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HMD Fabrications

4" Variable Muffler

4" Variable Muffler

Regular price $499.99 USD
Regular price Sale price $499.99 USD
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The HMD 4" Variable Muffler gives the driver full control over exhaust noise from inside the cab. An illuminated toggle switch wires through a heat and water-resistant harness to an electronically actuated valve. Open it up for a deep unrestricted tone. Close it down for towing, daily driving, and early starts. Precision TIG-welded from 304 stainless steel and back purged so the inside of every weld stays clean and corrosion-resistant. Simple, tough valve design built to run hard and hold up. Fits most 4" diesel exhaust setups.

Key Features

  • TIG-welded 304 stainless steel, back purged for a clean internal weld
  • Electronically actuated valve, toggle-switch controlled
  • Full open to near-silent, on demand
  • Complete ready-to-use wiring harness, includes 5A fuse
  • Heat and water-resistant harness routes from valve into the cab
  • Universal 4" OD, fits most 4" diesel exhaust setups

What's Included

  • 1x 4" Variable Muffler
  • 2x 4" OD band clamps
  • 1x Wiring harness with illuminated toggle switch and 5A fuse
  • 1x Installation guide

Specifications

  • Material: 304 stainless steel
  • Construction: Fully TIG-welded, back purged
  • Inlet / Outlet: 4" OD
  • Dimensions: 23" x 13"
  • Valve: 12V electronically actuated
  • Control: Illuminated toggle switch (included)
  • Electrical: 5A fused harness (included)
  • Finish: Polished stainless
  • Designed in: California, USA

Fitment Notes

Works with most 4" diesel exhaust setups. Installation requires cutting existing exhaust and clamping or welding into place. If you're unsure about fitment for your truck, message us before ordering.

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