The Opel Commodore B 2.5 GS, produced between 1972 and 1975, represented a significant iteration of Opel’s flagship model. Part of the B generation (1972-1978), the 2.5 GS occupied a position as a performance-oriented variant within the Commodore lineup, aimed at buyers seeking a blend of comfort, style, and respectable power. It was primarily marketed in Europe, particularly West Germany, as a spacious and well-equipped family saloon with sporting pretensions. The Commodore B series aimed to compete with other large European saloons like the Ford Granada and Peugeot 504.
Technical Specifications
| Brand | Opel |
| Model | Commodore |
| Generation | Commodore B |
| Type (Engine) | 2.5 GS (130 Hp) |
| Start of production | 1972 |
| End of production | 1975 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 12 sec |
| Acceleration 0 – 62 mph | 12 sec |
| Acceleration 0 – 60 mph | 11.4 sec |
| Maximum speed | 180 km/h (111.85 mph) |
| Weight-to-power ratio | 9.4 kg/Hp, 106.6 Hp/tonne |
| Weight-to-torque ratio | 6.6 kg/Nm, 152.5 Nm/tonne |
| Power | 130 Hp @ 5300 rpm |
| Power per litre | 52.2 Hp/l |
| Torque | 186 Nm @ 4000-4500 rpm (137.19 lb.-ft. @ 4000-4500 rpm) |
| Engine Model/Code | 25H |
| Engine displacement | 2490 cm3 (151.95 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 87 mm (3.43 in.) |
| Piston Stroke | 69.8 mm (2.75 in.) |
| Compression ratio | 9:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | SOHC |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Kerb Weight | 1220 kg (2689.64 lbs.) |
| Max. weight | 1660 kg (3659.67 lbs.) |
| Max load | 440 kg (970.03 lbs.) |
| Trunk (boot) space – minimum | 408 l (14.41 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4607 mm (181.38 in.) |
| Width | 1728 mm (68.03 in.) |
| Height | 1405 mm (55.31 in.) |
| Wheelbase | 2668 mm (105.04 in.) |
| Front track | 1450 mm (57.09 in.) |
| Rear (Back) track | 1400 mm (55.12 in.) |
| Ride height (ground clearance) | 140 mm (5.51 in.) |
| Drag coefficient (Cd) | 0.46 |
| Minimum turning circle (turning diameter) | 11.2 m (36.75 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 4 gears, manual transmission |
| Front brakes | Disc |
| Rear brakes | Drum |
Powertrain & Engine Architecture
The heart of the Commodore B 2.5 GS was the 25H engine, a 2.5-liter (2490 cc) inline-six cylinder powerplant. This engine featured a single overhead camshaft (SOHC) valvetrain with two valves per cylinder. Fuel delivery was managed by a carburetor, a common setup for the era, rather than fuel injection. The 9:1 compression ratio contributed to the engine’s 130 horsepower output at 5300 rpm and 186 Nm (137.19 lb-ft) of torque between 4000 and 4500 rpm. The engine’s design prioritized smooth operation and reasonable power delivery over outright performance. The standard transmission for the 2.5 GS was a four-speed manual gearbox, although an automatic transmission was available as an option, albeit less common. The automatic option typically reduced horsepower slightly.
Driving Characteristics
The Commodore B 2.5 GS offered a comfortable and refined driving experience. The inline-six engine provided adequate power for cruising on the Autobahn and overtaking maneuvers, though it wasn’t a particularly sporty performer. Acceleration to 60 mph took around 11.4 seconds, and the top speed was approximately 112 mph. The four-speed manual transmission allowed for reasonable control over the engine’s power, while the optional automatic provided convenience at the expense of some responsiveness. The rear-wheel-drive configuration offered predictable handling, but the Commodore B was a relatively large and heavy car, which limited its agility. Compared to the more powerful Commodore GS/E models, the 2.5 GS prioritized fuel economy and ease of driving.
Equipment & Trim Levels
The “GS” designation indicated a higher trim level than the base Commodore. Standard equipment on the 2.5 GS typically included cloth upholstery, a wood-trimmed dashboard, and a comprehensive instrument panel. Features like a radio, whitewall tires, and a vinyl roof were often included. Optional extras could include power steering, central locking, and upgraded audio systems. The interior was designed to be spacious and comfortable, reflecting the Commodore’s role as a family saloon. The GS trim also featured some exterior enhancements, such as chrome trim and distinctive badging.
Chassis & Braking
The Commodore B utilized a traditional body-on-frame construction, providing a robust and durable chassis. The suspension consisted of independent front suspension with coil springs and a rigid rear axle with leaf springs. The front brakes were disc brakes, offering better stopping power than the drum brakes fitted to the rear wheels. Steering was of the recirculating ball type, providing a relatively heavy but precise feel. The suspension was tuned for comfort, prioritizing a smooth ride over sharp handling. Stabilizer bars were fitted to both the front and rear axles to reduce body roll during cornering.
Market Reception & Comparison
The Opel Commodore B 2.5 GS was generally well-received by automotive critics. It was praised for its spacious interior, comfortable ride, and reliable engine. However, some critics noted that the car was somewhat bland in terms of styling and lacked the sporting character of some of its rivals. Compared to the higher-performance Commodore GS/E models, the 2.5 GS offered a more affordable and fuel-efficient alternative. It also provided a more luxurious experience than the lower-spec Commodore models. Fuel economy was reasonable for the time, averaging around 20-25 mpg. Reliability was generally good, although maintenance costs could be relatively high due to the car’s size and complexity.
Legacy
The Opel Commodore B 2.5 GS remains a popular classic car among enthusiasts. The inline-six engine is known for its durability and relatively simple maintenance requirements. While not a high-performance machine by modern standards, the Commodore B 2.5 GS offers a charming and nostalgic driving experience. Finding well-maintained examples can be challenging, as many cars have been lost to rust or neglect. However, the Commodore B continues to be appreciated for its classic styling, spacious interior, and comfortable ride. Parts availability is generally good, although some specific components can be difficult to source. Today, the Commodore B 2.5 GS represents a piece of automotive history, embodying the style and engineering of the 1970s.
