Tire use, energy use, finishing position all factored in for GTP winner at each WeatherTech Championship race.

Included in our preview of the the GTP and Group C cars headed to southern California for the Acura Grand Prix of Long Beach was one of three spectacular entries from Mazda Motorsports - the 1992 Mazda RX-792P IMSA GTP.Our RACER colleague, Marshall Pruett, managed to nab on-car footage from...

IMSA is taking a page from its history by changing the name of its new 2023 hybrid prototype class and cars from LMDh to GTP.IMSA’s Grand Touring Prototype formula, which debuted in 1981 and ran through 1993 (main image), at times challenged the CART IndyCar Series – tops among all...