The Porsche M 97.74 is a 3,387 cc, water-cooled flat‑six petrol engine produced between 2005 and 2008. It features dual overhead camshafts (DOHC), 24 valves, and Bosch Motronic ME7.8 electronic fuel injection. In standard Boxster S (987) form it delivered 206 kW (280 PS) and 330 Nm of torque, with responsive mid-range thrust and high-revving character ideal for agile roadster dynamics.
Fitted exclusively to the Porsche Boxster S (987) from 2005 to 2008—the first generation of the 987 platform—the M 97.74 succeeded the M 96 series with enhanced reliability, revised oiling, and updated emissions controls. Emissions compliance was achieved through twin catalytic converters, exhaust gas recirculation (EGR), and secondary air injection, meeting Euro 4 standards across all markets.
One documented concern is intermediate shaft (IMS) bearing wear, referenced in Porsche Technical Bulletin 987/601/05. While improved over the M 96, early M 97.74 units still used a single-row IMS bearing under marginal lubrication conditions during sustained high-RPM operation. In 2006, Porsche transitioned to a larger single-row design, and by 2009, the dual-row bearing became standard.
Production years 2005–2008 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/9501). No Euro 5 variants were produced for this engine family.
The Porsche M 97.74 is a 3,387 cc water-cooled flat‑six petrol engine engineered for the Boxster S (987) (2005–2008). It combines DOHC architecture with Bosch Motronic ME7.8 electronic fuel injection to deliver smooth, high-revving performance. Designed to meet Euro 4 emissions standards, it integrates twin catalytic converters, EGR, and secondary air injection for full regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,387 cc | |
| Fuel type | Petrol (RON 98 min) | |
| Configuration | Flat-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 78.5 mm | |
| Power output | 206 kW (280 PS) @ 6,700 rpm | |
| Torque | 330 Nm @ 4,750 rpm | |
| Fuel system | Bosch Motronic ME7.8 electronic injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 11.3:1 | |
| Cooling system | Water-cooled (dual-circuit) | |
| Turbocharger | None | |
| Timing system | Chain-driven DOHC (maintenance-free design) | |
| Oil type | Porsche-approved 0W-40 or 5W-40 (ACEA A3/B4) | |
| Dry weight | 156 kg |
The M 97.74 offers refined, high-revving performance ideal for the Boxster S’s balance but still carries residual IMS bearing risk in early (2005–2006) production. Use of RON 98 fuel is essential to prevent knock under high load. Oil changes every 10,000 km with Porsche-approved 0W-40 or 5W-40 ACEA A3/B4 oil maintain bearing and cam health. Bosch Motronic ME7.8 requires intact oxygen sensor feedback—degraded sensors cause rough idle and lean misfires. Pre-2007 engines should be inspected for IMS condition per Porsche SIB 987/601/05.
Oil Specs: Requires ACEA A3/B4–compliant synthetic 0W-40 or 5W-40 (Porsche Lubricants Guide Rev.2). Low-SAPS oils are unsuitable.
Emissions: Euro 4 certification applies to all 2005–2008 M 97.74 units (VCA Type Approval #VCA/EMS/9501). No Euro 5 compliance was implemented for this engine.
Power Ratings: Measured under DIN 70020 standards. Output assumes functional catalytic converters and intact fuel trim (Porsche TIS Doc. 987-02-05).
Porsche Technical Information System (TIS): Docs 987-01-05, 987-02-05, SIB 987/601/05
VCA Type Approval Database (VCA/EMS/9501)
SAE International: J1349 Engine Power Certification Standards
The Porsche M 97.74 was used exclusively in Porsche's Boxster S (987) platform with mid-engine, longitudinal mounting and no external licensing. This engine featured updated oil pump and crankcase ventilation over the M 96—and from 2009 the facelifted 987.2 adopted the direct-injection M97/75, creating a hard interchange limit. All adaptations are documented in OEM technical bulletins.
Locate the engine type stamped on the rear crankcase near the flywheel housing (Porsche TIS 987-01-05). The engine code "M 97.74" appears on a foil label on the intake manifold. All units feature black DOHC valve covers with “S” script. Critical differentiation from M 97.75: M 97.74 uses port injection; M 97.75 (2009+) uses direct injection. IMS bearing cannot be visually verified—requires borescope or disassembly per Porsche SIB 987/601/05.
The M 97.74's primary reliability risk is IMS bearing wear in early (2005–2006) production, with elevated incidence in track-driven or cold-start aggressive use. Porsche internal service data from 2007 noted IMS-related concerns in ~6% of pre-2007 Boxster S engines before 100,000 km under performance conditions, while UK DVSA records show strong baseline reliability in standard road applications. Extended high-RPM operation without warm-up increases thermal stress, making operating discipline critical.
Analysis derived from Porsche technical bulletins (2005-2008) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-97-74.
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