Praxis Fab is proud to announce the first external wastegate kit for the Cummins platform.

This kit is the T4 1-Piece Stainless Steel Manifold, FIS 45mm Wastegate, Hood exit stack and manual controller with fittings and lines.

What does a wastegate do and why do you need one?

When you decide to run a mid-frame turbo like a S400, you have many AR options for turbine housings i.e.. .90, 1.0, 1.1

A "tighter" housing like a .90 AR will reduce lag down low, get things going much quicker but will be restrictive on the big end (wide open) which will limit power and increase EGT's. 

A "looser" housing such as a 1.1 or 1.25 will allow your engine to produce much more power on the big end but you will experience a noticeable amount of turbo lag on the low end. You will experience, turbo lag, low power and much more smoke down low.

Adding an external or even a turbo with an internal will give you an adjustable turbine housing in a way. You can run a .90 AR housing that will give you great drivability and the low end power you desire but once the turbo is spooled and on its way to the moon the wastegate will open allowing a portion of the exhaust gases to bypass the restrictive turbine housing. Doing this will allow the engine to breathe while producing more airflow from the compressor side greatly increasing power and decreasing high back pressure and high EGT's.