CST4 Turbocharger w/ MHI 18G Billet Compressor

The CorkSport CST4 Turbo Upgrade is engineered as a direct replacement for the stock K04 turbocharger, offering an easy path to significant power gains for your Mazdaspeed 3 or Mazdaspeed 6. The CST4 is capable of supporting 250-450whp, making it suitable for mildly modified vehicles with stock fueling up to budget-built engines with full bolt-ons and auxiliary fueling. At its core, the CST4 features a custom MHI 18G billet compressor wheel, enabling efficient flow rates of 50 lbs/min and boost pressures up to 30psi, providing higher boost thresholds and improved efficiency over cast wheels. Complementing this is an MHI TD05H high-flow, 9-blade turbine wheel, reducing rotational mass for quicker response and spool. The turbo utilizes a high-performance MHI Journal bearing CHRA for increased cooling capacity and proven reliability, featuring upgraded journal bearings and a 360-degree high-performance thrust bearing. A custom billet wastegate actuator allows for operation in bleed mode for the OE EBS or interrupt mode with an electronic boost controller for enhanced control. All necessary hardware, including gaskets and studs, is included for a straightforward installation, which is estimated to take 5 hours. Buyers have the choice between an Internal Wastegate (IWG) setup with a 0.66 A/R turbine housing or an External Wastegate (EWG) setup with a 0.82 A/R turbine housing designed for 44mm EWGs. The EWG option includes a V-band clamp and elbow pipe, but the external wastegate itself and a screamer pipe are not included. **Important Considerations:** An upgraded High-Pressure Fuel Pump (HPFP) and a COBB Accessport with a custom tune are required for this product. Auxiliary fueling is also necessary for peak power operation. Note that some aftermarket downpipes may not clear the EWG elbow included with the CorkSport EWG Turbocharger. The EWG variant is specifically designed for Tial 44mm or equivalent external wastegates, which are sold separately.