—typically +10–15 PS. However, the engine’s modest output and unique architecture limit tuning potential compared to six-cylinder variants. Aggressive tuning is not common and may accelerate IMS or bearing wear.
Efficient for its era: ~10–12 L/100km (city) and ~7–8 L/100km (highway), or roughly 28–33 mpg UK combined. Real-world figures typically land around 30 mpg (UK) with mixed driving. RON 95 fuel is sufficient, though RON 98 improves refinement.
Yes. The M 44.09 uses an interference valvetrain design. Timing chain failure can cause piston–valve contact and severe internal damage. However, the chain is robust if maintained and inspected during major services.
Porsche specifies a 10W-40 semi-synthetic or mineral oil meeting specification L-710. Full synthetic is acceptable if compatible with older seals. Change every 10,000 km to protect the IMS bearing and timing components.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
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