Exhaust Vs Jake Brake: Loudness, Engine Damage, Pros & Cons

By February 13, 2022Uncategorized

Exhaust brakes are best for small trucks and pickup trucks. An exhaust brake can prevent a vehicle from going too fast while going downhill. They are quiet and easy to install as well.

Jake brakes generate maximum braking power for  a diesel engine. Jake brakes are for semi-trucks and other heavy diesel engine vehicles to make them stop.

These vehicles require high braking force. Because of the weight, it’s hard for service brakes to stop the vehicle quickly and safely.

After being around different trucks I have learned a lot about them. one thing always made me curious about trucks and it was engine braking.

Jake brakes and the sound they make, Exhaust brake and how they work? All of these thoughts were my concern back then.

I’m pretty sure you all might be thinking what is Jake or Exhaust Brake and what even the Engine braking is? 

Does it hurt the engine?  Do I need one?

In this article, I will dive deeper into this topic and discuss in detail, why it’s important to have a supplementary braking system in trucks.

I will help you to choose which one you should choose, also the following topics will be discussed:

  1. What is engine braking?
  2. Exhaust vs jake brakes comparison
  3. Why do you need a supplementary braking system
  4. Legal
  5. Sound
  6. Difference
  7. Engine damage
  8. Recommendation of which you should go for

Engine Braking is slowing down the car by simply releasing the gas pedal – this creates a vacuum inside the engine that will eventually slow down your vehicle. 

Exhaust Brake and Jake Brake are different methods of engine braking in diesel engines. So it’s important to understand Engine Braking first. 

To understand Engine braking, firstly you have to understand how an engine delivers power to the wheels.

How engine delivers power to wheel

 

The pistons are connected to a crankshaft which converts the linear motion into rotational movement. Then the rotational movement goes through the clutch and then to the transmission.

Transmission transmits the power to the driveshaft which spins the differential and then the wheels.

When the throttle body is closed during the combustion, the moving pistons create a vacuum inside the engine cylinders. The vacuum causes the piston to slow down which ultimately acts as a braking system causing the vehicle to slow down.

This is how engine braking works in gasoline-powered engines but this principle does not apply to diesel engines. Diesel engine combustion is not the same as the gasoline engine because there is no vacuum created by diesel engines.

Which is why diesel engines use exhaust or jake brakes to perform engine braking. Let’s talk about that next.

Exhaust Brakes Vs Jake Brakes

Comparison Jake Brakes Exhaust Brakes
Type Supplemental braking system Supplemental braking system
Stock No Comes stock in few vehicles
Sound Extremely loud Not so loud
Backpressure Low Higher
Fuel efficiency (MPG) No impact No impact
Tune required  Recommended Recommended
Legal Not everywhere Legal
Cost Low to medium Medium to high
Installation Harder Easy
Suitable for turbo Yes Yes

 

How It Works: Engine Brake Vs Jake Brake

An exhaust brake slows down the diesel engine by closing the air exhaust and creating backpressure. A butterfly valve attached to the turbo exhaust closes or restricts the exhaust flow of the engine.

Now somehow, the engine has to release all the pressure from its system, so the pistons were moving freely before without any restriction.

Now the exhaust is closed, the engine and pistons are applying really hard force to release the pressure and as we all are familiar with the third law of newton’s,

“ Every force has an equal and opposite reaction and force.” – The opposite reaction generates the braking force causing the engine to slow down.

This change of motion helps diesel vehicles in braking. The exhaust brake is not an effective option for heavy trucks because of its weight and the weight truck is towing.

Exhaust brake has valve can close – trapping exhaust gases. These trapped gasses create pressure causing pistons to slow down. Thus, engine braking.

 

The Jake brake system works by releasing the energy which is produced during combustion stroke.

The Jake braking system was patented by Clessie Cummins in 1965, The first one to make Jake brakes was the company called “Jacobs vehicle system” since then the brakes are called Jake brakes.

The Jake brake system is the opposite of exhaust braking. Instead of trapping exhaust gas and creating back pressure to slow the piston, the jake brake uses custom valve timing to release engine-produced energy before the piston goes down.

Jake brake releases the energy away before it can be used to push pistons down. Thus, engine braking.

Which muffler is your car right now?

Usage: Jake Vs Exhaust Brakes

Jake brakes are made and used for heavy trucks and vehicles because of their braking efficiency. Whereas exhaust brakes are used for smaller trucks that don’t require too much braking force. 

Jakes are really effective as compared to Exhaust brakes.

Due to major drawbacks such as loud sound which makes Jake brakes prohibited in inherited areas. Jake brakes can’t be used in every vehicle. Thus the exhaust brake is required to fill the gap.

 

Sound: Exhaust Vs Jake Brakes

Jake brakes produce an extremely louder sound than Exhaust Brakes. The exhaust brakes are much calmer as compared to Jake brakes.

The exhaust brake does produce a sound that is also a bit loud. But when it comes to Jake brakes, the exhaust brakes might sound like a baby in front of them.

Less noise is the reason why most truck companies are using an exhaust braking system as an OEM option now.

 

Fuel Efficiency: Exhaust Vs Jake Brakes

Both the Jake and exhaust brakes have no effect on fuel efficiency. Engine braking doesn’t use any fuel.

