Rear Valved Exhaust Box

Stay Legal. Stay Loud. Stay in Control.

UK MOT regulations now require a rear exhaust box to pass inspection.
But if you love the thrill of a performance exhaust, you don’t have to settle for a quiet, restrictive setup.
Our Rear Valved Exhaust Box gives you the best of both worlds—compliance when you need it and head-turning sound when you want it.

What Is a Rear Valved Exhaust Box?

A rear valved exhaust box is a specially engineered system that allows you to control your exhaust sound on demand.
With the push of a button or flick of a switch, you can instantly choose between:

  • Quiet Mode – Diverts gases through a silenced route for MOT compliance, neighbourhood friendliness, and everyday driving.

  • Sport Mode – Opens the valve to let gases flow freely for a deep, aggressive exhaust note and maximum performance.

It’s essentially like having two exhaust systems in one, giving you flexibility without compromise.

Why Choose a Valved System?

  • ✅ MOT Compliant – Meets current MOT rear box regulations.

  • ✅ Performance Ready – Maintains free-flowing exhaust performance.

  • ✅ Custom Sound – Go from refined to roaring in seconds.

  • ✅ Proven Technology – Similar systems are used by Ferrari, Porsche, and other high-end performance brands.

Our Installation

At MIJ Exhaust, we specialise in building and fitting custom exhaust systems to suit your vehicle.

  • We wire the switch to your cigarette lighter slot for a clean, functional setup.

  • If you’d like a more advanced or hidden wiring installation, we can recommend a vehicle electrical engineer for a fully bespoke finish.

Why MIJ Exhaust?

  • Over 30 years of experience in custom stainless steel exhaust fabrication.

  • Lifetime guarantee on all custom-built systems.

  • Options to adjust sound levels—from subtle to full sport—during installation.

Get Your Personalised Quote

Ready to transform your driving experience?
Simply fill out the quote form for your personalised quote or call us on 01922 645646!