What is it?
The B 55 is not a regular Mercedes-Benz model. Nor is it being considered for sale – not now or at any time in the future. Sadly, I should add. Because this wild take on the otherwise wholesomely conservative B-class, created by a team of trainees at Mercedes' Rastatt factory in Germany, is an absolute riot.
As its name suggests, the superbly constructed one-off prototype is well removed from the standard B-class. Having started off life as a humble B 200 CDI, it has been liberated from its standard turbocharged 2.0-litre four-cylinder diesel engine. Shoehorned into its place and other areas of the engine bay is Mercedes’ recently superseded 5.5-litre petrol V8 packing an added 243bhp at 383bhp and 170lb ft more torque at 391lb ft.
What's it like?
Just how the new engine fits under the heavily sloping bonnet and within the tight confines of the compact MPV using the original mounts and without any modification to the standard steel body structure remains somewhat of a mystery, but with polished chrome inlet plumbing and other visual tweaks, it certainly looks the goods.
It sounds it, too. Turn the key and you’re treated to a deliciously throaty soundtrack thanks to a new exhaust system created from various replacement parts that does without the usual silencers and back-pressure reducing trickery. If you didn't know, you could be forgiven for thinking it was the product of AMG, which apparently had no direct input into the new car.
The engine is not the only highlight. Mercedes' trainees have also ditched the B-class's front-wheel drive layout for rear-wheel drive, running a propshaft from its new seven-speed automatic gearbox under the flat floor towards the rear where it mates with an axle from the old E 430 Estate; Its 1540mm rear track allowed them to retain standard rear bodywork but required new pick-up points for the rear multi-link suspension and a smaller fuel tank.
To cope with the increased performance, it also adopts the brakes from the decade-old C 32 AMG with 345mm discs up front and 300mm at the rear. Because of the limited development, though, there's no traction control or stability program to corral the engine's reserves.