The BMW M50 is a straight-6 DOHC petrol engine which was produced from 1990 to 1996. It was released in the E34 520i and 525i, to replace the M20 engine. In September 1992, the M50 was upgraded to the M50TU ("technical update"), which was BMW's first engine to use variable valve timing. Called single VANOS by BMW, the system adjusted the phasing of the intake camshaft. The M50 began to be phased out following the introduction of the M52 engine in 1994. The E36 M3 is powered by the engine series, which is a high output version of the M50.