Granatelli 4" Electric Exhaust Cutout Kit, Mild Steel Slip-Fit – 303540

Granatelli Motor Sports 4.0″ Electronic Exhaust Cutout Kit – Aluminized Mild Steel

SKU: 303540

Transform Your Ride with Dual-Mode Sound & Performance

Switch effortlessly between refined street-level rumble and wild, track-ready roar. The Granatelli 4.0″ electronic exhaust cutout offers full control over your exhaust tone and performance—instantly—right from inside the cabin.

4 Inch Electronic Exhaust Cutout Kit Key Features

• Massive 4.0″ ID – delivers unrestricted exhaust flow and reduces backpressure for big power gains
• CNC 6061‑T6 aluminum body – built to handle extreme heat and abuse
• Stainless steel butterfly valve & shafts – long-lasting and corrosion-resistant
• Smart‑Chip motor with one-touch rocker switch – press once to fully open or close; no holding required
• High-torque DC motor with carbon‑steel gears – ensures reliable, complete valve actuation
• 360° adjustable polished stainless turndown (45° angle) – allows optimal positioning in any setup
• Complete kit – includes gaskets, hardware, wiring harness, and switch for seamless installation

Ideal Applications

• High-output turbocharged or supercharged engines
• Large displacement race and street builds
• Drag racers, show cars, and hot rods demand ultimate flow and sound flexibility

Why Choose the 4.0″ Cutout Kit?

• Instant power boost: Reduced exhaust restrictions help unlock horsepower, especially under load or boost
• Dual personality: Keep it quiet for daily driving, then unleash full performance on demand
• Durable design: Built to withstand heat, vibration, and frequent use with precision-grade materials
• Universal fitment: Slip-fit aluminized mild steel works with nearly any 4″ exhaust setup—no custom work needed

What’s in the Box

• 4.0″ electronic exhaust cutout valve
• Polished 45° stainless turndown
• Slip-fit and band clamps
• Wiring harness and one-touch rocker switch
• Installation hardware and gaskets

Final Word

Ready to rule the streets, the strip, and the garage? The Granatelli 4.0″ Electronic Exhaust Cutout Kit delivers unmatched control over sound, flow, and performance—wherever your driving takes you. Embrace the roar or keep it discreet—it’s your ride, your rules.

Sizing & Fitment

Measure the outside diameter of your exhaust pipe at the mounting point. If it measures 4", this kit is the right match. Running a true dual exhaust? Use one cutout per side, or choose the dual 303540D kit. Want a permanent, leak-free install? See the 307540 weld-in version. Daily driver in a wet or salted-road climate? Consider the stainless steel 302540.

Where to Mount It

Mount the cutout at least 18 to 24 inches after the catalytic converters, and away from any O2 sensor. Aim the turndown toward the rocker panel, away from fuel and brake lines. For the best sound, mount it after the X-pipe or H-pipe.

Legal Note

Many states, including California, prohibit exhaust cutouts on vehicles driven on public roads. Keep the cutout closed on the street and open it only at sanctioned off-highway events. Never install a cutout upstream of a catalytic converter.

Frequently Asked Questions

Do I have to hold the switch?
No. The Smart-Chip one-touch rocker completes the valve's travel with one tap.

Can I install it myself?
Yes. This kit clamps onto the pipe, so most installs need only basic hand tools and a way to cut the pipe.

What's the warranty?
90 days, with optional 1-, 2- or 3-year extended coverage available at checkout.

Will it add horsepower?
Opening the cutout reduces backpressure. Gains depend on your engine, headers and tune.

New to cutouts? Read our 4 Inch Exhaust Cutout Guide for choosing the right size and type, mounting and state laws.