Where Should You Install an Exhaust Cutout? Location Matters More Than You Think

Buying the right exhaust cutout is only part of the job.

Where you install it can make just as much difference.

Cutout location can affect:

• Exhaust flow

• Sound

• Ground clearance

• Heat exposure

• Wiring longevity

• Check-engine lights

• Installation difficulty

• How much of the exhaust system you're actually bypassing

Install the cutout in the right location and you get a clean, functional system that gives you an aggressive exhaust note and a lower-restriction exhaust path at the push of a button.

Install it in the wrong location and you can create unnecessary heat problems, clearance issues or problems with oxygen-sensor readings.

So where should a Granatelli electronic exhaust cutout actually go?

Let's break it down.

The Basic Rule: Install the Cutout After the Catalytic Converters and Oxygen Sensors

For a street-driven, emissions-equipped vehicle, one of the most important considerations is the location of the catalytic converters and oxygen sensors.

Granatelli's installation instructions state:

Never install the exhaust cutout in front of the catalytic converters.

Granatelli also recommends that the cutout should not be installed upstream of oxygen sensors.

Why?

Modern engine-management systems use oxygen sensors to monitor the exhaust and make fuel-management decisions.

Opening an exhaust path upstream of an oxygen sensor can potentially introduce outside air or alter what the sensor sees.

That can potentially cause:

• Check-engine lights

• Incorrect sensor readings

• Fuel-trim changes

• Emissions-system problems

When properly installed after the catalytic converters and oxygen sensors, Granatelli states that its exhaust cutouts generally do not require a computer reflash or expensive custom tune simply because the cutout was installed.

Learn more:

https://granatellimotorsports.com/pages/exhaust-cutouts

Don't Install an Electronic Cutout Too Close to the Headers

Heat is another major consideration.

The closer you get to the engine and headers, the higher exhaust temperatures become.

While the exhaust valve itself is designed for a demanding environment, an electronic cutout also contains an electric actuator and other components that benefit from being positioned away from extreme heat whenever possible.

Granatelli's current electronic exhaust cutout installation instructions recommend installing the electric exhaust gates:

As far away from the headers as practical and no less than approximately 18 inches from the header collectors.

That gives the exhaust gases some opportunity to cool before reaching the electronic cutout assembly.

This can help improve the long-term operating environment for the motor and control system.

Why Would You Want the Cutout Farther Forward?

There is another side to the equation.

The farther forward the cutout is located in the exhaust system, the more downstream exhaust components it may be able to bypass.

Imagine this layout:

Engine → Headers → Catalytic Converter → Cutout → Resonator → Muffler → Tailpipe

Open the cutout and you may bypass:

• Resonator

• Muffler

• Long sections of exhaust tubing

• Tailpipe

That can create a dramatic change in sound and potentially reduce downstream exhaust restriction.

Now imagine placing the cutout almost at the rear bumper:

Engine → Headers → Catalytic Converter → Resonator → Muffler → Cutout → Tailpipe

Opening the cutout there would bypass very little of the restrictive portion of the system.

You would still get a sound change, but the potential reduction in restriction could be much smaller.

The Sweet Spot

For many applications, the ideal location is:

After the catalytic converter and oxygen sensors, but before the major downstream restriction you want to bypass.

Usually that means before components such as:

• Mufflers

• Resonators

• Restrictive rear exhaust sections

while still keeping sufficient distance from extreme header heat.

There is no single location that works perfectly for every vehicle.

That's why looking underneath the car before installation is so important.

Think About What You're Trying to Bypass

Before cutting any exhaust pipe, ask:

What am I actually trying to accomplish?

If Your Goal Is Sound

You want the cutout far enough forward to bypass the components responsible for quieting the vehicle.

Usually that means positioning the cutout ahead of the mufflers and possibly the resonators.

If Your Goal Is Maximum Exhaust Flow

You want to bypass as much unnecessary downstream restriction as practical while keeping the installation safe and compliant.

If Your Goal Is Mainly Street Driving

You may prioritize:

• Ground clearance

• Heat control

• Easy wiring

• Exhaust direction

over trying to mount the cutout as far forward as physically possible.

The best installation balances all of these factors.

Ground Clearance Is Critical

Finding a location with enough physical room is just as important as choosing the correct point in the exhaust system.

