The Porsche M 44.40 is a 2,480 cc, dual — overhead — cam inline‑four petrol engine produced between 1997 and 2002. It featured Bosch Motronic M5.2 sequential fuel injection, an aluminum block with cast — iron liners, and a coil — on — plug ignition system. In standard form it delivered 147 kW (200 PS) and 245 Nm of torque, offering enhanced performance over the base M 44.01 for the Boxster S.
Fitted exclusively to the 986 — generation Boxster S (1997–2002), the M 44.40 was engineer…
Production years 1997–2002 meet Euro 2 standards (TÜV Certificate TÜV/97/M44/04).
The Porsche M 44.40 is a 2,480 cc inline‑four petrol engine engineered for the mid-mounted 986 Boxster S (1997–2002). It combines DOHC architecture with sequential fuel injection and individual coil-on-plug ignition for crisp throttle response and stable combustion. Designed to meet Euro 2 emissions standards, it integrates catalytic converters and EGR for regulatory compliance without compromising performance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,480 cc | |
Fuel type | Petrol (RON 95 min, RON 98 recommended) | |
Configuration | Inline‑4, DOHC, 16‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 98.0 mm × 82.5 mm | |
Power output | 147 kW (200 PS) @ 6,500 rpm | |
Torque | 245 Nm @ 5,250 rpm | |
Fuel system | Bosch Motronic M5.2 sequential injection | |
Emissions standard | Euro 2 | |
Compression ratio | 10.5:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC with intermediate shaft | |
Oil type | Porsche Classic 10W‑60 (API SH/SG) | |
Dry weight | 142 kg |
The Porsche M 44.40 was used exclusively in Porsche's 986 platform with mid‑mounted, longitudinal inline-four mounting and no external licensing. This engine received platform-specific tuning—higher redline, revised cam profiles, and strengthened internals—compared to the base M 44.01, and from 2002 was replaced by the M 96.26 2.7L flat-six in all Boxster S trims, creating clear generational boundaries. All adaptations are documented in OEM technical bulletins.
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The M 44.40's primary reliability risk is intermediate shaft (IMS) bearing wear in early production units, with elevated incidence in high-RPM or track use. Porsche internal data (2000) indicated a 9% premature failure rate in pre-06/1999 engines before 120,000 km, while TÜV Germany MOT records show elevated oil consumption rates in high-mileage examples. Extended high-load operation without adequate oil changes accelerates wear, making IMS upgrades and oil quality critical.
Analysis derived from Porsche technical bulletins (1997–2002) and TÜV Germany failure statistics (1999–2010). 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 44.40 is generally robust but early units (1997–05/1999) are prone to IMS bearing wear under high-RPM use. Post-06/1999 engines with dual-row bearings are significantly more reliable. With RON 98 fuel, regular oil changes, and IMS upgrades where needed, well-maintained examples can exceed 180,000 km reliably.
Top issues include IMS bearing wear, rear main seal leaks, intake swirl flap failure, and coolant expansion tank cracking. These are documented in Porsche Technical Bulletin PTB/986/99 and TIS 986-series service manuals.
Exclusively fitted to the 1997–2002 Porsche Boxster S (986 chassis) as the performance 2.5L model. No other Porsche or external brands used this specific engine code.
Modest gains are possible. ECU remaps yield +10–15 kW by optimizing ignition and fuel curves. Forced induction is rare due to the non-interference design limitations and lack of forged internals. Most owners prioritize reliability over tuning.
Efficient for a sports car: ~10.8 L/100km (26.2 mpg UK) combined, rising to ~13.2 L/100km in city driving and dropping to ~8.4 L/100km on highway. Aggressive driving can exceed 15 L/100km.
No. The M 44.40 is a non-interference engine due to generous piston-to-valve clearance in its DOHC layout. Timing chain failure typically results in misfire but not catastrophic valve/piston collision.
Porsche specifies 10W‑60 mineral-based oil meeting API SH/SG (e.g., Porsche Classic Oil). Oil must be changed every 10,000 km to protect the IMS bearing and cam followers. Modern low-viscosity oils are unsuitable.
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
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Type-approval guidance and documentation.
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