An investigation has found that the high-performance Porsche that "Fast & Furious" actor Paul Walker was riding in was travelling up to 150kmh when it crashed and burst into flames, killing him and the driver, Los Angeles Times reported Tuesday.

The rate of speed was determined using surveillance videos and electronic data retrieved from the car's computers with the help of the carmaker, according to the investigation by the LA County Sheriff's Department.

The 2005 Porsche Carrera GT, driven by Walker's friend, Roger Rodas, was travelling about twice the 70kmh limit when it crashed November 30 on a curvy road in a Santa Clarita business park, investigators found.

They have also found that a pair of nine-year-old tyres contributed to the crash. There was no evidence of any car system failures, such as the brakes, according to the report.

Walker and Rodas were killed almost instantly, succumbing to multiple traumatic injuries and a fire that quickly consumed the car.

Walker died of "severe blunt head, neck and chest trauma", sustaining a broken arm, wrist, jaw and ribs, according to the coroner's report. The fire burned his body beyond recognition.

Rodas suffered similar injuries and a fractured skull.