Granatelli recommends positioning the system to maximize ground clearance.

Whenever practical, the cutout should not become the lowest component underneath the vehicle.

That's particularly important on:

• Lowered Camaros

• Corvettes

• Mustangs

• Pro Touring cars

• Street/strip cars

• Vehicles transported on trailers

• Cars with lowered suspension

Speed bumps are one concern.

Driveways are another.

But trailer ramps and drive-on lifts can be even worse.

A cutout that clears the road perfectly may scrape when the vehicle transitions onto a trailer.

Don't Let the Cutout Hang Below the Chassis

A good way to look at the installation is from the side of the vehicle.

Ask:

Is the cutout hanging lower than the major chassis components around it?

Granatelli's installation guidance recommends mounting the system parallel to the ground where practical and avoiding a position where the cutout hangs below the frame rail.

You want the exhaust cutout tucked up into the available space rather than becoming the first thing to contact the pavement.

This Is Exactly Why Oval Exhaust Cutouts Exist

Sometimes there simply isn't enough vertical room for a traditional round cutout.

A 3-inch round exhaust component naturally requires roughly 3 inches of vertical space.

That's a lot underneath a very low car.

Granatelli developed its 3-inch oval electronic exhaust cutout specifically for situations like this.

The Granatelli oval system is approximately:

2.25 inches tall

compared with approximately:

3 inches for traditional round tubing.

That's roughly:

0.75 inch of additional ground clearance.

On a lowered vehicle, three-quarters of an inch can make a major difference.

Learn more about Granatelli round and oval cutouts:

https://granatellimotorsports.com/pages/exhaust-cutouts

You Can Install an Oval Cutout on Round Exhaust

Another common misconception is that you need a complete oval exhaust system to run an oval cutout.

You don't.

Granatelli offers round-to-oval transitions so a traditional round exhaust can transition into the low-profile oval cutout.

This gives you the ground-clearance benefits of the oval design without rebuilding the entire exhaust system.

Watch the Granatelli Installation Video

Granatelli Motor Sports demonstrates how to install an oval exhaust cutout onto traditional round exhaust tubing:

https://www.youtube.com/watch?v=EZBb_Q33Fxs

Exhaust Direction Matters Too

Remember what happens when the cutout opens.

Hot exhaust gases are coming out underneath the vehicle.

You don't want that exhaust directed at something sensitive.

Pay attention to:

• Fuel lines

• Brake lines

• Electrical wiring

• Transmission components

• Driveshaft

• Suspension bushings

• Floor pan

• Plastic components

Granatelli systems use a 45-degree stainless-steel turndown to help direct exhaust gases away from the underside of the vehicle.

Why Granatelli Uses a 360-Degree Adjustable V-Band

This is where Granatelli's V-band design becomes useful.

The turndown doesn't have to point in only one direction.

The V-band connection allows the installer to rotate the exhaust outlet to find the best orientation before tightening everything into its final position.

That gives you more flexibility around:

The frame

Driveshaft

Transmission

Crossmember

Suspension

Floor pan

Every vehicle is different.

Being able to rotate the exhaust outlet can make a difficult installation considerably easier.

Single Exhaust vs. Dual Exhaust

Location also depends on whether the vehicle uses a single or dual exhaust system.

Single Exhaust

A single cutout can typically be installed in the main exhaust path before the muffler or other downstream restriction.

True Dual Exhaust

A true dual system may use two cutouts.

One for each bank.

That can allow both sides of the exhaust system to open together.

Granatelli offers both single and dual electronic systems specifically for these different configurations.

What About a Turbocharged Vehicle?

Turbo applications require additional thought.

The turbocharger itself is part of the exhaust system.

Exhaust energy upstream of the turbine drives the turbo.

For many turbocharged applications, a performance exhaust cutout would be located downstream of the turbocharger, allowing the exhaust exiting the turbine to take a shorter, less restrictive path.

Exact placement depends heavily on:

• Turbo location

• Downpipe configuration

• Catalytic converters

• Oxygen sensors

• Vehicle packaging

• Exhaust temperature

A custom turbo system is one of the situations where having an experienced exhaust fabricator involved can be especially valuable.

What About Supercharged or Naturally Aspirated Cars?

The same general rules apply.

