Series teams are customers by pay lease system. Ilmor is the option specification engine supplier of engines for the ARCA Menards Series and NASCAR Camping World Truck Series. Truck Series teams are allowed to use the option crate engine based on the LSX, and many teams have switched to the option engine. Ilmor was heavily criticized when four of its NT1 engines failed during the 2019 World of Westgate 200 at Las Vegas Motor Speedway, effectively eliminating ThorSport Racing drivers Grant Enfinger and Johnny Sauter from the playoffs. Matt Crafton also experienced an engine failure during the race, but survived the playoffs due to his points standings. The manufacturer took responsibility for the engines that suffered from severe detonation due to the combination of the high engine load condition combined with the extreme weather conditions in Las Vegas. Despite Ilmor's announcement, NASCAR denied ThorSport's request to reinstate Enfinger and Sauter into the playoffs. In 2021 Ilmor partnered with Edelbrock to supply the 396 engine, which is primarily used in ARCA, for the Superstar Racing Experience. Mercedes-Benz in Formula One Back in F1, for 1995 Mercedes had set its sights on higher goals and went looking for an engine supply deal with a more competitive team as Ilmor elected to reposition its Formula One programme from engine supplier to trusted engine builder and assembler partner for Mercedes-Benz. Sauber had the opportunity to become a customer team, but team principal Peter Sauber opted to sign a deal with Ford instead. From then on Ilmor built the Mercedes-Benz engines exclusively for McLaren after Ilmor repositioned its Formula One involvement from independent engine manufacturer to trusted engine builder and assembler to Mercedes-Benz High Performance Engines. The Ilmor engines went on to be hugely successful with McLaren, scoring several podiums in both 1995 and 1996, leading to three wins in 1997 and back to back drivers championship in 1998 and 1999, as well as the constructor's championship in 1998. Although they did not win another championship until 2008 the Ilmor-Mercedes engines won several races. In 2001 Paul Morgan was killed while landing one of his vintage airplanes, a Hawker Sea Fury at Sywell Aerodrome, Northamptonshire. In 2002 DaimlerChrysler increased its share to 55% and renamed the company Mercedes-Ilmor. In 2005 DaimlerChrysler became the sole owner of Ilmor and renamed the company Mercedes-Benz High Performance Engines Ltd. Ilmor Engineering, Inc. – expansion to the U.S. Ilmor