Prototech Rennfahrzeugbau, an Austrian tuner specializing in competition, is back in the news with a radical interpretation of the Alfa Romeo 75 Turbo. The secret? The integration of a "rare" engine, based on an Autodelta 16-valve cylinder head, with a turbo preparation.
A very special engine from Autodelta
Autodelta, the historic arm of the competition Alfa RomeoAt the end of the 1970s and beginning of the '80s, he worked on a 16-valve version of the Twin Cam 4-cylinder aluminum engine, better known under the legendary name of Bialbero. An avant-garde engine with a very sporty philosophy, inspired by racing, but which had already been fitted to production cars in the 50s. To counter the growing competition from Ford Cosworth and BMW engines in touring car racing, Autodelta planned a 16-valve version. The production Alfa Romeo 75, including the Turbo Evoluzione variant, had to make do with 8-valve engines for cost reasons. Autodelta therefore produced a limited number of 16-valve cylinder heads for competition.
Specific and rare pieces
The engines featured a wide, competition-style cylinder head cover, special pent-roof combustion chambers with central spark plugs for optimum combustion, high-velocity intake ducts, higher air flow and higher revs, climbing to 8500/9000 rpm.
The precious character of these Autodelta engines comes from both their rarity and their handcrafted, handmade nature. On top of that, the engine has an excellent reputation: it's light, strong, likes to rev, and has the right characteristics for turbo preparation, thanks to good control of pressure and temperature rise.
A competition-ready Alfa Romeo Turbo Evoluzione
Prototech boasts a mechanical package built around a 16-valve autodelta cylinder head, complemented by exhaustive optimization work. The engine is based on an Alfa Romeo 2.0L, reinforced and extensively modified. Prototech teams overhauled and reinforced the ducts, custom-machined the Evoluzione camshaft supports, and carried out fine calibration on the engine dyno.
The supercharger specific to the 75 Turbo is retained, but used in a racing definition. The figures announced by the workshop match the ambition: 315 hp for the optimized 2.0L 16V version, and up to 350 hp and 400 Nm of torque in the "Group A / Evo" configuration. Enough to place this 75 among the most serious modern interpretations of the golden era of supercharged touring.
The transmission is entrusted to a reinforced "dog-box" type gearbox that allows almost instantaneous gear changes, without the need to use the clutch pedal developed to cope with high torque levels.
In the end, this creation ticks several rare boxes: the use of an Autodelta 16V engine, top-level engine preparation validated on the dyno, and a development philosophy focused on pure performance. While it can't claim the historical authenticity of a genuine vintage Groupe A, it does represent one of the most successful contemporary interpretations of the 75 Turbo.
English 
French 
Italian 
Spanish 
Portuguese 
German 
Japanese 
Turkish 
Dutch