You want to position the cutout:

After required emissions equipment

Away from excessive heat

Before the restriction you want to bypass

High enough for proper ground clearance

Where exhaust can be directed safely

Supercharged and high-horsepower naturally aspirated engines can move a tremendous amount of exhaust, which makes the position and size of the cutout even more important.

Slip-Fit or Weld-In?

Granatelli offers both configurations.

Slip-Fit

A slip-fit system can make installation easier because it can be incorporated into the exhaust using clamps rather than requiring the entire assembly to be permanently welded.

Granatelli has a detailed video showing a slip-fit electronic exhaust cutout installation on a truck:

https://www.youtube.com/watch?v=7oazdw4kLmE

Weld-In

A weld-in installation provides a permanent connection and can be useful on custom exhaust systems.

If you're not experienced with exhaust fabrication and welding, professional installation is recommended.

Don't Forget the Wiring

Mechanical location isn't the only consideration.

The actuator needs electrical power and the wiring must make its way into the vehicle.

Think about the wiring route before permanently installing the cutout.

Avoid routing wires directly against:

• Exhaust tubing

• Headers

• Sharp metal edges

• Moving suspension

• Driveshafts

• Other high-temperature components

A beautiful cutout installation isn't very useful if the wiring gets melted the first time the exhaust reaches operating temperature.

Can You Install It Yourself?

Many experienced enthusiasts can install a Granatelli slip-fit system themselves.

However, professional installation is a good idea when:

• Welding is required

• The exhaust needs fabrication

• Ground clearance is extremely tight

• You have a custom turbo system

• Exhaust routing is complicated

• You're unsure about sensor or emissions-component locations

Sometimes spending a little more time planning the location saves a lot of time correcting the installation later.

A Simple Installation Checklist

Before finalizing your cutout position, check all of these:

Is it after the catalytic converter?

Is it downstream of the oxygen sensors?

Is the electronic gate at least approximately 18 inches from the header collector?

Does it have enough ground clearance?

Is it tucked above or within the chassis profile whenever practical?

Does the exhaust outlet point away from sensitive components?

Can the wiring be routed away from heat and moving components?

Can the valve and motor be serviced later if necessary?

Is there enough room for the exhaust turndown?

Will the system clear speed bumps, driveways and trailer ramps?

If the answer is yes across the board, you're probably looking at a much better installation location.

Watch a Granatelli Slip-Fit Cutout Installation

Want to see how a Granatelli electronic exhaust cutout is actually positioned and installed?

Granatelli Motor Sports walks through a slip-fit cutout installation here:

https://www.youtube.com/watch?v=7oazdw4kLmE

Watching the system installed on an actual vehicle can make the placement considerations much easier to understand.

The Bottom Line

So where should you install an exhaust cutout?

The ideal location is generally:

After the catalytic converter and oxygen sensors

At least approximately 18 inches away from the header collectors for Granatelli electronic systems

Before the mufflers or other downstream restriction you want to bypass

Tucked high enough to maintain proper ground clearance

Positioned so hot exhaust is directed safely away from the vehicle

There isn't one measurement that works for every vehicle.

Your Camaro may have different packaging than a Corvette.

Your Mustang may be different from a truck.

A turbo vehicle may require a completely different location from a naturally aspirated street car.

That's why the best exhaust cutout installation starts before anyone reaches for a saw or welder.

Look at the entire exhaust system first.

Find the restrictions.

Find the sensors.

Find the available space.

Then position the cutout where it can do its job without creating another problem.

A properly positioned Granatelli exhaust cutout gives you exactly what the system was designed to provide:

Normal exhaust when you want it.

Open exhaust when you need it.

At the push of a button.

Shop Granatelli Exhaust Cutouts

Explore Granatelli electronic, manual, round, oval, single, dual, slip-fit and weld-in exhaust cutout systems:

https://granatellimotorsports.com/collections/exhaust-cutouts

Granatelli Installation Instructions

Official Granatelli electronic exhaust cutout installation instructions:

https://granatellimotorsports.com/pages/instructions

Related Granatelli Videos

Slip-Fit Electronic Exhaust Cutout Installation

https://www.youtube.com/watch?v=7oazdw4kLmE

Installing an Oval Exhaust Cutout on Round Exhaust Tubing

https://www.youtube.com/watch?v=EZBb_Q33Fxs