Exhaust Cutouts

Want to switch between a quiet exhaust and an open, powerful sound at the push of a button? With a cutout – a valve typically fitted before the muffler – the exhaust gas can exit earlier. This category is for you if you want to tailor the sound and flow of your project.

How exhaust cutouts work

A cutout gives the exhaust pipe an extra outlet, so the gas can leave the system before it reaches the muffler. When closed, the car typically sounds as before. When open, the sound gets louder and back pressure can drop – how much depends on placement, pipe diameter and the rest of the exhaust system. Among the cutout kits you will find pipe solutions for specific vehicles, e.g. QTP Aggressor Cutout Pipes for the Ford F-150 Raptor and Ram 1500.

How to choose a cutout

• Pipe diameter: the valve must match your pipe; e.g. QTP QTEC valves are available in 2.5 and 3.5 inches.
• Operation: electric valves can be controlled from the cabin, while manual ones are typically adjusted at the car. See cutout controls.
• Installation: bolt-on solutions typically require no welding, while others must be welded into the pipe.
• Space: check ground clearance and the distance to wiring, fuel lines and heat-sensitive parts.
• Single or pair: on a dual exhaust with e.g. H-pipes or X-pipes, two valves can give an even sound on both sides.

Installation, maintenance and inspection

Use suitable clamps or flanges so the joint stays tight and does not cause exhaust leaks. Soot and corrosion can cause a valve to seize, so open and close it regularly, and check connectors and wiring on electric models. Whether the car can pass inspection with a cutout depends on the product and the car, and approval must be checked for the specific part number. Brands in this category include Granatelli Motor Sports, QTP, Akrapovic, Stainless Bros and Magnaflow.

Frequently asked questions

Can I drive on public roads with the cutout open?

It depends on the product, the car and the applicable noise limits. An open cutout typically produces more noise, and approval must be checked for the specific part number. On track days, the track's own noise rules apply.

What is the difference between an electric and a manual cutout?

An electric cutout is opened and closed by a motor via a switch or controller, often while you drive. A manual cutout is typically adjusted at the car and has a simpler design.

Does a cutout add power?

It can reduce back pressure, but the gain depends on the engine, pipe routing and tuning. On some cars the difference is noticed mostly as sound, and the engine management may need adjustment.

What size cutout should I choose?

Choose a diameter that matches the pipe the valve will be fitted to, e.g. 2.5 or 3.5 inches. Also check that there is room for the valve body and any motor under the car.