The real tuning target at elevation is air density. Boost pressure by itself can fool you. A truck tuned near sea level may show the same boost number at 5,800 feet, but the turbo may be overspeeding, the charge air may be hotter, manifold air density may be lower, and the engine can end up rich with rising EGT and drive pressure. That is how parts get hurt. With Banks iDash and the AirMouse ambient air sensor, you can see ambient air density, boost air density, and manifold air density instead of guessing from boost alone. That gives you a clean way to tune for changing altitude: if manifold air density drops, pull fuel by the same percentage to keep the air-fuel ratio where the engine wants it. You may give up some peak power, but you avoid chasing a bad boost number and pushing the turbo and engine into failure modes. This setup also logs the data you need to make smart hardware decisions. You can see whether an intercooler, compressor wheel, or inlet location actually improves density, not just pressure. That matters in every Diesel Power Challenge segment, because the truck that survives, stays efficient, and puts down repeatable performance is the truck that stays in the game.
The discussion opens by reframing what Diesel Power Challenge is meant to measure. Although many people reduce it to peak power, dyno numbers, or drag-strip performance, the event is presented as a broader competition in which points are accumulated across multiple segments. A truck may excel on the dyno or in acceleration and still lose ground in fuel-consumption testing or in the cone course, where competitors must maneuver an 11,000-pound trailer through a technical layout. In that sense, the outcome depends not only on the truck, but also on the driver and the team behind it.
That broader view is important to understanding why instrumentation matters. The event is not simply about who can produce the biggest number in one category; it is about how a truck performs as a complete system under different demands. The conversation positions Banks' role in Diesel Power Challenge 2019 around that idea: supplying instrumentation that helps competitors and organizers understand what the trucks are actually doing across all segments.
Banks is introduced as the official instrumentation provider for Diesel Power Challenge 2019, with particular emphasis on the iDash 1.8 system. The host describes it as a highly capable data machine and notes firsthand experience using it on a 2016 Chevy Colorado powered by the 2.8-liter Duramax. Rather than functioning as a simple display, the system is presented as a compact version of the kind of data logging normally associated with an engine dyno cell.
Gale Banks explains that the concept was to take the data logging used in dyno development and put it in the truck. That shift matters because it allows real-world measurement instead of relying on assumptions, conventional gauges, or tuning habits developed at a different location. For competitors, tuners, and data-focused enthusiasts, the value is not just in seeing more channels, but in seeing the right channels-especially those tied directly to air density, airflow, and the engine's actual ability to support fuel and make power safely.
Banks then moves into the core engineering point: horsepower depends on air density. Diesel engines make power by mixing pounds of fuel with pounds of air, and if the engine cannot ingest enough dense air, additional fuel only drives the mixture rich and produces smoke. There is a limit to how much fuel can be used effectively, so making big power requires big air density, defined here as pounds of air per cubic foot entering the cylinders.
He starts with ambient sea-level air density and connects it to the correction factors familiar from dyno testing. A so-called 100 percent day corresponds to about 72.4 pounds of air per 1,000 cubic feet. That baseline changes dramatically with altitude. At high elevation, such as Pikes Peak, the air may be roughly a 60 percent day, meaning about 40 percent of the air density is gone. In naturally aspirated terms, that means roughly 40 percent of the horsepower is gone as well. Turbocharging exists to multiply density, but the key point is that the engine responds to density, not just pressure.
This is why Banks built a gauge around density measurement. Instead of treating boost as the primary indicator of performance potential, he argues that manifold air density is the more meaningful quantity because it reflects the actual mass of air available to support combustion.
That distinction becomes critical when a truck tuned at one elevation is taken somewhere much higher, such as Denver at roughly 5,800 feet. Competitors often arrive with an "at-home" calibration that worked well near their home altitude, only to find that the truck behaves differently in every segment of the competition. The issue is not limited to dyno pulls; it affects towing acceleration, fuel economy, and overall drivability.
Banks explains that trying to maintain the same boost number at high altitude can be a serious mistake. If the turbocharger or compound setup was already near its limit at 1,000 feet, commanding the same boost at 5,800 feet may push the compressors too far to the right on the map. Shaft speed rises, the turbo may overspeed, and the compressor can become inefficient. In that condition, the system may show the same or even higher boost pressure while actually delivering less manifold air density because the air is hotter and less dense.
That creates a chain of failure modes. The hotter charge air may overwhelm the intercooler's ability to remove heat, intake air temperature rises, the engine goes rich, and exhaust gas temperature can climb sharply. Drive pressure also increases as the system works harder to achieve the target boost. The result can range from poor efficiency to catastrophic damage: a fragmented compressor wheel, excessive turbine stress, or even a piston failure. The boost gauge alone does not reveal this. A density measurement does.
