Dyno Cell 2 is being rebuilt to solve a real test problem: making big power is easy, but measuring it accurately and repeatedly under steady load is not. Our previous setup could do the job, but it did not give us the controllability, repeatability, and accuracy we were after. That matters when you’re chasing small changes in fuel economy, emissions, and power output. The new AVL engine dynamometer is built around steady-state control. It can hold RPM tightly, measure torque through a proper absorber and strain-gauge setup, and support long-duration testing instead of just short sweep pulls. That is critical for the kind of work we do, including crate engine, marine, military, and emissions development. Just as important, the cell gets a serious facilities-water upgrade with a dedicated cooling tower system. This setup is designed to reject the heat from continuous high-load operation, so we can run 1,000-plus horsepower around the clock for days at a time. The result is a dyno cell that gives us cleaner data, better repeatability, and the ability to validate engines the way real durability and emissions work demands.
Banks has completely gutted its second dyno room and is rebuilding it around three priorities: accuracy, repeatability, and control. The upgraded cell is also being designed to add engine-emissions measurement capability, which is increasingly important for the company's work. The previous setup, based on an older tailored SuperFlow design with SuperFlow controls and valving, no longer delivered the level of repeatability or measurement precision Banks wanted.
The central problem is that truly accurate engine data depends on test conditions being as consistent as possible, and real-world days are not identical. Atmospheric correction factors help, but they can also introduce error. For organizations trying to resolve extremely small differences, even half a horsepower matters. Banks emphasized that while some high-end racing teams spend heavily to climate-control dyno facilities and eliminate those variables, its own objective is different: to measure fuel economy, emissions, and small performance changes with confidence throughout the year. That required moving beyond hobby-grade or intermediate dyno systems to a more professional-grade installation.
Banks distinguished between dynos that can display impressive peak numbers during short sweeps and dynos that can hold high load accurately for long periods. Many systems can claim large horsepower capacity because they only need to absorb that power for a few seconds. What Banks needed instead was a dyno that could maintain engine speed within a couple of RPM while carrying substantial load continuously.
That requirement comes from the company's current programs, which include crate engines, marine engines, military engines, and emissions-related development work. Some military and marine applications now require emissions data in addition to durability and performance testing. The new cell is therefore being built to support long-duration, high-load operation with precise control, including tests lasting hundreds of hours. Banks specifically described a need to run at or near wide-open throttle for 400 to 800 hours, with roughly 85 percent of an 800-hour test at full load, and noted that one of its test cycles lasts 33 days. The facility is being designed to run 1,000 horsepower or more continuously, 24 hours a day, not just for a five- or six-second pull.
After a worldwide search, Banks selected AVL as the basis for the new dyno system. AVL, headquartered in Austria, was founded by Dr. Hans List in 1948 to advance diesel technology. From the beginning, the company was rooted in diesel-engine development, and its name refers to the List Institute for Internal Combustion Engines. Although AVL now works across a broad range of powertrain technologies, Banks highlighted its long history in diesel engineering as a major reason for the choice.
The company remains a long-term family operation. Around 1979, Helmut Hans List, Dr. List's son, took over leadership, and Banks noted that he still runs the company. That continuity mattered because Banks was not simply buying a large absorber; it was investing in a measurement platform from a company deeply involved in engine development and emissions evaluation. In Banks' view, if a company develops engine technology, it must also know how to measure performance and legal emissions output accurately. That is the capability this dyno-cell rebuild is intended to strengthen.
Banks explained the basic operating principle of the engine dyno using a current 2020 6.6-liter L5P Duramax as an example. The engine is coupled to the dynamometer through a driveshaft that includes an elastomeric coupling section. That coupling helps isolate the absorber from the engine's firing and torque spikes so those transient loads do not beat up the dynamometer. The shaft is effectively tuned for that purpose and uses very large universal joints.
