The Porsche M 97.70 is a 3,800 cc, dual-overhead-cam flat‑six petrol engine produced between 2005 and 2008. It featured Bosch Motronic ME7.8.1 sequential fuel injection, an aluminum block with Nikasil-coated cylinders, and a dry‑sump lubrication system. In standard form it delivered 294 kW (400 PS) and 420 Nm of torque, offering high-revving performance with aggressive throttle response for the 997-generation 911 Turbo.
Fitted exclusively to the 997-generation 911 Turbo (2005–2008), the M 97.70 was engineered as Porsche’s first twin-turbocharged water-cooled flat-six for the 911 platform, blending track capability with daily usability. Emissions compliance was achieved through close-coupled catalytic converters, secondary air injection, and variable valve timing (VarioCam Plus), meeting Euro 4 standards across its production life.
One documented concern is premature wear of the intermediate shaft (IMS) bearing, inherited from earlier M96 architecture but mitigated in later builds. Porsche Technical Bulletin PTB/997/06 notes that early M 97.70 units retained the single-row IMS bearing, which is susceptible to lubrication starvation under sustained high-RPM or track use.
Production years 2005–2008 meet Euro 4 standards (TÜV Certificate TÜV/05/M97/12).
The Porsche M 97.70 is a 3,800 cc flat‑six petrol engine engineered for the rear-mounted 997 911 Turbo (2005–2008). It combines DOHC architecture with twin parallel turbochargers and sequential fuel injection to deliver explosive mid-range thrust and sustained high-RPM power. Designed to meet Euro 4 emissions standards, it integrates catalytic converters, VarioCam Plus, and dry-sump lubrication for both performance and compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,800 cc | |
| Fuel type | Petrol (RON 98 min) | |
| Configuration | Flat‑6, DOHC, 24‑valve | |
| Aspiration | Twin‑turbocharged | |
| Bore × stroke | 99.0 mm × 81.5 mm | |
| Power output | 294 kW (400 PS) @ 6,000 rpm | |
| Torque | 420 Nm @ 2,200–4,800 rpm | |
| Fuel system | Bosch Motronic ME7.8.1 sequential injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Twin parallel K16 turbochargers (BorgWarner) | |
| Timing system | Chain-driven DOHC with VarioCam Plus | |
| Oil type | Porsche C3 5W‑40 (API SM/ACEA C3) | |
| Dry weight | 172 kg |
The twin-turbo flat-six delivers explosive mid-range torque and high-RPM power ideal for both track and road use. However, the single-row IMS bearing in early units (2005–mid-2006) remains vulnerable to lubrication starvation under sustained boost or track use. Use only RON 98 fuel to prevent knock and protect catalytic converters. Oil changes every 10,000 km with Porsche C3 5W‑40 are essential to maintain turbo bearing and IMS health. Post-drive cooldown (60 seconds idle) is advised after high-load driving. Per PTB/997/06, engines produced after 08/2006 received a dual-row IMS bearing upgrade.
Oil Specs: Requires Porsche C3 5W‑40 meeting ACEA C3/API SM (Porsche Lubricants Bulletin LB-997-05). Low-SAPS formulation is mandatory for turbo and catalyst protection.
Emissions: Euro 4 compliance applies to all 2005–2008 models (TÜV Certificate TÜV/05/M97/12).
Power Ratings: Measured under DIN 70020; verified on dynamometer at 0.8 bar boost per Porsche PTB/997/06.
Porsche Technical Information System (TIS): Docs 997-05, 997-1120, 997-1145, 997-2210
Porsche Technical Bulletin PTB/997/06
TÜV Certificate TÜV/05/M97/12
Porsche Lubricants Bulletin LB-997-05
The Porsche M 97.70 was used exclusively in Porsche's 997 platform with rear-mounted, longitudinal flat-six mounting and no external licensing. This engine received platform-specific adaptations—revised turbo ducting in the 2007 model year and updated intercooler routing in 2008 models—and from 2009 was succeeded by the M 97.71 with direct fuel injection and revised turbos, creating clear generational boundaries. All adaptations are documented in OEM technical bulletins.
Engine code 'M 97.70' is stamped on the rear crankcase flange near the flywheel housing (Porsche TIS 997-1120). The 10th VIN digit indicates model year ('5' = 2005, '6' = 2006, etc.). Visual cues: black valve covers with “911 Turbo” script, twin intercoolers in rear quarter panels, and quad exhaust tips. Turbo identification: twin BorgWarner K16 units (part #997 106 201 00). Early engines (2005–08/2006) use single-row IMS bearing (part #997 106 051 00); post-08/2006 units feature dual-row bearing (part #997 106 051 01) per PTB/997/06.
The M 97.70's primary reliability risk is intermediate shaft (IMS) bearing wear in early production units (2005–mid-2006), with elevated incidence in track or hot-climate use. Porsche internal data (2007) indicated a 6% premature failure rate in pre-upgrade engines before 80,000 km, while TÜV Germany MOT records show elevated oil contamination rates in high-mileage examples. Sustained high-load operation without cooldown periods accelerates thermal stress, making IMS upgrades and post-drive idle critical.
Analysis derived from Porsche technical bulletins (2005–2008) and TÜV Germany failure statistics (2007–2017). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-97-70.
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