The practical tuning recommendation is straightforward. If manifold air density drops by a certain percentage at altitude, fuel should be reduced by the same percentage to preserve the air-fuel ratio that the engine had at home. That means accepting some power loss, but it keeps the engine in a safe operating window instead of chasing a boost number that may destroy hardware.
To support that approach, the conversation introduces the AirMouse, a small ambient-air sensor designed to work with the iDash. Installed in the nose of the vehicle, it measures temperature, absolute pressure, and humidity. Rather than acting as a processor on its own, it supplies environmental data to the gauge so the system can calculate meaningful density values.
Banks describes it as a complete weather-information input for the vehicle. Because it can be moved to different locations, it also helps identify the best place to draw intake air. That is especially relevant because many trucks place the air filter high in the engine compartment near one fender, where underhood heat can reduce density. Banks emphasizes that underhood temperature is the enemy of air density and therefore the enemy of horsepower and torque. The sensor can be used to compare locations and find the best Ram-Air source at the front of the vehicle rather than assuming the existing intake position is optimal.
The discussion includes a practical example using standard-day air density. At 72.4 pounds per 1,000 cubic feet, and assuming a diesel engine operating around a 17:1 air-fuel ratio with a brake specific fuel consumption near 0.42 pounds of fuel per horsepower-hour, the system can estimate that roughly 614 horsepower can be made from 1,000 cubic feet of air. During the demonstration, a simulated ram-air effect increases density enough to raise the predicted horsepower reading from the mid-630 range to about 643 horsepower. Humidity is also shown to matter because water vapor displaces oxygen per cubic foot, reducing density and therefore reducing power potential.
The intended use in Diesel Power Challenge is to equip competitors' trucks with this instrumentation so data can be logged throughout the event. The goal is not merely to display numbers, but to collect information that tuners and competitors can use to improve calibration decisions for all segments of the competition. Banks or his personnel would then help interpret the data so competitors understand what the truck is doing and how to improve it.
One of the strengths of the iDash system is that logging is simple. A run can be recorded with a button press, stored on a micro card, and reviewed afterward. The gauge can also be configured with multiple pages, allowing users to cycle through different screen layouts depending on what they want to monitor. That flexibility makes it useful both as a live instrument and as a post-run analysis tool.
Banks notes that the same setup can even be used to predict horsepower. More broadly, it gives tuners a way to work from measured truth rather than assumptions. He repeatedly frames it as a "truth gauge," meaning a tool that reveals whether a hardware change or calibration change actually improved the truck instead of merely sounding plausible.
A sample data log from the Colorado is used to show the kind of information available. The log includes time, intake manifold air density expressed as a percentage, boost air density, and ambient air density. Banks explains the relationship directly: ambient air density plus boost air density equals manifold air density. That makes it possible to evaluate changes to the turbocharger or intercooler by looking at whether the resulting density improved, not just whether the boost number changed.
Additional channels shown in the log include selected gear, torque-converter lockup status, engine rpm, vehicle speed, oil pressure, intake manifold air temperature, transmission temperature, boost pressure, engine airflow in CFM, and exhaust gas temperature from the stock sensor location, which in this case appears to be after the turbine. All of this comes from the vehicle's OBD-II diagnostic bus plus the AirMouse input. Banks remarks that the available list of displayable values approaches 600 channels, far more than what appears on a factory instrument panel.
He gives a specific development example involving billet compressor wheels for a twin-turbo small-block Chevy in one of Banks' dyno cells. Using density-based analysis, they found that two billet wheel designs produced less density at the same boost than the stock wheels because the outlet temperature was higher. In other words, the billet wheels were less efficient even though they may have looked like an upgrade. That example reinforces the central argument: pressure alone can mislead, while density reveals whether a component is actually doing a better job.
The conversation closes with a new metric Banks says he had just filed a patent on: intercooler efficiency. He distinguishes this from the more common discussion of intercooler effectiveness, which refers to the ability to remove heat. In his view, a complete evaluation must include both heat removal and pressure drop. An intercooler that cools charge air all the way to the cooling medium temperature would be 100 percent effective, but if it also imposed no pressure loss, then it would be 100 percent efficient.
By putting that calculation into the gauge, Banks wants users to determine whether a new intercooler actually improves the system. A thicker or more expensive intercooler may not necessarily be better once both cooling and pressure loss are considered together. This fits the broader development philosophy he describes for turbochargers and intercoolers alike: their job is to add air density, not merely pressure. The useful output is cold pressure, not just pressure.
In that sense, the instrumentation package is presented as a way to make better decisions before and during Diesel Power Challenge. Tuners and calibrators can use manifold air density, ambient conditions, and related channels to adapt trucks for altitude, preserve safe air-fuel ratios, and evaluate hardware honestly. The closing message is not about chasing a single number, but about using measured data to make the truck as effective as possible across the entire competition.