Upower 4" Inlet Diesel Exhaust Muffler (Straight-Through Stainless Steel) XS2772
Product description
What this muffler is for
If you’re working on a diesel exhaust system and want a resonator-style muffler that’s built to handle the long haul, this Upower 4" inlet diesel exhaust muffler (model XS2772) is designed around a straight-through flow path. On paper, that means it aims to smooth exhaust sound and internal resonance without intentionally choking flow.
It’s also the kind of part you buy when you’re not just trying to “add a muffler,” but trying to finish an exhaust section with a welded-in component that matches the rest of the piping. In other words: if your setup is built around 4-inch exhaust pipe and you can weld the joints cleanly, this is meant to drop into that plan.
The essentials (how it’s built and what it does)
This muffler uses stainless steel construction and a 100% welded design, which is a big deal for people who expect to keep exhaust parts exposed to heat and moisture. It’s not described as a bolt-on clamp muffler, so the expectation here is a more permanent install where welding is part of the process.
Inside, it uses CRF (Continuous Roving Fiberglass) technology to absorb unwanted interior resonance. That’s the core of why you’d pick a resonator/muffler like this: it’s meant to reduce harshness or vibration in the sound profile, rather than simply redirecting exhaust through restrictive chambers.
And because it’s straight-through, it’s positioned as a design that does not restrict exhaust flow. That matters if you care about maintaining exhaust velocity performance—though real-world results can vary depending on your full exhaust layout.
Size and fit details you should verify first
This is where most “muffler fits / doesn’t fit” problems happen, so don’t skip the numbers. The product listing specifies:
- Inlet diameter: 4" inner diameter
- Outlet diameter: 4" inner diameter
- Overall length: 30"
- Body length: 24"
- Body type: 7" round
It also notes a flexible “both ends can be inlet” style, meaning there’s no inlet vs. outlet difference. Practically, that helps if you’re routing your exhaust where one end lands easier during mock-up.
Worth considering if your system uses 4-inch diesel exhaust piping and you’re planning a welded connection. It’s not a fit-first purchase for people running different pipe diameters.
What stands out in everyday use
Where it shines
The stainless steel + welded construction combo is the main reliability angle. Over time, exhaust components live a tough life, and a fully welded design tends to be chosen when you want fewer loose points and fewer things that can fail under thermal cycling.
The straight-through design is also a clear theme: it’s aiming to keep flow moving rather than creating a restrictive labyrinth. If your goal is more about sound/resonance control than aggressive backpressure increase, this aligns with that approach.
The limitation to keep in mind
The description doesn’t spell out any exact sound reduction numbers or performance gains, so if you’re chasing a very specific noise target (for example, to meet a strict inspection standard), you may want to manage expectations. Also, because it relies on a 4-inch matched setup, it may not be the best match for mixed-diameter exhaust work.
Is it worth it?
A solid pick if you’re building or upgrading a diesel exhaust section around 4" piping and you want a stainless steel, fully welded, straight-through resonator/muffler approach with CRF interior resonance absorption.
You may want to skip it if your system isn’t truly 4-inch all the way through, or if your install requires a non-weld method (the listing emphasizes welded construction, and it doesn’t describe a clamp-ready setup). It might not suit you if you’re trying to solve a very specific, quantified problem like a guaranteed dB drop—because the listing focuses on design and materials rather than measured outcomes.
Quick FAQ
Common buying questions
Does it reduce exhaust resonance? The muffler uses CRF (Continuous Roving Fiberglass) technology intended to absorb unwanted interior resonance.
Is it a restrictive muffler? The design is described as straight-through and does not restrict exhaust flow by its layout.
What pipe size does it fit? It’s specified for 4" inner diameter inlet and outlet, with universal fit to 4-inch exhaust pipe when you can weld the joints seamlessly.
Do I need an inlet/outlet side? The listing states both ends can be inlet, so there’s no inlet/outlet difference.
What’s included
You get 1x 4" muffler in the package.