Does this sound familiar?
A driver towing a heavy load or driving a big motorhome has finally made it – he has crested the top of that mountain grade and it’s all downhill from here. He peers down the highway in front of him running down the side of the mountain and realizes he has a new set of challenges.

He has a four mile, seven percent grade to navigate with tons of metal riding behind him and all he has are a set of overworked vehicle brakes to slow his growing momentum as he starts to gain downhill speed without so much as a tap on the throttle.

He looks to his right over the edge of the guardrail and can’t see the bottom! Returning his gaze to the road in front of him he sees, becoming clearer every moment, a line of vehicles at a stop sign at the bottom of the hill. And all of a sudden there are butterflies coming to life in his stomach and they are beating their wings furiously.

The driver realizes he is in a "free fall" with no speed retarding assistance from his engine, so he begins to pump the brake pedal. While he feels some temporary assistance, and a little security from knowing he is no longer rocketing down the side of a mountain, he notices that the blood is leaving his knuckles as he grips the steering wheel. He downshifts and his RPMs begin to soar, but his speed continues to increase. So as the skin covering the back of his hands becomes almost transparent, he decides to take the next step – the final option.

He stands on the brake pedal with such force that he lifts himself out of the driver’s seat far enough to slip a two by four between him and the upholstery. Finally, his momentum begins to slow – a little. Now his sense of smell kicks in and as he sniffs the air, he smells something. What is that? Can a person smell heat? It sure seems like something is burning and he recognizes the pungent odor of overheating brakes.

As his brakes begin to roast, they also begin to fade and lose braking effectiveness. The driver realizes that he is driving on a wing and a prayer, and he hopes for the best as his lively descent down the mountain grade continues unabated.

At its very center, the problem arises from the way the engine runs when there is no pressure on the throttle. When a gasoline engine is idling, the throttle body butterfly rests in a closed state. The butterfly cuts off air flow so the engine generates vacuum as the pistons are continually trying to draw air into the cylinders. This vacuum has a retarding effect on engine output and automatically provides some braking assistance on downhill grades when the driver’s foot is not on the throttle.

This butterfly-generated vacuum assistance does not exist in a diesel engine. Even when there is no throttle pressure, the diesel continues to pump air into the engine.

On the other hand, exhaust brakes are relatively quiet. They build the back pressure required to retard the vehicle’s momentum without producing all the clatter.

In the early 1990s this "big rig" technology became available to pickup and motorhome owners.

On most downhill grades exhaust brakes engage automatically to help slow the vehicle’s momentum. This permits the diesel-powered pickup or motorhome to stop quicker. Exhaust brakes also save wear and tear on the wheel brakes. Finally, and most importantly, safety is increased and the butterflies in the driver’s stomach go back to sleep and the driver is truly in control of his rig.

U.S. Gear offers exhaust brake alternatives
Cutting off air to a gasoline engine is not a problem. They are designed to operate with a throttle body. Like human beings, though, if diesels don’t get air, they die. Butterfly valves, however, are the most effective way of blocking flow in the vehicle’s systems. That’s why butterflies are used in exhaust brakes "behind" the engine for diesels.

U.S. Gear offers two types of exhaust brakes – both utilize butterfly valves to create back pressure.

As you can see from the graph, the orifice (hole) regulated "Standard" model builds maximum pressure at higher RPMs.

If you drive a small pickup or motorhome, and you rarely visit mountain communities, then the "Standard" is the perfect solution to help your vehicle perform up to its braking potential.

The "Super Duty" D-Celerator
U.S. Gear’s "Super Duty" model also uses a butterfly to create back pressure. But unlike other exhaust brakes, the "Super Duty" D-Celerator has a patented turbo-inspired waste gate to manipulate the amount of pressure built up in the engine. This means that when the butterfly is closed, it is 100% closed with no exhaust leakage because there are no orifices (holes) in the butterfly. Remember, the only reason for the orifices in other exhaust brakes is to keep you from destroying your engine by creating excess pressure at higher RPMs. Since the "Super Duty" model has a waste-gate bypass, back pressure is bled off only when necessary.

The waste-gate valve spring is pre-set at the factory to open only as often and as much as necessary to avoid damage to your specific diesel engine.

Since most diesel owners ideally run at 1,500 – 2,000 RPMs, the "Super Duty" model is the clear winner in working with the engine to provide maximum braking performance.

So if you sometimes tow heavy loads, or drive a large motorhome, or often drive in hilly or mountainous areas, then the "Super Duty" D-Celerator is for you. Even if those situations don’t describe your driving patterns, you may decide to use the "Super Duty" model simply to save wear and tear on your vehicle brakes.

Why U.S. Gear?
U.S. Gear is proud to be the only manufacturer to offer two models of exhaust brakes. The "Standard" model provides effective braking assistance for light duty applications under non-strenuous conditions. The patented "Super Duty" D-Celerator renders superior braking support at both low and high RPMs, and also in extreme environments such as heavy vehicles or loads and mountainous regions.

The D-Celerator advantage includes the fact that both models are the only computer-controlled exhaust brakes in the industry. This gives U.S. Gear the freedom to add extra innovations such as the outstanding "cycle feature." The cycle feature eliminates a problem common to the exhaust brake industry. Specifically, the cycle feature does away with the soot build-up from diesel exhaust which causes the butterfly to bind, generally from lack of use.

In addition to their "self-maintenance" characteristics, stainless steel components also extend the durability of the U.S. Gear diesel exhaust brakes.

Because all D-Celerators are installed downstream in the exhaust system where there is more space, U.S. Gear’s exhaust brakes have an oversized casting. This means that since the exhaust brake is not in use 95% of the time, the open butterfly and pivot shaft don’t present a barrier to the swirl of diesel exhaust gases exiting the turbo. In fact, the D-Celerators actually improve flow by increasing the area available in the exhaust stream.

D-Celerators are available in a wide variety of models ranging from 2.5" to 4" and either air-activated or electric-activated. U.S. Gear’s exhaust brakes are easy to install and are proudly made in the USA.

To top it all off, the D-Celerators are accompanied by the best warranty in the industry and both models have a 90 day customer satisfaction guarantee.