Engine Brake vs Jake Brake
Understand the difference between engine brakes and Jake brakes, how they work, costs, and which is best for mountain driving.
If you’re new to mountain driving, you’ve probably heard the terms “engine brake” and “Jake brake” used interchangeably. But they are not the same thing. An engine brake is any system that uses engine compression to slow the vehicle. A Jake brake is a specific brand of compression release brake made by Jacobs Vehicle Systems. This guide explains the difference, how each works, and what it means for your wallet and your driving.
What Is an Engine Brake?
An engine brake is a general term for any device that converts the engine from a power producer into a power absorber. Instead of burning fuel to push pistons, the engine uses compression to resist the drivetrain. When you engage an engine brake, the engine works against itself, slowing the truck without using the service brakes.
There are two main types of engine brakes: exhaust brakes and compression release brakes. Exhaust brakes trap pressure in the exhaust system, creating backpressure that slows the engine. Compression release brakes, like the Jake brake, open exhaust valves at the top of the compression stroke, releasing compressed air and losing energy.
What Is a Jake Brake?
A Jake brake is a brand name for a compression release brake. It is manufactured by Jacobs Vehicle Systems, and the name has become generic, like Kleenex for tissues. The Jake brake works by opening the exhaust valves at just the right moment during the compression stroke. This releases the compressed air, so the energy built up during compression is not returned to the piston. The result is a strong retarding force that helps slow the truck on long descents.
Jake brakes are common on heavy-duty diesel engines, especially in Class 8 trucks. They are known for their distinctive loud rattle, which is why many towns have signs prohibiting their use. But not all engine brakes are Jake brakes, and not all Jake brakes are the same.
Key Differences Between Engine Brake and Jake Brake
The main difference is scope. Engine brake is the umbrella term. Jake brake is one specific type. Here is a quick breakdown:
- Engine brake: Any system that uses engine compression to slow the vehicle. Includes exhaust brakes and compression release brakes.
- Jake brake: A compression release brake made by Jacobs. It is a type of engine brake, but not all engine brakes are Jake brakes.
- Exhaust brake: Another type of engine brake that uses a butterfly valve in the exhaust to create backpressure. Quieter than a Jake brake, but less powerful.
In practical terms, when someone says “engine brake,” they might mean any of these. When they say “Jake brake,” they mean the specific Jacobs product.
Cost Comparison: Engine Brake vs Jake Brake
If you are buying a new truck, the engine brake is often an option. Here are typical costs as of 2026:
| Option | Typical Cost (Installed) | Notes |
|---|---|---|
| Exhaust brake (aftermarket) | $800-$1,500 | Quieter, less retarding power |
| Jake brake (aftermarket) | $2,500-$4,000 | Strong retarding, louder |
| Factory-installed engine brake | $1,500-$3,000 | Included in new truck price, varies by OEM |
| Retrofitting a Jake brake on older engine | $3,000-$5,000 | Requires engine compatibility |
These are rough ranges. Actual prices depend on your engine model, labor rates, and whether you buy new or used parts. For a used truck, a Jake brake can add $2,000 to $5,000 to the resale value, so it is a good investment if you run mountains.
Performance in Mountain Driving
In the mountains, retarding power is critical. Jake brakes provide the strongest retarding force, typically 70% to 80% of engine horsepower. For example, a 500 hp engine with a Jake brake can deliver 350 to 400 hp of retarding power. Exhaust brakes are weaker, usually 30% to 50% of engine horsepower.
That difference matters on long descents. With a Jake brake, you can maintain a safe speed without riding the service brakes, which prevents brake fade. With an exhaust brake, you may need to use the service brakes more often, increasing the risk of overheating.
However, Jake brakes are loud. Many municipalities ban their use, so you may need to switch to an exhaust brake or rely on service brakes in those areas. Some newer Jake brakes have a “quiet” mode that reduces noise, but it also reduces retarding power.
How to Use an Engine Brake Safely
Using an engine brake correctly is a skill. Here are steps to get started:
- Read your owner’s manual: Know the specific controls for your engine brake. Some are automatic, some are manual.
- Engage before the descent: Do not wait until you are already speeding. Activate the engine brake at the top of the hill.
- Select the right gear: Use a lower gear to keep engine RPM in the effective range, usually 1,500 to 2,100 RPM for a Jake brake.
- Monitor your speed: The engine brake is not a cruise control. You still need to manage speed with the service brakes if you exceed your target.
- Practice on a mild grade first: Do not try a steep mountain pass on your first attempt. Find a gentle slope and get a feel for the retarding force.
Maintenance and Longevity
Engine brakes require regular maintenance. Jake brakes have moving parts that can wear out. Common issues include:
- Solenoid failure: The solenoids that control oil pressure can fail, costing $200-$400 each.
- Adjustment: Valves need periodic adjustment, typically every 50,000 miles, costing $300-$600.
- Oil quality: Engine brakes rely on clean oil. Change oil on schedule to prevent sludge buildup.
Exhaust brakes have fewer moving parts, so they are generally more reliable, but the butterfly valve can stick if the exhaust gets corroded. Regular inspection is key.
FAQ
Is a Jake brake the same as an engine brake? No. A Jake brake is a specific type of engine brake. Engine brake is the general category that includes Jake brakes and exhaust brakes.
Can I install a Jake brake on any diesel engine? No. Jake brakes require specific engine designs with overhead camshafts or pushrods that can accommodate the compression release mechanism. Check with Jacobs or your engine manufacturer for compatibility.
Are engine brakes illegal in some areas? Yes. Many towns and counties have noise ordinances that prohibit the use of compression release brakes, especially Jake brakes. Look for signs that say “Engine Brake Prohibited” or “No Jake Brake.” Exhaust brakes are usually quieter and may be allowed.
How much does a Jake brake cost to install? Aftermarket installation typically runs $2,500 to $4,000, including parts and labor. If you buy a new truck, the factory option may be cheaper, around $1,500 to $3,000.
The Bottom Line
For mountain driving, a Jake brake is the gold standard. It provides the strongest retarding force, which keeps your service brakes cool and your descent safe. But it costs more and is louder. An exhaust brake is a quieter, cheaper alternative, but it may not be enough for steep grades. If you run mountains regularly, invest in a Jake brake. If you only see hills occasionally, an exhaust brake might suffice. Know the difference, understand your truck, and practice before you hit the big passes.