The Porsche 930.66 is a 3,164 cc, air-cooled flat‑six turbocharged petrol engine produced between 1984 and 1989. It features a single KKK K27 turbocharger, Bosch Motronic digital fuel injection, and an air-cooled crankcase with oil-cooled cylinder heads. Output was standardized at 221 kW (300 PS), delivering improved driveability and smoother boost delivery compared to earlier mechanical-injection 930 variants.
Fitted exclusively to the 911 Turbo (930) for markets requiring stricter emissions compliance—particularly the US and Japan—the 930.66 was engineered for enhanced drivability without sacrificing performance. Emissions compliance was achieved through a three-way catalytic converter, lambda sensor feedback, and exhaust gas recirculation, meeting US EPA/DOT and transitional EU Directive 83/351/EEC standards.
One documented concern is premature wear of the exhaust valve seats due to high combustion temperatures under sustained boost, highlighted in Porsche Technical Service Bulletin 911/TSB/87-12. This was exacerbated in high-ambient-temperature regions and led to compression loss. From 1987, Porsche introduced hardened valve seat inserts and revised ignition timing maps to mitigate this issue.
Production years 1984–1989 meet US EPA/DOT (Federal Tier 0) and EU transitional emissions standards (Directive 83/351/EEC) depending on market (VCA Type Approval #VCA/EMS/8215).
The Porsche 930.66 is a 3,164 cc air-cooled flat-six turbocharged petrol engine engineered for high-performance GT applications (1984–1989). It combines Bosch Motronic digital fuel injection with a single KKK turbocharger to deliver smoother low-end response and precise emissions control. Designed to meet US EPA and transitional EU emissions standards, it balances analog driving feel with digital-era compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,164 cc | |
| Fuel type | Petrol (RON 98 minimum recommended) | |
| Configuration | Flat‑6, OHC, 12‑valve | |
| Aspiration | Turbocharged (KKK K27) | |
| Bore × stroke | 98.0 mm × 69.6 mm | |
| Power output | 221 kW (300 PS) @ 5,500 rpm | |
| Torque | 412 Nm @ 4,000 rpm | |
| Fuel system | Bosch Motronic 2.1 digital electronic injection | |
| Emissions standard | US EPA Tier 0 / EU Directive 83/351/EEC (transitional) | |
| Compression ratio | 7.2:1 | |
| Cooling system | Air-cooled block, oil-cooled heads | |
| Turbocharger | Single KKK K27 (non-water-cooled CHRA) | |
| Timing system | Gear-driven intermediate shafts (no timing belt/chain) | |
| Oil type | SAE 15W-50 synthetic (Porsche A40 spec) | |
| Dry weight | 228 kg |
The Motronic system provides smoother throttle response and better cold-start behavior than K-Jetronic, but demands a fully functional O2 sensor and catalytic converter for closed-loop operation. Strict adherence to 7,500 km oil changes using high-zinc 15W-50 oil is essential to protect valve train components under high boost. Exhaust valve seat recession remains a risk in hot climates; upgraded inserts per TSB 911/TSB/87-12 are recommended during rebuilds. Allow 2–3 minutes of idling post-drive to prevent turbo oil coking.
Oil Specs: Requires Porsche A40–compliant 15W-50 with ZDDP for flat-tappet cam and valve seat protection (Porsche Lubricants Bulletin LB-86-09).
Emissions: Meets US EPA Tier 0 and EU Directive 83/351/EEC (VCA Type Approval #VCA/EMS/8215). Catalytic converter mandatory for compliance.
Power Ratings: Measured under DIN 70020. Output assumes RON 98 fuel and functional lambda control (Porsche TIS Doc. 930-TB-1987).
Porsche Technical Information System (TIS): Docs 930-TB-1984, FI-84-11, 930-TB-1987
Porsche Technical Service Bulletin 911/TSB/87-12
VCA Type Approval Database (VCA/EMS/8215)
EU Directive 83/351/EEC
The Porsche 930.66 was used exclusively in the Porsche 930 platform with rear-engine, longitudinal mounting and no external licensing. This engine was developed specifically for emissions-regulated markets (US/Japan) and features catalytic converters, lambda sensors, and revised cam timing—differentiating it from the European 930.09. From 1989, the 964 Turbo replaced both variants. All adaptations are documented in OEM technical bulletins.
Engine type ‘930.66’ is cast into the left-side crankcase near the oil filler tube (Porsche WIS 135.01). The presence of a three-way catalytic converter and oxygen sensor wiring distinguishes it from non-cat 930.09 units. US-market VINs begin with ‘WP0’ and include federal emissions labeling under the hood. The DME control unit (Bosch 0 261 200 189) and lack of thermal reactors confirm 930.66 identity. Service parts for fuel and emissions systems are not interchangeable with European-spec engines (Porsche TSB 911/TSB/86-04).
The 930.66's primary reliability risk is exhaust valve seat wear in high-temperature or high-load conditions, with elevated incidence in desert climates and track use. Porsche internal service reports (1988) indicated valve jobs in over 12% of US-spec engines before 100,000 km, while DVSA historic data shows frequent catalytic converter failures in UK-registered examples due to unburned fuel from cold enrichment. Extended boost cycles and inadequate cooldown make oil quality and post-drive idle critical.
Analysis derived from Porsche technical bulletins (1984–1989) and UK DVSA historic MOT failure statistics (1992–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE 930-66.
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