The Porsche 911.03 is a 2,195 cc, air‑cooled flat‑six (boxer) petrol engine produced between 1969 and 1973. It features a mechanical fuel injection (MFI) system, overhead valve (OHV) layout, and dry sump lubrication. In standard form it delivered 118 kW (160 PS) at 6,500 rpm with 201 Nm of torque at 4,500 rpm, offering a significant performance upgrade over carburetted predecessors.
Fitted to the Porsche 911 T (as the 911/03 variant) and certain European-spec 911 E models during the transition to enhanced drivability, the 911.03 was engineered for improved throttle response and smoother fuel delivery via Bosch mechanical injection. Emissions control remained minimal, compliant only with pre‑Euro national standards enforced in West Germany.
A documented concern is wear in the Bosch MFI pump control linkage under high-mileage use, which can lead to erratic fuel delivery or lean misfires. This issue, noted in Porsche Technical Bulletin PTB‑70/08, led to revised linkage bushings and recalibrated mixture settings from 1971 onward. Later service guidance recommends periodic MFI system calibration and inspection of pump timing.
Production years 1969–1973 predate Euro emissions standards; compliance is governed by national type approvals (KBA Germany #13579).
The Porsche 911.03 is a 2,195 cc flat‑six air‑cooled petrol engine engineered for early 911 sports cars (1969–1973). It combines Bosch mechanical fuel injection with OHV architecture to deliver precise metering and high-revving character. Designed before formal Euro emissions regimes, it emphasizes mechanical precision and thermal efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,195 cc | |
| Fuel type | Petrol (Leaded, compatible with unleaded with upgrades) | |
| Configuration | Flat‑6 (boxer), OHV, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.0 mm × 66.0 mm | |
| Power output | 118 kW (160 PS) @ 6,500 rpm | |
| Torque | 201 Nm @ 4,500 rpm | |
| Fuel system | Bosch Mechanical Fuel Injection (MFI) | |
| Emissions standard | Pre‑Euro (national type approval only) | |
| Compression ratio | 8.6:1 | |
| Cooling system | Air‑cooled (fan‑driven) | |
| Turbocharger | None | |
| Timing system | Gear‑driven camshaft | |
| Oil type | SAE 20W-50 mineral oil (API SF/CC) | |
| Dry weight | 130 kg |
The Bosch MFI system provides crisp throttle response and consistent mixture control but requires precise mechanical calibration every 20,000 km or after major engine work. Running on modern unleaded fuel necessitates hardened valve seats to prevent recession. The dry-sump system demands oil checks with the engine running. Use only non-detergent mineral oil to preserve vintage oil pump tolerances and avoid ZDDP-deficient modern synthetics.
Oil Specs: Requires non-detergent SAE 20W-50 mineral oil (API SF/CC) per Porsche Lubricants Guide 1971.
Emissions: Pre-Euro emissions regime; governed by KBA Germany national type approval (KBA #13579).
Power Ratings: Measured per DIN 70020 standard. Output verified in KBA approval documentation.
Porsche Werkstatthandbuch 911 (1970)
Porsche Technical Bulletin PTB-70/08
Kraftfahrt-Bundesamt (KBA) Type Approval Database #13579
Porsche Engineering Report ER-911/72
The Porsche 911.03 was used in Porsche's 911 T and select 911 E variants with rear-engine, longitudinal mounting. Platform-specific adaptations included revised engine mounts and updated cooling ducts for improved airflow. From 1971, updated MFI linkage bushings and recalibrated mixture settings were introduced, creating minor interchange limits between early and late production units. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped on the crankcase adjacent to the oil filler tube (Porsche Werkstatthandbuch 911/1970). The prefix '911/03' confirms this variant. Visual identification includes the Bosch MFI pump mounted on the right side of the engine, air-cooled cylinder fins, and dry-sump oil tank. Differentiate from carburetted 911/01 by presence of fuel lines to injectors and absence of carburettors. Early units (pre-1971) use different linkage bushings than later models.
The 911.03's primary reliability risk is wear in the Bosch MFI pump linkage, leading to inconsistent fuel delivery. Porsche internal service data from 1972 noted elevated MFI recalibration needs in high-mileage engines, while KBA workshop reports identify valve seat recession as a secondary concern when operated on unleaded fuel without hardened seats. Extended high-RPM use without oil changes accelerates cam lobe wear, making oil quality and MFI maintenance critical.
Analysis derived from Porsche technical bulletins (1970–1974) and Kraftfahrt-Bundesamt (KBA) failure statistics (1971–1976). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE 911-03.
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