The SRT-4 used the same basic engine block as the naturally aspirated 2003+ 2.4L and was different from the years previously used in the naturally aspirated Chrysler 2.4L mid-size cars such as the PT Cruiser and four-door Stratus. The turbocharger was a reverse rotation TD04LR-16Gk with a 6 cm2 (0.93 sq in) turbine inlet. Tight packaging forced some creative thinking on the turbocharger. The TD04 compressor has a compressor bypass valve built right into the compressor housing. The exhaust manifold and turbine housing were cast in one piece by Mitsubishi from high-nickel Ni-Resist steel.