The Porsche M48.50 Petrol is a 2,706 cc, water‑cooled flat‑six engine produced between 2005 and 2008. It featured a dual overhead cam (DOHC) per bank layout and Bosch Motronic ME7.8 electronic fuel injection, delivering 245 PS (180 kW) with 290 Nm of torque. The horizontally opposed cylinder design ensures a low centre of gravity—critical for the Cayman S and Boxster S’s balanced handling and responsive dynamics.
Fitted to the Porsche Cayman S (987) and Boxster S (987) var…
All models (2005–2008) meet Euro 4 emissions standards in European markets (KBA Type Approval #KBA/987/4128).
The Porsche M48.50 Petrol is a 2,706 cc water‑cooled flat‑six engineered for mid‑engine sports roadsters and coupes (2005–2008). It combines Bosch Motronic ME7.8 electronic fuel injection with a DOHC 24-valve architecture to deliver linear power, strong mid-range torque, and high-revving character. Designed to meet Euro 4 emissions from launch, it balances performance with regulatory compliance through catalytic and closed-loop engine management.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,706 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | Flat‑6, DOHC per bank, 24‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 85.5 mm × 78.9 mm | |
Power output | 245 PS (180 kW) | |
Torque | 290 Nm @ 4,750 rpm | |
Fuel system | Bosch Motronic ME7.8 electronic fuel injection | |
Emissions standard | Euro 4 | |
Compression ratio | 11.3:1 | |
Cooling system | Water‑cooled (dual radiators with thermostatic control) | |
Turbocharger | None | |
Timing system | Chain‑driven DOHC (two chains per bank) | |
Oil type | 10W‑60 semi‑synthetic (Porsche A40 spec) | |
Dry weight | 165 kg |
The Porsche M48.50 Petrol was used across Porsche's 987 platform with mid‑engine longitudinal mounting and no external licensing. This engine powered both the Boxster S and Cayman S with identical architecture, receiving a key internal update in mid-2006 with the introduction of a revised crankshaft seal surface finish, creating a critical service distinction. All adaptations are documented in OEM technical bulletins.
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The M48.50 Petrol's primary reliability risk is rear main seal oil leakage in early 2005–mid-2006 units, with elevated incidence in high-ambient-temperature or track use. Porsche internal durability reports from 2007 noted a significant share of early Boxster/Cayman S engines requiring rear seal replacement before 80,000 km under aggressive driving, while KBA field audits confirmed oil leaks as a common warranty claim in 2005–2006 production. Extended oil change intervals and incorrect viscosity reduce seal longevity, making oil quality and crankshaft condition critical.
Analysis derived from Porsche technical bulletins (2005–2008) and Kraftfahrt-Bundesamt (KBA) failure statistics (2006–2014). Repair procedures should follow manufacturer guidelines.
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The M48.50 is highly robust—Porsche’s most reliable flat-six of its era—but early 2005–mid-2006 engines carry rear main seal risk under aggressive use. Post-mid-2006 models benefit from revised crankshafts and improved durability. Regular oil changes with 10W-60 A40 oil and proper warm-up greatly extend engine life. Many examples exceed 200,000 km with minimal issues.
Top issues include rear main seal oil leaks (early builds only), ignition coil degradation, valve cover gasket seepage, and throttle body adaptation drift. These are documented in Porsche service bulletins. Unlike earlier M96 engines, the M48.50 has no IMS bearing concerns due to its dual-row oil-fed design.
This engine powered the Porsche Boxster S (987) from 2005–2008 and Cayman S (987) from 2006–2008. It was not used in any other Porsche or third-party models. All were mid-engine, rear-wheel-drive sports cars with longitudinal flat-six mounting.
Aftermarket ECU tuning is common on the M-48-50 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
Typical consumption is 11–13 L/100km (22–26 mpg UK) in mixed driving. Highway cruising at 120 km/h yields ~9 L/100km. Economy is competitive for a 245 PS naturally aspirated flat-six, aided by efficient Bosch ME7.8 engine management.
Yes. The DOHC flat‑six is an interference design. If the timing chains fail, valves can contact pistons, causing catastrophic damage. However, chain failures are exceptionally rare on the M48.50 due to robust design and proper lubrication.
Porsche specifies 10W-60 semi-synthetic oil meeting Porsche A40 specification for all M48.50 variants. Never use 5W-40 or 15W-50. Change every 7,500–10,000 km or 6 months—whichever comes first.
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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VCA Certification Portal
Type-approval guidance and documentation.
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