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5.9L Cummins Turbocharger Silencer Ring

5.9L Cummins Turbo Silencer Ring Removal Information

Don't over complicate the silencer ring on many Holset turbo models found on Cummins turbodiesels; it's a noise reduction device, not a power inhibitor. It is common to remove the ring to increase the [harmonious] sound of the turbocharger. If the silencer ring is removed but the factory airbox and air filter system is left intact, you're unlikely to notice much of a sound difference under ordinary conditions. However, replacing the factory airbox with an aftermarket system and removing the turbo silencer ring allows the turbocharger to produce the prominent, distinctly characteristic sound as it builds boost and an aggressive hiss as it spools down.

There has yet to be any proof substantiated by dynamometer reports that support any claim that removing the turbocharger silencer ring yields any quantifiable gains in engine or turbocharger performance. This modification will not increase peak boost, reduce turbo lag, or have any effect on exhaust gas temperature (EGT). This modification is to be carried out strictly in the pursuit of audible pleasure, and if you enjoy the sound of your Cummins turbodiesel than you'll likely be pleased with the results.

The silencer ring is secured in place at the mouth (inlet) of the turbocharger compressor housing by means of a large diameter retaining ring. Once the retaining ring is removed, the silencer simply lifts off the face of the compressor inlet as outlined in the following figures:

5.9L Cummins turbo silencer ring

Turbo silencer ring on a 2004 model year 5.9L Cummins ISB

How to remove turbo silencer on 5.9L Cummins

Remove the large lock/snap ring as indicated in the picture.
The silencer ring can then be slid out of the mouth of the turbocharger.

5.9L Cummins turbo with silencer ring removed

Cummins Holset turbocharger with silencer ring removed.