The driveshaft connects to the absorber, which is the core of the dyno system. In this case it is a hydraulic dynamometer, meaning it converts engine horsepower into heat by moving large quantities of water through the absorber. The shaft enters the absorber and rotates clockwise, matching the engine's crankshaft rotation when viewed from the front of the engine. Precisely metered load water enters the absorber, and the rotating internal element reacts against the absorber housing. A torque arm attached to the housing carries a strain gauge, which measures the reaction torque. Once torque is known, horsepower can be calculated. Banks emphasized that when people refer to a dyno's horsepower rating, they are fundamentally talking about the capacity of this absorber.
The selected absorber has a maximum speed of 7,000 RPM, which Banks said is more than adequate for the diesel work planned in the cell and suitable for much of the gasoline testing the company might also want to perform there. Its steady-state rating is 1,033 horsepower and 1,844 lb-ft of torque. Those numbers are significant because they represent continuous capability, not a brief sweep.
Banks contrasted that steady-state rating with the much larger short-duration numbers many dynos advertise. This absorber can still handle a 3,000-horsepower or 3,500-lb-ft five-second blast, but that is not the expensive part of the problem. The real cost is in buying a system that can absorb and control substantial power continuously, day and night, for months if necessary. That distinction between transient capacity and true steady-state durability is central to the entire rebuild.
A major part of the AVL system is its water-management architecture. Process water from the facility enters an upper tank that effectively decouples the absorber's internal water circuit from the facility supply. The tank uses a large float valve to maintain water level and feeds a Grundfos pump by gravity. Banks specifically called out Grundfos as a pump supplier it already trusts for other applications.
From that reservoir, the pump sends water through internal plumbing to the load-control circuit. The key feature is that the pump speed is controlled by the same software that manages the rest of the dyno. As a result, pressure at the load-control valve remains constant regardless of fluctuations in the facility water system. Banks stressed that this arrangement is entirely decoupled from facility pressure variations. In practical terms, the dyno creates its own stable hydraulic conditions, which is essential for repeatable load control. Because the absorber turns engine output into heat, the whole assembly functions, in Banks' words, like an extremely expensive water heater.
To remove that heat, Banks is building a substantial facility-water system centered on an Evapco cooling tower. A large stainless-steel tank, holding a few thousand gallons, will be installed at ground level and divided into hot and cold sections. Hot water from both dyno cells will flow through two 8-inch pipes into the hot side of the tank. From there, water will be pumped at roughly 400 gallons per minute up to the cooling tower, which will sit on a framework above the tank.
The Evapco evaporative unit uses twin squirrel-cage blowers to force air through the tower, and an outlet assembly on top carries the hot discharge air farther away from the intake side. The system is driven by a 20-horsepower, 480-volt, three-phase motor producing 41,000 CFM of airflow. After passing through the tower, the cooled water drains back through another 8-inch pipe into the cold section of the tank. From that cold side, pumps feed a manifold supplying intercoolers, jacket-water coolers, the absorber load-water reservoir, and other cooling demands in Cell 2. This infrastructure is what makes continuous high-power operation possible.
Cell 2 is being built around this new controlled cooling and dyno package, while Cell 1 still uses a more traditional arrangement. Banks said the older setup remains workable and has been refined as much as possible, but it still suffers from unstable conditions and limitations in the control architecture. The company has pushed the software and hardware hard, yet the underlying system remains too primitive to deliver the level of consistency now required.
That limitation is one reason the Duramax destruction program in this room was paused: the facility itself needed to be upgraded first. Banks sees the AVL-based installation as a move to world-class capability, particularly in the areas of repeatable steady-state testing and emissions measurement. Even so, the absorber, cooling tower, tanks, pumps, framework, and controls shown so far represent only about half of the total build. The project is large, labor-intensive, and far from self-installing, but the intended result is a dyno cell capable of precise, long-duration, emissions-aware engine testing at a level the previous system could not match.