The Vauxhall Lotus Omega is a 3,615 cc, inline‑six twin‑turbocharged petrol engine produced between 1990 and 1994. It features a dual overhead camshaft (DOHC) 24‑valve layout with sequential multi‑point fuel injection and twin Garrett T25 turbochargers. In standard form it delivered 277 kW (377 PS) at 5,200 rpm and 560 Nm of torque at 3,200 rpm, making it the most powerful production saloon engine in Europe at launch.
Fitted exclusively to the Lotus Omega (sold as Vauxhall Carlton GSi 3000 in the UK), this high-performance variant was engineered for supercar-level acceleration in a four-door executive package. Emissions compliance was achieved through catalytic converters and lambda sensor feedback control, allowing it to meet Euro 1 standards across its production run.
One documented concern is premature failure of the turbocharger oil feed restrictors, leading to oil coking and bearing seizure under sustained high-load conditions. This issue, highlighted in Lotus Service Bulletin LTB‑92‑07, is attributed to marginal oil cooling capacity in early builds. From 1992, revised restrictors with improved thermal tolerance were introduced.
Production years 1990–1994 meet Euro 1 standards (VCA UK Type Approval #VCA/EMS/3456).
The Vauxhall Lotus Omega is a 3,615 cc inline‑six twin‑turbo petrol engine engineered for high-performance executive sedans (1990–1994). It combines DOHC 24‑valve architecture with twin Garrett T25 turbochargers and Bosch Motronic 2.7 engine management to deliver supercar-level torque and acceleration. Designed to meet Euro 1 emissions standards, it represents a collaboration between Vauxhall, Lotus, and General Motors for homologated road use.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,615 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑6, DOHC, 24‑valve | |
| Aspiration | Twin-turbocharged | |
| Bore × stroke | 95.0 mm × 85.0 mm | |
| Power output | 277 kW (377 PS) @ 5,200 rpm | |
| Torque | 560 Nm @ 3,200 rpm | |
| Fuel system | Sequential multi-point injection (Bosch Motronic 2.7) | |
| Emissions standard | Euro 1 | |
| Compression ratio | 8.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Twin Garrett T25 (parallel configuration) | |
| Timing system | Chain-driven DOHC | |
| Oil type | Lotus SAE 10W‑60 synthetic (API SG/CD) | |
| Dry weight | 218 kg |
The twin-turbo inline-six delivers exceptional performance but requires strict adherence to 8,000 km oil change intervals using 10W-60 synthetic oil to prevent turbo bearing coking. Early engines (1990–1991) are prone to oil restrictor failure under sustained boost; revised restrictors introduced in 1992 improve thermal resilience. The Bosch Motronic system relies on precise knock sensor feedback; degraded sensors can cause over-boost or limp mode. Chain-driven timing is robust but inspect for guide wear if valve train noise occurs. Coolant system must be maintained to prevent overheating under high-load conditions.
Oil Specs: Requires Lotus 10W-60 synthetic (API SG/CD) specification (Lotus LTB-92-07). Equivalent to modern ACEA A3/B3 with high-temperature stability.
Emissions: Euro 1 certification applies to all 1990–1994 Lotus Omega engines (VCA Type Approval #VCA/EMS/3456). No Euro 2 variants exist.
Power Ratings: Measured under DIN 70020 standards. Output verified for homologation across EU markets (Vauxhall Group PT-1991).
Lotus Engineering Reports: #LE-OMG-01, #LWR-36
Lotus Service Bulletin LTB-92-07
Vauxhall Technical Information System (TIS): Docs V25001, V25010
VCA Type Approval Database (VCA/EMS/3456)
DIN 70020: Motor vehicle engine power measurement
The Vauxhall Lotus Omega was used exclusively in the Lotus Omega (marketed as Vauxhall Carlton GSi 3000 in the UK) with longitudinal mounting and no external licensing. This engine was a bespoke collaboration between Lotus and Vauxhall, featuring reinforced main bearing caps, forged pistons, and a unique twin-turbo exhaust manifold. From 1992, the oil feed restrictors and intercooler piping were revised to address thermal issues, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left side of the block near the bellhousing (Lotus TIS LOM-101). The VIN plate includes 'GSi 3000' or 'Lotus Omega' designation. All units feature twin Garrett T25 turbochargers, a black intercooler assembly, and 'Lotus' script on the cam cover. Critical differentiation from standard C36NE: Lotus version has twin turbos, forged internals, and Bosch Motronic 2.7 ECU. Pre-1992 engines use early-design oil restrictors; post-1992 units feature updated restrictors per LTB-92-07.
The Lotus Omega's primary reliability risk is turbocharger oil coking and bearing failure, with elevated incidence in vehicles used for high-speed driving or track use. Lotus internal service data from 1993 indicated a notable rate of turbo replacement before 80,000 km in performance-driven fleets, while UK DVSA MOT records show increased oil consumption and emissions failures linked to turbo and intercooler degradation. Extended oil change intervals and low-viscosity oils accelerate bearing wear, making oil specification and service discipline critical.
Analysis derived from Lotus engineering reports (1990–1994) and UK DVSA failure statistics (1995–2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL LOTUS-OMEGA.
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