D190 Riser/Exhaust Elbow

Went and bought the engine in Houston but no riser/exhaust elbow. Can buy an OEM one from Germany for $1456 delivered. That probably will not happen. I can have a stainless steel one made for $200. Big question about design. The flange end of the riser bolts to the turbo. The raw water from the heat exchanger comes in just after the turbo. This doesn't look right to a noobie like me. What prevents the raw salt water from the heat exchanger back flowing into the turbo when the engine is shut down? The stock OEM riser has the same setup.


  • Riser, SS.jpg
    Riser, SS.jpg
    268.1 KB · Views: 66
  • Riser, Original.JPG
    Riser, Original.JPG
    61.2 KB · Views: 70