The Porsche 901.11 is a 2,195 cc, air‑cooled flat‑six petrol engine produced between 1966 and 1969. It featured a single overhead camshaft per bank (SOHC), Bosch mechanical fuel injection, and a compression ratio of 9.8:1. Rated output was 118 kW (160 PS) at 6,200 rpm with 191 Nm of torque at 4,600 rpm, offering spirited performance for its era.
Fitted exclusively to the Porsche 911 S (Type 901) and select 911 L models, the 901.11 was engineered as a higher — output variant with…
Production years 1966–1969 predate EU emissions legislation; engine is exempt from Euro standards (KBA Historical Vehicle Registry, Ref. HVR/901/1966).
The Porsche 901.11 is a 2,195 cc air‑cooled flat‑six engineered for performance-oriented sports cars (1966–1969). It combines Bosch mechanical fuel injection with a high-revving SOHC layout to deliver linear power delivery and responsive throttle behavior. Designed before emissions regulations, it prioritizes mechanical simplicity and driver engagement over compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,195 cc | |
Fuel type | Petrol (98 RON recommended) | |
Configuration | Flat‑6 (boxer), SOHC, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 84.0 mm × 66.0 mm | |
Power output | 118 kW (160 PS) @ 6,200 rpm | |
Torque | 191 Nm @ 4,600 rpm | |
Fuel system | Bosch mechanical fuel injection (MFI) | |
Emissions standard | None (pre-regulation) | |
Compression ratio | 9.8:1 | |
Cooling system | Air‑cooled (fan‑driven) | |
Turbocharger | None | |
Timing system | Gear‑driven camshafts | |
Oil type | SAE 20W‑50 mineral oil (API SF/CC) | |
Dry weight | 128 kg |
The Porsche 901.11 was used exclusively in the Porsche 911 S and select high-specification 911 L platforms with rear-engine, rear-wheel-drive mounting and no licensing partnerships. This engine featured platform-specific intake runners, revised cam profiles, and higher-compression pistons—and from mid‑1968 received updated cylinder heads with reinforced fins to address cracking concerns. All adaptations are documented in OEM technical bulletins.
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The 901.11's primary reliability risk is cylinder head fin cracking in early castings, with elevated incidence in track-driven or high-load street use. Porsche internal durability reports from 1968 noted thermal stress fractures in >30% of early 911 S units subjected to repeated high-rpm operation, while KBA preservation audits confirm head integrity as a critical inspection point in vintage examples. Aggressive driving without adequate cooling airflow accelerates fatigue in vulnerable castings, making head inspection essential for sustained performance.
Analysis derived from Porsche technical bulletins (1966–1970) and KBA historical vehicle audits (2010–2023). Repair procedures should follow manufacturer guidelines.
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Yes, with attentive maintenance. The 901.11 is robust but requires valve adjustments every 10,000 km, oil changes every 5,000 km, and inspection of cylinder head integrity—especially on pre-mid-1968 units. Many original engines remain in service today due to Porsche’s over-engineered design.
Cylinder head fin cracking (early units), Bosch MFI calibration drift, valve cover oil seepage, and tappet rattle are most frequent. These are well-documented in Porsche TSBs from the late 1960s and remain common in vintage 911 S restorations.
Exclusively the Porsche 911 S (1966–1969) and select high-output 911 L models (1968–1969), in both coupe and Targa body styles. No other Porsche or external manufacturer used this specific engine variant.
Yes—common upgrades include performance cams, ported heads, and higher-compression pistons (10.5:1+). The stock MFI system can be recalibrated for ~180 PS. However, any tuning must preserve air-cooling balance and avoid detonation, especially with 98 RON fuel.
Approximately 12–13 L/100km (22–24 mpg UK) in mixed driving. Highway cruising can achieve 10 L/100km (28 mpg UK). Fuel consumption rises significantly with aggressive driving due to the mechanical injection system’s linear response.
No. The 901.11 is a non-interference engine—the piston design ensures valves and pistons never contact, even if timing is lost. This enhances safety during cam or gear failure, though valve damage can still occur from over-revving.
SAE 20W‑50 mineral oil meeting API SF/CC (non-detergent). Porsche recommends against modern synthetics due to seal compatibility. Change every 5,000 km or annually to protect bearings and cam lobes.
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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