You grip the steering wheel, foot hovering above the exhaust brake pedal as you descend a steep 6% grade at 60 mph while hauling 45,000 pounds of cargo. The weight pushes you forward. Your service brakes heat up. You wonder – should I hit the exhaust brake or not?
It’s a common question for drivers of heavy-duty diesel trucks equipped with this supplemental braking system. Let’s break down how exhaust brakes work, when you should use them, potential downsides, and find the right balance for your specific driving needs.
Here’s a quick answer:
No, you should not use your exhaust brake continuously. Use exhaust brakes judiciously depending on driving conditions and loads. Employ them when towing heavy cargo, descending steep grades over 45mph, or to supplement brakes in stop-and-go traffic. Avoid residential areas. Overuse risks premature wear, noise complaints, and poor drivability. Check your manual for suggested usage rates.
What the Heck is an Exhaust Brake?
First things first – what exactly does this thing do? Essentially, an exhaust brake utilizes backpressure created in the exhaust system to slow a diesel engine down. Here’s a simple analogy:
Imagine you’re blowing up a balloon. As you exhale air into the balloon, you feel resistance against your lungs making it more difficult to exhale. This creates backpressure. Now picture a cork shoved in the end of the balloon. This cork represents an exhaust brake – it restricts airflow out of the engine, forcing the pistons to work harder to push exhaust gases out. This transfers energy from the drivetrain to the exhaust system to slow the engine RPMs and vehicle speed.
Unlike your conventional friction brakes, exhaust brakes vary intensity based on engine load. More cylinders pumping means more resistance created. This makes them exceptionally useful when going downhill or towing heavy loads. The extra resistance helps controlling speed without constantly riding your service brakes.
Key Benefits of Exhaust Brakes
Using an exhaust brake integrated into your driving offers some compelling benefits:
- Preserve Your Brakes – Exhaust brakes significantly extend the life of your standard friction brakes. By generating up to 50% or more of your total braking effort, they relieve your brake pads and rotors from excessive heat and wear. This saves you money down the road on brake repairs.
- Enhanced Safety – Supplementing your wheel brakes with an exhaust brake gives you an extra tool for controlling your vehicle, especially in critical situations like steep descents. The added braking force helps maintain a safe speed and save your standard brakes from overheating or sudden failure.
- Improve Fuel Economy – While counterintuitive, exhaust brakes actually improve fuel efficiency in many scenarios. By using transmission gearing and engine resistance to slow down, you save on wasted fuel from braking. Less brake use also prevents costly drag from a stuck brake caliper.
- Reduced Maintenance Costs – In addition to extending brake life, the engine braking of an exhaust brake helps optimize engine temperatures and keeps your turbocharger cleaner. This supports better engine performance and reliability over high mileage use.
So clearly exhaust brakes provide some compelling benefits. But when should you use them?
Recommended Usage Guidelines
The optimal use of your exhaust brake depends greatly on your vehicle, load, road conditions and preferences. But here are some general guidelines:
Towing Heavy Loads
Any time you are towing near or at the maximum tow rating, employing your exhaust brake helps maintain safe speeds without overtaxing your service brakes on descents. This includes towing heavy 5th wheel RVs, large boat trailers, equipment haulers or livestock trailers.
Long 6%+ mountain grades generate significant inertia and brake heat. Set your exhaust brake to the maximum setting to help control descent speeds above 45 mph. For speeds under 45 mph, you can reduce the exhaust brake intensity.
For moderate traffic jams, you can use low exhaust brake settings to supplement your brake usage. But trying to replicate the feel of your friction brakes usually does not work well. Use judiciously and disengage if causing you extra fatigue.
Outside of the above scenarios, relying solely on your friction brakes is typically best for everyday driving. But to help extend brake life, using low exhaust brake settings when slowing down, especially from higher speeds, can’t hurt. Just don’t overdo it.
Avoid Around Homes/Businesses
While exhaust brakes are quieter than ever, they still amplify engine noise, particularly when set to higher intensities. Be courteous and switch off your exhaust brake near homes, hotels, hospitals or other noise-sensitive areas.
As you can see, properly leveraging your exhaust brake brings advantages like safety, savings and engine benefits. But several factors influence ideal usage.
What’s the Downside of Running My Exhaust Brake Too Much?
While a valuable supplemental tool, exhaust brakes bring some downsides when used to excess:
- Increased Noise – Even with advanced muffler systems, an exhaust brake at higher settings significantly increases loudness versus your engine’s normal noise signature. This can create noise complaints and even violations depending on local laws.
- Greater Vibrations – The added resistance loads up the crankshaft and powertrain, sending more vibrations through the chassis. This leads to faster wear on engine mounts, gearbox components and interior parts prone to shimmying loose.
- Premature Wear – The backpressure created by your exhaust brake places extra strain on exhaust components like the DPF, muffler and catalytic converter. It also loads up bearings, servo pistons and your turbo. This wears parts out quicker.
- Poorer Driveability – While perhaps not an issue for experienced drivers, those newer to exhaust brakes may find the sensation of the engine holding back against you fatiguing. It just does not coast or handle like typical driving. Adaptation takes time.
How Do I Find the Right Balance?
Here is a quick cheat sheet to help strike the ideal exhaust brake usage rate for your specific needs:
|Towing Heavy Loads
|Descending Steep Grades
Remember, today’s heavy diesel pickups and tractor trucks likely feature an exhaust brake specifically calibrated for your engine and use case. Checking your owner’s manual provides key details like:
- Suggested braking intensities for given vehicle weights and grades
- RPM ranges when system engages
- Proper operation and care
While tempting to just lock the exhaust brake on and forget it, each mile comes with tradeoffs. Finding the right balance boosts savings on brake repairs while minimizing disruptions to residents, component wear and performance. Test different settings across scenarios to discover your optimal mix of friction and exhaust braking for both safety and efficiency.
With smart usage tailored to your needs, your exhaust brake becomes an indispensable ally offering you precision control hauled loads demand. Stay safe out there on the long and winding road!
1. What vehicles come equipped with exhaust brakes?
Exhaust brakes are primarily found on medium and heavy-duty diesel trucks, usually F-250 and larger pickup trucks as well as Class 7 and Class 8 tractor trucks. Most modern diesel engines offered in these larger vehicles will have an integrated exhaust brake.
2. When does my exhaust brake activate?
Most exhaust brakes have a specific RPM activation range that varies by vehicle model. It typically engages between 2000-2500 RPMs on deceleration and disengages around 1200 RPM. Drivers can manually activate or change the intensity at any speed.
3. Can using an exhaust brake damage my engine?
When used properly and not excessively, an exhaust brake puts no more strain on your engine than going downhill without one. But running at maximum intensity all the time can potentially overload components like the turbocharger and emissions equipment over time.
4. What maintenance is required for an exhaust brake?
Exhaust brakes contain minimal moving parts and operation is usually automatic and requires no special maintenance. The biggest service need is checking and replacing exhaust components like the DPF, which does wear faster with very high exhaust brake use.
5. Will an exhaust brake disrupt my neighbors?
Exhaust brakes significantly amplify diesel engine noise, so using higher settings near homes, hotels or hospitals is not recommended. Most exhaust brake systems allow you to reduce or disable operation to prevent noise complaints.