Fuel efficiency can be affected if you are going uphill because then the vehicle would be going against gravity and to gain acceleration, you have to burn more fuel.

 

Cost: Exhaust Vs Jake Brakes

Jake brakes are more expensive than exhaust brakes. The average cost of a Jake brake is around 2500$ according to the study of International Trucks.

Exhaust brakes are cost-friendly and they would cost around 1200-1400$ for example, BD diesel performance brakes. Prices can be different depending on the manufacturer.

 

Is It Legal?: Exhaust Vs Jake Brakes

The Jake brakes are illegal in many areas because of their loud sound. Whereas exhaust brakes are legal – even in residential areas.

Jake brakes are prohibited in drive-in inherited areas. Some highways allow trucks to drive with Jake brakes.

When you are going en route, you might have noticed the “NO Engine Brake” sign. This sign refers to Jake brakes.

When brakes are applied the Jake brakes make an excessively loud noise, just like gunshots.

Some people who love loud exhaust cars and trucks do love it. Some people are annoyed by the loud sound.

Why are Jake Brake & Exhaust Brake Only For Diesel?

Unlike gasoline engines, diesel engines do not have throttle bodies for controlling the amount of air coming into the engine cylinder for the compression stroke.

The diesel engine can not do engine braking on its own and that is why we need an Exhaust brake or a Jake Brake.

Compared to diesel engines, gasoline engines are very good at making engine vacuum because of their throttle body, gasoline engines do not need an exhaust brake or Jake brake for engine braking.

Only diesel engines require exhaust brakes or Jake brakes for engine braking. When we talk about exhaust brakes or Jake brakes we are talking about diesel engines.

Exhaust braking or Jake braking is something that most diesel engines need because they are heavy and they are not good at making engine vacuum.

There are two types of engine braking in diesel engines, commonly referred to as “Exhaust Brake” and “Jake Brake”. Both use the engine as a braking system to slow down the vehicle.

How Jake Brake Works (More Detail)

The Jake brake system works by releasing the energy which is produced during combustion stroke.

The Jake brake system is the opposite of exhaust braking. Instead of trapping exhaust gas and creating back pressure to slow the piston, the jake brake uses custom valve timing to release engine-produced energy before the piston goes down.

Jake brake works on 4 stroke diesel engines. Here is a diagram of 4 strokes diesel engine working without the Jake brakes:

Without jake brake, energy released will push pistons down

 

1 stroke is the Intake stroke when the piston moves down the camshaft, opens the intake valve, and allows air to come in. The 2nd stroke is compression where the piston goes up and compresses the air inside the cylinder.

3rd stroke is called combustion when the fuel ignites due to compression it releases energy and sends the piston down. 4th and last stroke is exhaust when the piston completes the combustion cycle and moves towards top of the cylinder, an exhaust valve opens for exhaust gasses.

Here is a diagram with Jake brakes installed:

With Jake Braking – energy is released out before pistons is fully pushed up.

As you can see the 2nd stroke is not the same. Jake brake opens the exhaust valve during the 2nd stroke or compression stroke to release all the pressure safely.

No pressure means no power and no power means that your diesel engine is not sending any power to the wheels but rather working as a braking system.

This braking system is considered to be the most efficient one. Here’s a YouTube video explaining how Jake Brake works:

Jake Brake: Pros & Cons

Jake Brake pros:

  1. Can generate maximum braking force
  2. Global compatibility
  3. Works for much heavier trucks and vehicles safely

 

Jake Brake cons:

  1. Excessive noise
  2. Not legal in many places
  3. Expensive (if compared to exhaust brakes)

Exhaust Brake: Pros & Cons

Exhaust Brake pros:

  1. Much cheaper than Jake Brake
  2. Low noise
  3. Legal in many places (due to low noise)
  4. Easy to install

 

Exhaust Brake cons:

  1. Less efficient compared to Jake Brakes
  2. Not recommended on heavy trucks

Which Is Better: Exhaust Or Jake Brake?

If you have a semi-truck, you need a really good accurate braking system and you will be driving on highways only, then the Jake brake is the best choice for you.

As far as the sound is not concerned then the Jake brakes are the optimal solution for truckers. If you are tired of replacing your service brakes then the Jake brakes are what you need.

If you are a person who lives in a residential area and has a pickup truck then exhaust brakes are good for you. Exhaust brakes are much less noisy and they are also legal.

Note: Neither of the braking systems can stop the vehicle only on its own. Both the exhaust and Jake brakes require service brakes too. Please do not ignore your service brakes, replace them on time to prevent any unfortunate event.

Final Thoughts

In this article, we compared two different engine braking methods (systems). We discussed in detail how both braking systems work and which one you should go with depending on your needs.

Depending on your engine and your vehicle you can choose between the Exhaust brake and Jake brake. If you are a trucker and you spend most of your time driving on the highway then Jake brake is your good to go.

For me, the exhaust brakes are a much more suitable option because my route is in a residential area, I don’t tow heavy trailers as well and I have got restrictions. So because of the loud noise, I can’t use the Jake brake, but the exhaust brake is all that I need.

Ifandi L.

Ifandi L.

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? Scream "STRAIGHT PIPEEEEE" at the top of your lungs and Ifandi will show up.

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