When looking at aftermarket modifications that help during towing most people think they need to increase the power of the truck. This comes from seeing trucks struggle to get up steep grades, or having trouble slowing down. 

The LoadLeash

Through years of experience in the automotive world, we continue to see the same thing over and over again … people always think of going faster or towing more, but there is more science behind it. Isaac Newton discovered a long time ago that an object in motion will stay in motion, but slowing down the object is a whole other story.

The LoadLeash is a direct bolt-on, and does not add any height to the valve cover heights.

Fortunately, the minds at Pacbrake have done the research to solve such a dilemma, and designed an engine brake to address these safety concerns. Engine brakes are used on large engines, usually above 9-liters, to achieve high braking efficiency where small engines utilize an exhaust brake. However, Pacbrake thought that it would be really cool to have an engine brake for a smaller engine and developed LoadLeash.

Our trucks all have brakes – or so we hope – and they do an adequate job when the truck is unloaded. The issue arises when we start hauling the amount of weight that those diesel engines we love so much can truly pull. A new 2016 Ram 3500 may very well be able to pull more than 30,000 pounds to the summit of a mountain pass.

If you are unfamiliar with the general operation of a four-stroke internal combustion engine this could seem slightly technical, but part of the beauty of this product is that it really is quite simple, in both operation and design.

The purple part designates the LoadLeash installed.

Before we get into how the LoadLeash improves the engine braking of your truck, we will first walk you through how braking is controlled by your truck in its factory form. The 6.7-liter Cummins Ram trucks are equipped with what is known as a VGT (Variable Geometry Turbo), which can function as an exhaust brake.

When the Tow/Haul mode button has been depressed, along with the exhaust brake button, the ECU commands the VGT to close its vanes which generates resistance to exhaust gases escaping the engine, thus slowing down the engine. The ECU monitors the RPM and downshifts to increase RPM, and consequently the efficiency of the exhaust brake. However, this exhaust brake set up can only generate a limited amount of retarding horsepower.

Once the balance is exceeded due to the combination of grade steepness and overall weight, the braking performance of the VGT becomes less effective at slowing the vehicle and forcing you to rely on heavy braking to slow down and remain safe. While parts and labor prices for brake components vary from truck to truck, the prices only seem to be on the rise, and installing the LoadLeash on your tow vehicle can actually extend the life of your brakes.

The load leash doubles the supplemental braking power for load control while still keeping the truck and occupants safe while reducing brake fade and increasing trailer brake life. The install is a straightforward bolt-on installation and doesn’t increase valve cover heights. Unlike traditional engine brakes which require expensive mufflers to dampen high noise levels, the LoadLeash is virtually silent.

How Does It Do What It Does

Simply put, the typical four-stroke diesel engine cycle consists of the intake stroke in which air passes the intake valve entering the combustion chamber as the piston travels downward, the compression stroke in which the piston travels upward to compress the air and fuel mixture to the point of combustion. The power or expansion stroke in which the expanding gasses force the piston back down, and the exhaust stroke in which the burnt air and fuel charge is expelled past the exhaust valve.

The LoadLeash shown in a mockup installation.

So the LoadLeash Engine brake functions by holding the exhaust valve slightly off their seats during the complete engine cycle. This system achieves two braking cycles: 

The first braking cycle is accomplished during the exhaust stroke when the piston is pushing the cylinder pressure past the open exhaust valve against the “closed” VGT. 

The second braking cycle occurs during the compression stroke when the piston is pushing the cylinder pressure past the open exhaust valve against the “closed” VGT.

With work being done on both the compression stroke and the exhaust stroke, the LoadLeash Engine Brake is performing retarding work on two engine cycles. In numbers the LoadLeash produces more than 300 units of braking horsepower when measured at the rear wheel.

That is serious braking control when you’re towing your heavy loads, and we know your brakes will be thankful as well. The improvement in braking can drastically be felt over 2,500 rpm, but the LoadLeash enables you to run at high RPM and to manually downshift less often. If you’re curious as to what kind of stopping power this equates to in a real world application, this graph does a solid job of depicting that.

The charts below were generated with a Dodge Ram 4500HD chassis cab with the Cummins ISB 6.7-liter engine. Between the truck and the load, there was a total weight of 21,000 pounds running down a 10 percent grade. 

You can see here that the power of the LoadLeash was able to bring 21,000 pounds from over 40 mph to less than 30 mph in a little over 10 seconds – that’s impressive performance! Pacbrake’s LoadLeash enables those of you that really put your diesels to work on a regular basis the peace of mind to run down nearly any grade without having to hit the binders. Additionally, should an emergency arise where you really need to bring your whole setup to a crawl in a hurry, you can imagine the deceleration should you combine the LoadLeash with some heavy braking.

Right now Pacbrake is offering a $400 mail in rebate ending May 31st, 2016 on the LoadLeash so if you are serious about towing some real weight, then check out Pacbrake’s website or give them a call. They will definitely make dreading steep grades a thing of the past!