Highlights in this issue include a dossier on the AVL RACETECH hydrogen ICE and our challenge of feature investigates Dirt Late Model. We have a retro feature covering the Formula Opel/Vauxhall I4 and a show report from PMWE 2023. Our focus articles cover vibration analysis, turbos and superchargers, along with musings from Ian Bamsey over the importance of thorough documentation of race engines plus much more…