CST4 Turbocharger

The CorkSport CST4 is a high-performance turbocharger upgrade engineered as a direct replacement for the factory K04 turbo in Mazdaspeed 3 and Mazdaspeed 6 models. It utilizes a custom MHI 18G billet compressor wheel, capable of supporting a 50 lbs/min flow rate and boost pressures up to 30psi, paired with an MHI TD05H high-flow turbine wheel featuring a 9-blade design for improved response and spool. This turbocharger is designed for a range of builds, from mildly modified vehicles with stock fueling to more extensively built engines with auxiliary fueling, supporting power outputs from 250-450whp. It maintains OEM fitment for the compressor inlet and turbine sides, ensuring compatibility with most aftermarket intakes and the factory downpipe and exhaust manifold. Buyers can choose between two wastegate configurations: an Internal Wastegate (IWG) setup with a 0.66 A/R turbine housing for simpler installation, or an External Wastegate (EWG) setup with a 0.82 A/R turbine housing designed for 44mm external wastegates. The EWG option includes a V-band clamp and elbow pipe. All necessary hardware, including gaskets and studs, is provided for a complete installation. A free CorkSport 3.5 bar MAP sensor is also included for accurate boost pressure readings up to 37psi.