Product Description
MBRP M91031 is a universal, high-flow diesel muffler that replaces any 30" overall length muffler. Built from T409 stainless (Armor Plus), it features a 4" single inlet / 4" single outlet, a 24" body, ~6" case diameter, and classic MBRP tone for strong flow without excessive drone.
- Material: T409 Stainless Steel (Armor Plus)
- Inlet/Outlet: 4" ID / 4" ID (single in / single out)
- Body Length: 24"
- Overall Length: 30"
- Case Diameter: ~6"
- UPC: 882963100764
Fitment
Universal 4" exhaust sections across popular diesel pickups and custom builds. Direct replacement for any 30" overall length muffler with 4" connections. Verify available straight section length and hanger position before install. Clamp-in or weld-in.
Cross-Reference / Alternatives (MBRP Only)
- MBRP M1004S – Quiet Tone, T409, 4" in/out, 24" body, 30" OAL.
- MBRP M1004A – Quiet Tone, Aluminized, 4" in/out, 24" body, 30" OAL.
- MBRP M1031 – Armor Pro (T304), 4" in/out, 24" body, 30" OAL.
- MBRP GP015 – 30" High-Flow 4" Muffler.
- MBRP M2050S – 5" in/out muffler (31" OAL), T409.
- MBRP R1009 – 4" resonator, T304 (tone control).
- MBRP MDS30 – 30" muffler bypass (straight pipe), T304.
What’s Included
(1) MBRP M91031 muffler. Clamps/hangers sold separately.
Helpful Notes
- Confirm 30" overall length section and 4" tube compatibility before ordering.
- T409 is highly durable; surface discoloration is normal in harsh climates.
FAQ
Will this fit my truck?
It’s universal for 4" exhaust runs and replaces a 30" overall muffler. Measure the straight section available and ensure 4" connections.
How loud is M91031 compared to Quiet Tone?
M91031 has a classic MBRP performance note. M1004S/M1004A run quieter with additional packing.
What are the exact dimensions?
4" inlet/outlet, 24" body, 30" overall, ~6" case diameter (universal).
Is there a stainless upgrade?
Yes—see M1031 (T304). For 5", consider M2050S.
Specs verified against the manufacturer and CPP listing. UPC confirmed via multiple distributor databases.
