CRT's Ultra series is one of the most powerful S400 series turbochargers available on the market today. Dyno and track proven over and over again. The Ultra series comes standard with our V3 compact race cover, our blueprinted hydrodynamic bearing system with heavy duty thrust system and the latest XR compressor wheel aerodynamics. The Ultra series is also available with our proven ball bearing system as an upgrade. Custom sizes and configurations available.