At first glance, the Bugatti Type 51 Grand Prix car looks nearly identical to the company’s earlier Type 35, a car that dominated European motor racing in the latter half of the 1920s. Under the hood, however, the two cars are distinctly different.
Built strictly for Grand Prix racing, the Type 51 was an evolution of the highly successful Type 35B. A major difference between the two cars is the twin-overhead block which was included on the Type 51. This head was remarkably similar to the Miller 91 design which Ettore had studied and applied to cars such as Type 50. With this cylinder head, Bugatti found an additional 20 horsepower. 187 horsepower (140 kW) was attained when running the same engine on alcohol. A victory in the 1931 French Grand Prix was a rare case of success for the line.
The obvious external differences of a Type 51 are: the supercharger blow-off outlet is lower the bonnet in the louvered section; one piece cast wheels instead of bolted on rims; twin fuel caps behind the driver and finally the magneto being off-set to the left on the dash. However many Type 35 cars have been fitted with later wheels, so that is not a reliable signal.
Engine
Configuration
Straight 8
Location
Front, longitudinally mounted
Construction
cast-iron block and head
Displacement
2,261 cc / 138 cu in
Bore / Stroke
60.0 mm (2.4 in) / 100.0 mm (3.9 in)
Compression
7.5:1
Valvetrain
2 valves / cylinder, DOHC
Camshaft
Shaft driven
Fuel feed
Zenith Carburettor
Lubrication
Dry sump
Aspiration
Roots-Type Supercharger
Power
185 bhp / 138 kW @ 5,500 rpm
BHP/Liter
82 bhp / liter
Drivetrain
Body
aluminium
Chassis
steel ladder frame
Front suspension
rigid axle, semi-elliptic springs
Rear suspension
live axle, reversed quarter elliptic springs
Brakes (fr/r)
cable operated drums
Gearbox
4 speed Manual
Drive
Rear wheel drive
Dimensions
Weight
750 kilo / 1,654 lbs
Wheelbase / Track (fr/r)
2,400 mm (94.5 in) / 1,200 mm (47.2 in) / 1,200 mm (47.2 in)
