The real problem with DPF exhaust is regen heat. Exhaust leaving the diesel particulate filter can reach roughly 1,100 degrees, and a bad tailpipe design can push dangerous heat out the back of the truck. That is why we built CoolCuff as an inline mixer that pulls outside air into the hot exhaust stream before it exits the tip. This only works if the vent shape and inlet angle are right. We generated the inlet geometry in the computer, formed it to the required angle, and validated it with thermocouples placed at the DPF, along the exhaust, near the tip, and even at the spare tire. The result is a system designed to beat stock exhaust temperatures during regen, while avoiding the excessive tailpipe heat seen elsewhere. On the dual exhaust system, outlet temperature is another 40 to 50 degrees cooler than the single system.
The segment begins with the exhaust tip itself, a polished 304 stainless steel piece that serves as the visible end of Banks' diesel exhaust system. The discussion quickly shifts from appearance to function, focusing on the Cool Cuff, an inline device designed to address a specific problem with diesel particulate filter exhaust temperatures during regeneration.
Banks describes the Cool Cuff as a mixer installed in the exhaust stream downstream of the DPF. During a regen event, exhaust leaving the diesel particulate filter can become extremely hot, on the order of 1,100 to 1,200 degrees. The Cool Cuff introduces outside air into that hot exhaust before it exits the tailpipe. Its vents act as mixers, while the outer cuff directs incoming air into those vents so the cooler ambient air blends with the exhaust flow and reduces outlet temperature.
To verify the effect, Banks instrumented a stock truck with thermocouples placed along the exhaust system. Measurements were taken back at the DPF, six inches out from the exhaust outlet, and right at the tip. They also placed a thermocouple on the spare tire to confirm that nearby components would not be overheated. This testing established a baseline for stock exhaust temperatures during regeneration and provided the reference point for the Cool Cuff design.
Gale explains that Banks first documented the stock truck's exhaust temperatures, then designed the Cool Cuff system to outperform that baseline by producing lower outlet temperatures. According to the discussion, Banks' system runs cooler than stock, while other aftermarket systems can run hundreds of degrees hotter than stock during regen. That difference is presented as a major engineering concern, because excessively hot tailpipe discharge can create hazards near the vehicle.
The transcript highlights the severity of those elevated temperatures with a simple demonstration claim: during regeneration, a piece of cardboard held two feet from the tailpipe of some hotter aftermarket systems can catch fire. Banks emphasizes that it did not want to produce anything with that kind of behavior. The point is framed as an engineering and safety decision, with the company presenting the Cool Cuff as a scientifically developed solution to control exhaust outlet temperature rather than simply accepting hotter-than-stock regen conditions.
The Cool Cuff's effectiveness depends on the geometry of its air inlets. Banks says the inlet shape was generated in the computer rather than created as a simple stamped feature bent into place without analysis. The resulting vent form is described as unique, with both the shape and the angle playing a critical role in how outside air is drawn in and mixed with the exhaust stream.
After the inlet geometry was developed, Banks used an engineering die to bend the vents to the exact angle specified by the computer design. The company stresses that this is not an arbitrary manufacturing step: if the vents are bent too far in or too far out, the device does not work correctly. In other words, the angle is critical, and the shape is critical. Banks says the design was then validated with field measurements, tying the manufactured part back to real-world thermal test data.
In the finished assembly, the mixing device is welded into the exhaust pipe, and the cuff then slides over it facing forward. As the vehicle moves, outside air enters the forward-facing cuff, is directed through the shaped vents, and flows into the hot exhaust stream before the gases exit the tip. The intended result is a noticeably cooler exhaust discharge at the outlet.
The segment closes with a comparison between Banks' single and dual exhaust configurations. The dual exhaust system is said to be even cooler than the single system, by roughly 40 to 50 degrees. That final point reinforces the overall engineering story: Banks measured stock behavior, identified the thermal risks associated with hotter aftermarket exhausts during regen, and developed a shaped, angle-sensitive air-mixing device to reduce tailpipe temperatures below stock levels.