Within the novel chassis sat Renault's, by now venerable, "Renault Gordini EF1" turbocharged 1.5-litre V6 engine. The unit had first been introduced with the Renault RS01 in , and was the first turbocharged engine ever to win a Formula One Grand Prix. Over the years the engine had been uprated and subtly redesigned, and the twin-turbo (one per cylinder bank) evolution within the RE40 produced a claimed . However, the turbochargers themselves were to prove the RE40's weakness in 1983, and on numerous occasions turbo troubles ended Prost or Cheever's race. Alain Prost later recalled that ""that year there was a good turbo to have and a bad one. We had the bad one"".