At the second round of the 2023 Formula 4 United States Championship (F4 U.S.) in mid-May, Ligier Automotive North America and championship organiser Parella Motorsports Holdings introduced the Ligier JS F422. This second-generation single seater will replace, as of next season, the Ligier JS F4, which has been since 2016 the exclusive chassis of the F4 U.S. Championship.
The JS F422 has been designed to take a number of F4 engines. In the 2024 F4 U.S. series it will be powered by a new engine known as the Ligier Storm V4 by SuperHP. This is a 90-degree bank angle, 1.65 litre pushrod V4 having two valves per cylinder. In F4 U.S. configuration, it is naturally aspirated and produces power in the region of 190bhp. It’s configuration echoes that of the Motus V4 which was profiled in Race Engine Technology magazine back in 2010 in its original guise.
As our 2010 article explained, the Motus V4 was originally designed by Katech. It was in some respects a scaled version of a GM LS V8, as its bank angle and its pushrod, two valve configuration would suggest. However, Katech, which prepared the Chevrolet LS7R Le Mans GT engine, cited a number of influences for this clean sheet design including the Chevrolet LS7R, the LS7 road car engine that powered the Corvette Z06 and the naturally aspirated, direct-injection 3.6 litre Cadillac V6 road car engine.
As we explained this V4 was perceived as a potential racecar engine across a number of applications. Since 2010, it has been further developed by Mast Motorsports. In 2020 the rights to the engine were acquired by a company known as SuperHP, which is owned by one of the members of Performance Assembly Solutions, a well-established company renowned for building engines under contract for Ford, GM, and others.
SuperHP and Ligier Automotive North America have collaborated to further develop the V4 to maximise its potential for racecar applications. This includes many changes including a dry sump with a lower crankcase that incorporates the main bearing caps. Compared to the I4 unit it replaces in F4 U.S., its’ vee configuration and lower weight have allowed Ligier to produce a longer and safer car that is nevertheless lighter than the current machine with this engine installed.