Alfa Romeo - World Champion
In the early Twenties the public at races was wildly enthusiastic, with huge crowds attending the GP, and as a result this had a substantial effect on sales. So Vittorio Jano left Fiat and joined Alfa Romeo in October 1923. He was personally appointed by Nicola Romeo to design the P2. "Listen, I am not expecting you to make a car which will beat all others, but I'd like one which will make us look good, so that we can make an identity card for this factory, then later, when it has a name, we'll make the car."
Jano's first move was to make design a two-litre inline straight eight cylinder engine, with a double crankcase, fixed steel heads and a gear-driven twin-cam valvetrain gear. The obvious superiority of supercharged engines, of which Jano's Fiat had been one of the first, encouraged the designer to fit a Roots supercharger to the P2, now fitted equipped with an ante-litteram intercooler to stop prevent the petrol of the day catching fire, a finned "lung", fitted to the bottom of the car which that was able to reduce the temperature by a further 7-8°C. The power output was 140 hp at 5500 rpm. The chassis was much more traditional, consisting of a ladder-type layoutwith longerons and cross-members, while the bodywork, with two staggered seats, could be fitted with an aerodynamic tail section or a trunk with two spare wheels. The overall weight of the car was 750 kg.
The first car example was assembled on the 2nd of June 1924 and was immediately tested at the Portello by Campari and Ascari, after which it was painted and taken to Monza. A few days later, the car had made its debut in the Circuito di Cremona, won by Ascari at an average speed of 158 kph. The victory at Lyons in the European GP in 1924 was the beginning of a long period when the car was virtually unbeatable, culminating at the end of 1925 with winning the first World Championship for Grand Prix cars. The P2 was relegated to minor races as a result of changes to the rules in 1926 that limited engine displacement to 1.5 litres. The P2 car started to compete at the top again returned to competition during the 1930 season when the manager Prospero Gianferrari bought back three of the cars examples and thoroughly redeveloped them, employing some of the new technical innovations used on the 6C 1750. The result was an extremely powerful but ill-tempered car. It was so bad that Campari, after a few test laps refused to drive it as he was exhausted.
The ageing P2's greatest success came in the Targa Florio in 1930, won by Varzi, despite the fact that a bracket supporting the spare wheel (fixed to the petrol tank) caused a leak and the beginnings of a fire which was extinguished by the co-driver during the race using the seat cushions. The glorious P2 took part in a race for the last time in Brno on the 28th of September 1930. It then became part of the legend.