British and European Car Spotters Guide - 1924

In the early 1920s, the Italian automotive engineer, Giuseppe Merosi, designed the Alfa Romeo RL. This was not his first design for Alfa; his history with the company dates back to the early 1910s when he designed the A.L.F.A. 24 hp. During the mid-1910s he designed a DOHC four-cylinder engine that had 16-valves and displaced 4.5-liters. The Alfa Romeo RL was produced from 1922 through 1927. It had a displacement size of 2.9-liters from its six-cylinder engine, that would continue to increase in size throughout the years, culminating with a 3.6-liter size and around 125 horsepower. There were four versions of the RL created, the Normale, Turismo, Sport, and RLTF (for Targa Florio). The RLTF was a purpose-built, racing versions that was stripped of non-essential items, given sleek designs, and weighed about half of the other versions. The engine was finely tuned and given seven main bearings and double carburetors. It was used in competition by such legendary drivers as Ugo Sivocci, Enzo Ferrari, Antonio Ascari, and Giulio Masetti. On example driven by Sivocci won the 1923 Targa Florio race. The RL featured a pushrod OHV 6-cylinder engine mated to a four-speed, suspended by semi-elliptic springs, and placed in a ladder frame.

A 1924 Bianchi Type 18, with bodywork built by Fountain of Great Britain.

Designated the 4A 106, the updated Tropfenwagen had a conventional four-cylinder-in-line engine of 2614cc developing 50 bhp at 2400. Overall design was otherwise little changed apart from a longer wheelbase to accommodate the new power unit (which gave the incidental benefit of increasing passenger capacity from 4/5 to 6/7. Top speed was around 75 mph, but it was said that the increase in wheelbase had upset the roadholding. Sales continued to be minimal, and in 1925 Rumpler modified the design to give somewhat more generally acceptable lines, with 'proper' mudguards and running boards.