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What Is Exhaust Braking?

What Is Exhaust Braking?

The hills and valleys can provide you with some incredible landscapes to enjoy. However, they’ll do a number on your brakes.

That’s especially if they’re your only means of slowing down or stopping your vehicle.

Larger trucks, especially ones engineered for towing heavy loads, will often come with an exhaust braking system to assist with braking. So what is exhaust braking? Let’s see!

What Is Exhaust Braking?

Many modern diesel engines include a feature known as exhaust braking. When activated, an exhaust brake assists the braking system with slowing down a vehicle.

It doesn’t matter how heavy the load is. The exhaust will provide a bit of assistance that can significantly help with navigating steep or long grades going down hills and mountains.

The benefits of using an exhaust brake are increased control and extending the life of your brakes. Riding your brakes to maintain control of your vehicle down a mountain pass or hill can be very hard on your braking system and potentially cause damage.

Keeping your speed in check when going down steep grades helps you maintain control of your vehicle and any trailers you might also be towing.

What’s the Difference Between Engine Brake and Exhaust Brake?

In addition to a traditional braking system, many trucks come with additional braking systems like engine brakes and exhaust brakes. While they may sound similar, their effectiveness and how they get the job done are quite different. Many errantly confuse the two, but it’s important to know the difference.

Both gas and diesel vehicles can have engine brakes. As you might guess, an engine brake relies on the engine to assist the brakes with slowing and stopping a vehicle.

Whether it’s a gas or diesel engine, the components involved will differ. 

The force needed to slow a gasoline vehicle begins when the driver takes their foot off the gas pedal. This closes the throttle and decreases the amount of air in the engine, which creates a vacuum. The force created by the vacuum makes it more difficult for the engine’s cylinders to work, which slows the vehicle.

How Diesel Engines Differ

However, diesel engines function very differently than gasoline engines. A diesel engine doesn’t have the same throttle valve type as a gas engine. As a result, manufacturers will often add one to the exhaust side of the vehicle to create the pressure as the pistons force exhaust out. It’s this pressure that diesel engines use to create more resistance for the engine to work.

The increased force ultimately slows the vehicle down and assists the brakes in the process.

When it comes to exhaust brakes, you’re rarely going to find them on gasoline-powered engines. This is because gasoline engines don’t typically pump nearly as much air as diesel engines through the engine once the throttle valve closes. 

Exhaust brakes close off the exhaust and create pressure that makes it difficult for the pistons to move the engine. It is one of the most effective means of slowing a vehicle, and many drivers find they rarely have to use their actual brakes when going down steep grades.

Pro Tip: Checking your brakes often is important! We uncovered How Do You Check RV Brakes?

Close up of car brake system.
Engine and exhaust brakes perform different tasks while being used.

How Does Exhaust Braking Work? 

An exhaust brake essentially closes off the path exhaust would generally take to exit the vehicle. This process creates back pressure in the manifold and cylinders, making the engine work harder. This drastically slows even the heaviest of vehicles while rarely relying on brakes. A driver can typically activate the system with the press of a button, and it will respond when necessary.

When Should You Use an Exhaust Brake?

If your vehicle has an exhaust brake installed, you’ll want to use it when navigating hills and mountains with a long or steep decline. It will help you maintain the speed of your vehicle and control when going downhill. Long and steep grading declines can be challenging to navigate as they can quickly overheat your brake pads and other essential components. 

Without an exhaust brake, your primary means of stopping your vehicle will be your brake pads. Burning through them will leave you in a terrifying and dangerous situation, especially if your trip involves more mountain passes or steep grade declines.

Should I Drive With My Exhaust Brake On?

Using an exhaust brake will not harm your engine in any way. The exhaust brake will only activate on an as-needed basis when it detects your brakes need a bit of help.

Many drivers will activate their engine brakes as often as possible to extend the life of their brakes.

However, others only activate their exhaust brakes when towing or navigating mountains and hills. How often you choose to use your exhaust brake is up to you, but there is very little to worry about harming your engine.

Woman happily out sun roof driving through mountains.
Drive through the mountains on your next adventure safely by knowing how to correctly use your brakes.

Are Exhaust Brakes Loud?

Exhaust brakes are not loud. Typically, when people complain about it being loud, what they’re hearing is an engine brake. When a semi uses its engine brake to slow down, it can create a very loud and disturbing noise. 

In fact, they’re so obnoxious that many communities have laws regarding the use of engine brakes. Drivers caught using their engine brakes in these “no engine braking” zones can receive a citation or fine by local law enforcement. 

Pro Tip: There’s a lot to know about your vehicle and RV brake system. We took a closer look at What Is a Trailer Brake Controller?

Can You Put an Exhaust Brake on a Gas Engine?

No, gas engines cannot draw in enough air to create the required vacuum of an exhaust brake. While you could go through all the effort of installing one, it would produce minimal results and only increase the likelihood of damaging expensive and sensitive components in the engine.

Is an Exhaust Brake Worth It?

An exhaust brake is a great way to not only extend the life of your brakes but also stay in control of your vehicle. Steep grades can do a number on your brakes, and you can lose control of your vehicle if you build up too much speed or momentum.

Using an exhaust brake keeps your speed in check without overtaxing your brake pads. If your vehicle has an exhaust brake, it’s a good idea to use it when driving.

Does your vehicle have an exhaust brake? Tell us in the comments!

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Bob

Tuesday 22nd of March 2022

Brakes are not the only way to slow down with a gas engine. How cone you didn't mention downshifting to a lower gear?

Bruce Parker

Tuesday 22nd of March 2022

My 2018 Sprinter diesel van does not have an exhaust brake, and I have postponed researching an aftermarket install until the drivetrain warranty expires. I’ve not found one yet.

Deborah

Tuesday 22nd of March 2022

Can an exhaust brake be added to an older truck, f250 2002?

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