Product Description
MBRP M20681 is a universal, high-flow 4" aluminized steel muffler designed for diesel and heavy-duty gas applications that use 4" exhaust. It features a straight-through, perforated-core design for flow, a 6" case diameter, and a 30" overall length—ideal for deep tone without excessive drone.
- Material: Aluminized steel (Armor Lite)
- Inlet/Outlet: 4" (center/center)
- Body Diameter: 6"
- Body Length: ~15.75"
- Overall Length: 30"
- Core Type: Straight-through, perforated
- Universal replacement for many 30" overall 4" mufflers
Fitment
Universal 4" inline muffler for trucks and custom builds using 4" exhaust tubing. Common on Dodge/Ram Cummins turbo-back and filter-back systems, as well as other diesel platforms. Verify dimensions and hanger locations for your specific setup.
Cross-Reference / Alternatives
- Quieter 4" option (aluminized, 30" OAL): MBRP M1004A Quiet Tone 4" Muffler
- Premium stainless 4" option (T304, 30" OAL): MBRP M1031 4" Muffler (T304)
- High-flow 4" alternative (30" OAL): MBRP GP015 High Flow 30" 4" Muffler
- Muffler delete (for race/off-road): MBRP GP016 30" 4" Muffler Delete
- 4" band clamp (304 SS, Torca): Diamond Eye BC400S304 4" Band Clamp
- 4" U-bolt clamp (zinc): Diamond Eye 454000 4" Saddle Clamp
- Popular 4" downpipe for Cummins builds: MBRP HX40 4" Downpipe & Clamp
Install Notes
Requires cutting/positioning in a straight section of 4" tubing. Use quality band clamps or have joints welded for best sealing. Maintain safe clearances to fuel/brake lines, wiring, and suspension components.
Warranty
MBRP Armor Lite (aluminized) components carry a limited warranty; surface discoloration and corrosion from heat/precipitation are generally excluded. See manufacturer terms.
FAQ
Will this fit my truck?It’s a universal 4" muffler. If your system uses 4" tubing and has room for a 30" overall case, it will fit. Measure first and confirm hanger/clocking needs.
How loud is the M20681 compared to stock?
It’s straight-through and generally deeper/louder than most OEM mufflers. For a quieter tone, consider the M1004A Quiet Tone.
Is aluminized steel good for winter/salt states?
Aluminized offers strong value but can corrode faster in harsh, salty climates. For maximum longevity, step up to stainless like M1031 (T304).
What clamps should I use?
We recommend a quality 4" band clamp such as BC400S304 for a clean, serviceable joint. U-bolt clamps like 454000 also work and are budget-friendly.
