Mercedes has recently published photos and a video with its one-off V8 powered, rear wheel drive B55 based on the B Class model that came to life thanks to an idea from Peter Wesp, plant manager at the Mercedes Tastatt facility.
The B 200 CDI model used as the platform for the V8 powered Mercedes B55 spins the wheels via a 7-speed automatic gearbox, and the amount of power that can be generated reaches 388 horses and 530 Nm of torque.
The Mercedes B55 5.5-litre V8 has also been fitted with a new coilover suspension from K&W, a new exhaust system, performance brakes from the C32 AMG and 18-inch 5-spoke design AMG alloys wrapped in 235/40 ZR 18 Y and 255/35 ZR 18 Y tires.    
The Mercedes B55 5.5-litre V8 tips the scale at 1,620 Kg, which means 180 Kg more than the original model, and in terms of performance the car is expected to sprint from nought to 62 mph (0 to 100 Km/h) in under 6.0 seconds.
For more details with the 5.5-litre V8 powered Mercedes B55 check out the official press release below the jump.
Mercedes-Benz press release :
B-Class with a V8 engine crafted by trainees in Rastatt

  • Fulminating one-off: B 55 with a V8 engine and 388 hp
  • Complete conversion in the training workshop

Spacious, innovative and safe, the compact models of the Mercedes A
and B-Class score with their high practicality, and have found favour
with more than 2.5 million customers as a result. An extraordinary
one-off example has now been built at the Rastatt plant, and shows the
B-Class in a completely new light: a B 55 with a V8 engine and
rear-wheel drive.
The idea came from the Rastatt plant manager, Peter Wesp. He gave
some of his staff the task of creating a very special vehicle on the
basis of the B-Class – leaving it to their creativity to decide what and
how. Andreas Würz, a foreman in the technical vocational training
department, immediately took up the challenge. He took a very close look
at this large compact model, enlisted the aid of a tape-measure and
came up with an idea that not only surprised and delighted his boss and
colleagues, but also the trainees: "Actually it should be possible to
fit a V8 into the engine compartment.“
Together with his fellow-foreman Matthias Rieger from the
electrics/electronics installation section, he assembled a team of
twelve second-year and third-year trainees specialising in production
mechanics and automotive mechatronics. A book of specifications was
drawn up:

  • The spatial concept of the B-Class was to remain unchanged.
  • On the outside too, there were only to be minor indications of the conversion work.
  • The interior was to be upgraded in line with the new vehicle class being aspired to.
  • And the result of the conversion was to be in large measure suitable for day-to-day driving.

HR manager Martin Spicale promised financial support, which made the
project a feasible proposition in the first place. And a "victim" (Würz)
for the conversion was also soon found: a B 200 CDI which had anyway
been delegated to the training workshop for learning purposes. While the
trainees completely disassembled the car, Würz went in search of a
suitable engine and found what he was looking for. And no mistake: the
5.5-litre V8 developing 388 hp and 530 newton metres of torque was
transplanted into the B-Class together with a seven-speed automatic
transmission and the engine control unit. The latter proved to be quite a
headache later on, as it had to be reprogrammed only to process signals
from the driven rear axle.
Würz: "The V8 power unit fitted amazingly well, and we were even able
to use the original engine mounts." There were serious problems with
the steering, but here too, harmony was restored with a number of
modifications. The exhaust system was a clever combination of various
replacement part items, and took the form of a twin-pipe system emerging
at the centre of the rear end. This is where the one-off, christened
the B 55 gets its typical, burbling sound – once the ignition key has
been turned, all heads in the vicinity are guaranteed to swivel
simultaneously in the direction of the B-Class.
Intensive perusal of parts catalogues also solved the second major
transplantation problem, namely the drive axle at the rear. It emerged
that the rear axle of an older W 210 series E-Class would be a very good
geometrical fit. Plant manager Wesp gave the go-ahead to obtain one,
and Würz and his colleagues designed a subframe, which extensive forming
and welding work allowed to be integrated into the B-Class bodyshell to
receive the new rear axle. Elegantly concealed within the sandwich
floor, the propshaft of the E-Class also fitted into the B-Class with no
further modifications.
For the brakes the team also struck gold in the replacement parts
catalogue, this time in the C32 AMG listing. Perforated and internally
ventilated disc brakes in size 345 x 34 mm were implanted at the front,
with perforated and internally ventilated disc brakes in size 300 x 30
mm at the rear. The system was combined with striking 8.5 x 18 AMG
sports wheels in a five-spoke design shod with 235/40 ZR 18 Y tyres at
the front and 9 x 18 wheels with 255/35 ZR 18 Y tyres at the rear. The
maximum steering angle at the front axle was limited to suit. The team
had recourse to a typical item from the tuner’s toolbox for the
suspension, installing a coil-over suspension by K&W.
Where the interior was concerned, friends from the training workshop
in Sindelfingen were able to help, providing Alcantara linings for the
A, B and C-pillars as well as a roof liner in the same, luxurious
material. The seats in a leather/Alcantara combination were provided by
the specialists at Johnson Controls, who are located on-site in Rastatt.
The finishing touches were added to the B 55 in the paint shop of the
Rastatt plant. In trendy white with dark-painted radiator louvres and
smoked headlamp lenses, the B-Class cuts an imposing figure but only
gives a discreet indication of the powerpack concealed beneath its
bonnet.
The project team headed by foreman Würz are particularly proud that
at 1620 kg, the weight of the B 55 is only around 180 kg greater than
that of the original car. Which means that impressive performance
figures can be expected. Würz: "We have not made any measurements yet,
but we should manage a sprint to 100 km/h in under six seconds."
Plant manager Wesp is equally proud of the result: "The team of
trainees has done a superb job, and placed a spotlight on the sporty
genes of the B-Class that nobody could have imagined." Training
manageress Manuela Rascher is likewise very pleased: "The B 55 shows
what our training workshop can do.
And at the same time it clearly demonstrates that we not only offer
young people high-quality professional training, but also highly unusual
and exciting project work." Could it be that further projects of this
nature are planned for the future? Rascher: "We may have some surprises
in store…"

Video : Mercedes B55 with 388 HP 5.5-litre V8 

Source: Mercedes