MHI External Wastegate O2 Housing


An MHI O2 housing made for externally wastegated setups that are also looking for some increased exhaust flow. We take a more involved approach to make the most out of the small space between the factory flanges while also offering options for all of the various 1g/2g/fwd/awd DSM and Early Evo O2 housings so you can still utilize your existing 2-bolt downpipe.

Flanged for an external 38mm MVS or 44mm MVR wastegate (please specify) and for a 1g/2g/GVR4/Evo 1,2, or 3/Colt etc (please specify).

-O2 housing flanged for your choice of wastegate, O2 bung, and outlet flange style


We will be offering a recirculated option, and a version for internally wastegated setups soon as well. Once we build some we will have a better idea on cost/price.

*As of Jan 23 2024, a batch of flanges have been ordered with a lead time of 3-4 weeks to cut yet, so placed orders won’t be able to started until then.

Out of stock


  • Direct bolt-on and exact fit for 1g/2g/FWD/AWD DSM and Evo 1-3, built to be compatible with downpipes meant for your factory O2 housing
  • Tight but well executed 2.5″ bend that isn’t sharply angled off the flanges, and maintains a consistent CSA throughout
  • Exact wastegate position that we’ve found to clear any configuration, giving the most radiator clearance possible with a larger MVR wastegate while clearing a 2g/Evo1-3 alternator stud throughout the alternator’s entire adjustment range.
  • Outlet flange threaded for M12x1.25 factory studs, with outlet angle and bolt spacing tailored to various 1g/2g DSM and Evo 1,2,3 options
  • Factory O2 bung or wideband (heatsink) O2 bung available (only room for one or the other)
  • Most common with 38mm MVS or 44mm MVR wastegate provision off the O2/turbine housing, with other comparable wastegate flange options available if specified.
  • 100% 304 stainless steel, 100% backpurged.

Price is without dumptube. With dumptube is $460 total plus shipping

We don’t have a “buy it now” feature to assure we are making you the exact product for your application and needs. By filling out this client worksheet, you can help us begin that dialogue. After receiving the completed sheet, we will review it and contact you within 1-2 business days.

MHI External Wastegate O2 Housing