Adaption of the HE221 to an om605

We have had several people ask about installing an HE221 into an om605.  I would like to thank @dorschtaler__performance for the notes below that point out what you can expect.  The loss of space on the om605 vs the om606 makes things a bit more challenging when trying to find room for the oil drain.  Here are JP’s notes on his install:

  • Need a 16M to 4AN block fitting: Since JP started this installation, BenzForce has released this fitting:
  • 135° -12 fitting on the BenzForce T3 12AN drain
  • The om606 12AN BenzForce fitting needed to be angled and shortened to work.  JP opted to fab his own and a straight fitting used to meet the turbo drain
  • The air intake took some finessing from 70mm to 76mm (3") and for charge piping, he used a silicone step-down directly to the stock piping.
  • In a w202, the compressor housing contacts the header heat shield bolt with the model HE221 that JP used.  His HE221 was a different model than those stocked by BenzForce.  

In case some readers are leary of dealing with AN hose constructions, BenzForce also has hose barbs which provide an easier installation alternative.

Here are some relevant products:

  • om617 HE221 (T25) Installation Kit for Holset Turbos - 12AN:
  • Exhaust adapter:
  • Compressor adapter:
  • 4AN fitting:
  • Manifold adapter:
  • Wastegate adapter:
  • T25 Oil drain (barb):
  • T25 Oil drain (12AN):
  • M16 to 4AN fitting:


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