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 M 44.09 was engineered as an entry‑level engine to broaden the model’s appeal while maintaining Porsche’s driving dynamics. Emissions compliance was achieved through closed‑loop fuel control, secondary air injection, and catalytic converters, meeting Euro 2 standards across all markets.
One documented concern is intermediate shaft (IMS) bearing wear in early production units, highlighted in Porsche Technical Bulletin 986/96/08. This issue stems from inadequate lubrication of the IMS bearing under sustained high‑rpm operation, particularly when oil changes are extended. In 1998, Porsche revised the IMS bearing design to a larger, more robust sealed unit to improve service life.
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 | Porsche Classic 10W-40 or equivalent semi-synthetic | |
| Dry weight | 125 kg |
The M 44.09 delivers balanced performance for an entry-level Porsche but requires strict adherence to 10,000 km oil change intervals to protect the IMS bearing and timing chain. RON 95 fuel is acceptable, though RON 98 improves high-rpm smoothness. Early engines (1996–1997) use a smaller dual-row IMS bearing prone to wear under extended oil intervals or high-rpm use; post-1998 units feature a larger sealed bearing. Oil quality and regular changes are critical to prevent IMS-related failure, which can lead to timing disruption and catastrophic engine damage.
Oil Specs: Requires semi-synthetic or mineral 10W-40 oil meeting Porsche L-710 (Porsche Lubricants Specification L-710). Full synthetic not required but acceptable if compatible.
Emissions: Euro 2 certification applies to all production years (KBA Type Approval #KBA/M44.09/97). No market-specific deviations.
Power Ratings: Measured per DIN 70020 standards. Output consistent across all Boxster 2.5 models (Porsche PT‑1998).
Porsche Technical Information System (TIS): Docs P986-M44, P986-FI-96, 986/96/08
Kraftfahrt-Bundesamt (KBA) Type Approval Database (KBA/M44.09/97)
Porsche ETK (Electronic Parts Catalogue) – 986 Chassis Section
DIN 70020 Engine Power Certification Standard
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.
The engine code M 44.09 is stamped on the rear face of the crankcase near the flywheel (Porsche TIS P986-ID-01). The 10th digit of the VIN indicates model year, while model designation 'Boxster 2.5' confirms application. Critical differentiation: M 44.09 uses an inline‑4 layout with dual cam covers and a single exhaust manifold—visually distinct from the flat‑six M96 engines. The presence of a 140 PS output rating and Motronic M2.1 ECU confirms this variant.
The M 44.09's primary reliability risk is intermediate shaft (IMS) bearing wear in early-production units, with elevated incidence in high-mileage or poorly maintained examples. Porsche internal service data from 1999 noted IMS-related failures before 100,000 km in pre-1998 builds, while German KBA records show elevated mechanical failure notices in early Boxster 2.5 models. Extended oil change intervals and sustained high-RPM operation increase stress, making oil quality and maintenance critical.
Analysis derived from Porsche technical bulletins (1996–2000) and German KBA failure statistics (1998–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-44-09.
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