Mercedes-Benz B55 (2010)

The Mercedes-Benz B55, built in 2010, is one of the most fascinating and unexpected sleepers ever created — a one-off engineering project that saw a compact Mercedes B-Class transformed into a V8-powered monster. Developed not as a production model but as an internal experiment by Mercedes-Benz trainees and engineers at the Rastatt plant, the B55 project blended humor, absurdity, and serious technical skill into a fully functional hot hatch that defied every expectation.

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History

The B-Class had always been a practical, family-oriented compact MPV, designed for efficiency, safety, and versatility — not for performance. But at the Mercedes-Benz Rastatt plant, a group of twelve apprentices and their supervisors decided to create something completely different for a training project.

The idea was simple yet insane:

• Take a B-Class shell

• Shoe-horn in a massive 5.5-liter V8 engine from the E55 AMG

• Convert the front-wheel-drive platform to rear-wheel drive

• Reinforce everything to handle the power

The result was the B55, a fully engineered, road-going machine capable of shocking any unsuspecting opponent at a traffic light. Although never intended for public sale, the project received official Mercedes-Benz support as an internal showcase of engineering creativity and technical ability.

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Design Features

Visually, the B55 looked surprisingly stock, maintaining the discreet appearance of a normal B-Class. This "sleeper" nature made the project even more charming.

Subtle changes included:

• Slightly lowered suspension

• Wider wheels and tires for grip

• Twin exhaust outlets integrated neatly into the rear bumper

• B55 badges discreetly placed at the rear

Inside, the cabin was similarly unassuming, with minor upgrades like AMG-style seats and a revised instrument cluster to reflect the vastly increased performance. Most of the practicality and functionality of the original B-Class was retained — it remained a five-door hatchback with real seating and cargo space.

The true magic was hidden under the skin, where the drivetrain, suspension, and brakes were entirely reworked to cope with V8 power.

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Specs

The heart of the B55 was the M113 5.5-liter naturally aspirated V8, sourced from the E55 AMG (pre-supercharged models).

Key specifications:

• Engine: 5.5-liter M113 V8, naturally aspirated

• Power: ~388 horsepower

• Torque: ~530 Nm (391 lb-ft)

• Transmission: 5-speed automatic from the E-Class

• Drivetrain: Rear-wheel drive

• Suspension: Custom, adapted from C-Class W203

• Brakes: AMG high-performance braking system

• 0–100 km/h: Estimated under 5.0 seconds

• Top speed: Limited to 250 km/h (155 mph)

To fit the V8, engineers had to heavily modify the engine bay, firewall, and transmission tunnel, reinforcing the chassis to maintain rigidity. The rear axle came from a W210 E-Class, enabling proper rear-wheel-drive dynamics.

Despite all these changes, the B55 weighed around 1,620 kg, making it relatively light for the power it produced.

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Production Status

The Mercedes-Benz B55 was strictly a one-off prototype, built as a passion project and engineering exercise. It was never homologated for production, nor was it road-certified beyond internal use and demonstration events.

However, the car was fully functional, drivable, and tested extensively. It appeared in various automotive media articles and exhibitions as a symbol of what Mercedes engineers could create when freed from corporate constraints.

The B55 remains part of Mercedes-Benz’s internal collection, celebrated among enthusiasts as one of the coolest "what if" cars ever built — a proper wolf in sheep’s clothing.