Mercedes-Benz OM617 HE221 (T25) Installation Kit for Holset Turbos

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  • Regular price $299.00

Mounting a Holset HE221 or other T25 frame turbo to your om617 can be a total pain in the ass but it doesn't have to be!  The BenzForce HE221 Installation Kit for the om617 takes the headache out of the physical connections.  All that is needed is a 4AN feed line and a 12AN drain hose. Please note that this kit does not connect directly to the intake manifold - there is an offset.  The main intent is to be used in injunction with our intake manifold adapter to route your compressed air through an intercooler.

Here is what is included: 

  • BenzForce HE221 Wastegate Bracket Kit (with gasket and nuts). This bracket was engineered to have the proper wastegate preload. Instructions are below
  • BenzForce 79mm exhaust v-band to 3" tube adapter for Holset turbos (adapter + clamp)
  • BenzForce 12AN Drain Tube kit (screws, gasket, and drain)
  • BenzForce HE221 (56mm) compressor v-band to coupler adapter (with clamp and o-ring)
  • BenzForce om617 - 12AN to oil pan turbo drain fitting (with grommet)
  • BenzForce T3 to T25 Turbo Adapter kit designed specifically for the om617 (with bolts, nuts, and gaskets).  This adapter uses bolts to mount to the manifold and studs on the turbo side which is difficult to find in the aftermarket
  • DCEC T25 manifold gaskets
  • HE221 Turbine Flange Kit - 4 bolt (with bolts and gasket)
  • 4AN M10 feed fitting (the om617 oil pressure exceeds Holset specifications so we recommend an oil pressure regulator)
  • Turbo not included


Wastegate Installation Instructions:

  • Remove the wastegate hose
  • Remove the wastegate actuator. After pulling the internal pin allowing the compressor housing to rotate independently, just remove to cotter pin on the wastegate (or a C-clip on the 5.5 cm2 models) and the two bolts holding the wastegate on the turbo.  This will allow you to completely remove the wastegate.
  • Mount the bracket.  Remove the turbo from the T25 flange.  Place, or replace, a new T25 gasket on the flange.  Then install the wastegate bracket, followed by another T25 gasket.
  • Install the turbo
  • Reinstall the actuator.  Rotate the actuator 180 degrees from its original position.   Put the end over the pin on the turbine housing and install the original cotter pin or c-clip.  Then pull the actuator and insert the original two bolts through the bracket and through the stock actuator bracket.  The actuator comes pre-loaded from the factory so pulling the actuator should put the same amount of tension on the actuator as the original configuration.  Use the included copper exhaust nuts to secure the actuator to the BenzForce bracket.
  • Install boost hose.  Depending on how the turbo is clocked, you can either reuse the existing boost hose or you may require a new one.  Regardless, reinstall the hose so the actuator will see boost from the compressor housing.

Note that the HE221 has clocking pins inside the turbo.  Both the compressor and turbine housings pins will need to be removed in order to rotate the core