Mercedes-Benz Once Shoved A V8 Into Its Tiniest MPV To Create An Absolute Monster

In the world of minivans, the Mercedes-Benz R63 AMG is widely known as the king. A strange MPV with a thumping hand-built V8 heart, every brave soul who dared to be different and bought one instead of a fast SUV effectively did a public service. However, the R63 AMG technically isn’t the only people carrier with a V8 and an AMG badge. No, it’s not some sort of special-order Sprinter, nor one of the smaller vans. Instead, it’s a one-off special exercise based around the positively compact B-Class.

America only got one generation of B-Class, and it received it in an incredibly weird way. Instead of the normal range of four-cylinder engines, the B250e featured an electric drivetrain sourced from Tesla. It was a particularly unusual compliance car sold to meet electric vehicle mandate requirements, but it’s not the strangest B-Class. Not even close.

The weirdest B-Class ever built wasn’t a development mule, or even a full-fledged feasibility study. The B55 AMG was simply a case of 12 apprentices running absolutely wild with the parts bin. The sort of Frankenstein’s Monster you’d see in Car Craft, if Car Craft was a German publication.

So how did the B55 AMG come to fruition? Well, it started life as a first-generation B200 CDI, which would normally come equipped with a 138-horsepower two-liter OM640 turbodiesel engine hitched to either a six-speed manual gearbox or a CVT. Economical? Sure. Performance-oriented? Not exactly. Picture zero-to-62 MPH in 9.6 seconds.

The crown jewel of this exercise is a V8 that wasn’t an actual AMG V8. While Mercedes-Benz’s high-performance arm did offer a handbuilt naturally aspirated 5.4-liter M113 V8 in the SLK 55 AMG of the time, the team ended up going with something a little bit more powerful than that aged-if-bulletproof 354-horsepower motor. Instead, they chose the M273 V8 you’d find in a period E550 or S550, a 32-valve 5.5-liter unit pumping out 382 horsepower and 391 lb.-ft. of torque.

That’s all well and good, but there’s one problem: The B-Class was designed right from the beginning for front-wheel drive with an engine that points east-to-west. The M273 V8, on the other hand, was designed to point north-to-south and primarily drive the rear wheels of whatever vehicle it was mounted in. To solve this, the trainees took the entire rear cradle from a W211 E-Class and grafted it into the back of the B55. Subframe, suspension arms, differential, the lot. A custom driveshaft connected the rear differential with the marque’s 7G-Tronic seven-speed automatic transmission, while brakes from the old C32 AMG were tasked with stopping the thing. Or keeping the front wheels locked while absolutely roasting the rears.

Probably because the B55 AMG was built on a shoestring budget, it features zero driver aids of any kind. No stability control, no traction control, not even anti-lock brakes. However, it can still fling itself from zero-to-62 MPH in fewer than six seconds on its way to a terminal velocity of 167 MPH. Alarmingly potent stuff from a car originally designed to be like a nicer alternative to a Ford C-Max.

Perhaps best of all, it still looks wonderfully subtle. Those AMG wheels still fit inside the factory arches despite what appears to be a significantly wider track. The bumpers are just about bog-standard aside from a custom rear valence insert to accommodate twin exhaust tips. Up front, this thing’s only tell is its blacked-out pair of headlamp buckets, which, from enough of a distance, could just look like aftermarket specials.

The Mercedes-Benz B55 AMG was a glorious prototype, probably entirely unsuitable for mass production but still the sort of stuff car enthusiast dreams are made of. Take a small, strange car and make it go rather quickly. Do I wish there was more than one in existence? Obviously, but it’s so joyful that even the one was made. Bravo, team of trainees. Now that’s a work project.

Top graphic image: Mercedes-Benz