The real problem with most inline tuners is simple: they intercept one or two signals and add fuel with no idea what the truck is doing. That works right up until heat climbs, altitude changes, a regen starts, or the transmission is in the middle of a shift. On the Ford 6.7L, that kind of blind tuning can cost power, create harsh behavior, and put the engine and transmission in a tug-of-war with the factory controls. The Banks Derringer Tuner takes a different approach. It communicates through OBD-II, reads live vehicle data, and adjusts added power in real time. That lets it manage fueling and boost based on actual operating conditions, roll power in with pedal input, limit added power when temperatures climb, account for altitude, recognize regen, and back off during shifts through TransCommand logic. It also uses ActiveSafety to return the truck to stock power if a fault is detected. That’s why Derringer stands apart from the usual fuel-only box. It makes stronger, broader usable power, but more importantly, it delivers that power with situational awareness. For a working Super Duty, that means better towing and passing response without giving up the safeguards the truck needs under load.
Gale Banks opens with the conclusion first: for the Ford 6.7L Super Duty, he considers the Banks Derringer the only inline tuner worth considering. His central claim is that the Derringer is the only "smart" inline tuner in the group because it connects through OBD, allowing it to protect the truck while still delivering the advertised power. He frames the comparison around safety, repeatable performance, and warranty friendliness rather than inflated marketing numbers.
To support that claim, Banks says the company bought competing tuners and tested them on the same truck, on the same day, in the same weather, on the same dyno, and over the same road with the same driver. The competitors discussed are aFe, AG Diesel, TS Performance, and Stealth. He also notes that Stealth, Doctor Performance, and Diesel Dominator are effectively the same hardware with different stickers, so only one of those was tested.
Banks emphasizes that the factory rating of 440 horsepower and 925 lb-ft for the 2017-2019 Ford 6.7L Super Duty is a flywheel number, not what actually reaches the pavement. He focuses instead on wheel output, because that is what matters in real driving. On the dyno, the stock truck produced 389 horsepower at the road surface, with peak power occurring a little after 2,800 rpm.
He also defines the engine's practical operating range under wide-open throttle. According to his explanation, the downshift point is about 2,150 rpm and the upshift point is about 3,150 rpm. That means the useful performance window is the middle of that range, not just the single highest peak number. This becomes important later when he discusses area under the curve and the ability to hold power all the way to the shift point.
With the Derringer paired to an iDash front end such as the DataMonster or SuperGauge, Banks reports a peak of 443 wheel horsepower. That represents a 54-horsepower peak-to-peak gain over stock, with a best gain of 59 horsepower. For buyers using the Derringer with only the switch and no iDash, he reports 432 wheel horsepower, a 43-horsepower peak-to-peak gain, and a 44-horsepower best gain.
The aFe Scorcher, which modifies both fuel and air, reached a 28-horsepower peak-to-peak gain and a 33-horsepower best gain. TS Performance MP-8, which Banks characterizes as a fuel-only approach, reached 414 horsepower, for a 25-horsepower peak-to-peak gain and a 26-horsepower best gain. Stealth reached 412 horsepower, for a 23-horsepower gain and a 24-horsepower best gain. AG Diesel came in at 401 horsepower, which Banks describes as only a 12-horsepower gain with a 14-horsepower best gain.
Banks argues that the Derringer's advantage is not just the highest peak, but the shape of the curve. He says Banks deliberately broadens the peak so power starts building before 2,800 rpm and carries nearly to 3,000 rpm. That broader plateau creates more area under the curve, which means the truck continues pulling hard right up to the upshift instead of falling off sharply near 3,000 rpm like the competing units.
Because diesel performance is defined as much by torque as horsepower, Banks then shifts to wheel torque. Stock output measured 829 lb-ft at the road surface. With the Derringer and iDash, he reports 892 lb-ft, a 63 lb-ft peak-to-peak gain and a 106 lb-ft best gain. With the switch-only Derringer, output was 866 lb-ft, a 37 lb-ft peak-to-peak gain and a 79 lb-ft best gain.
The aFe Scorcher reached 862 lb-ft, for a 33 lb-ft peak-to-peak gain and a 64 lb-ft best gain. TS MP-8 reached 867 lb-ft, for a 38 lb-ft peak-to-peak gain and a 50 lb-ft best gain. Stealth reached 863 lb-ft, for a 34 lb-ft peak-to-peak gain and a 43 lb-ft best gain. AG Diesel reached 850 lb-ft, for a 21 lb-ft peak-to-peak gain and a 25 lb-ft best gain.
Banks places special emphasis on torque rise while lugging a grade. He explains that when the truck is pulling hard and rpm begins to drop from the horsepower peak, torque should rise to help the engine hold the current gear. That matters for towing because a forced downshift raises rpm and fuel consumption at exactly the point where efficiency is already poor. In his telling, the Derringer's torque curve dominates this lugging region, helping the truck stay in the efficient part of the engine map instead of backshifting.
Banks divides the tested products into two categories. Stealth, AG Diesel, and TS Performance are described as simple fuel-rail-pressure interceptors that alter one sensor signal and command more fuel. He calls them "Johnny one-note" devices because they keep doing the same thing regardless of operating conditions. The aFe unit also modifies manifold absolute pressure in addition to fuel rail pressure, so it adds both fuel and air, but Banks says that is still far short of what the Derringer does.
The key distinction, he says, is the Derringer's OBD connection. That link gives the tuner access to the truck's ECU data so it can tune dynamically rather than blindly adding fuel. Banks calls this adaptive tuning and says the Derringer makes adjustments 250 times per second. He describes that as situational awareness for the truck.
According to Banks, the Derringer reads or calculates fuel rail pressure, manifold absolute pressure, engine rpm, vehicle speed, engine coolant temperature, accelerator pedal position, ambient air pressure, torque-converter lock status, DPF regen status, transmission gear commanded, current gear position, current gear ratio, commanded gear ratio, calculated engine load, exhaust manifold temperature, speed rate of change, transmission slip rpm, and air-fuel ratio. Because it has access to those parameters, he argues that it can add power while still protecting the engine and transmission.
Banks says the Derringer actively manages exhaust gas temperature rather than simply adding fuel until the factory intervenes. On the Ford 6.7L, he states that the engine begins limiting power at 1,450 degrees F turbine-inlet EGT in order to stay below a 1,500-degree maximum. Because the Derringer knows the temperature, it also starts limiting its added power at 1,450 degrees, mirroring the factory strategy.
Altitude compensation is another major point in his argument. At high elevation, ambient air pressure drops, so a tuner that only adds fuel will drive EGT upward and trigger the ECU to pull power back. Banks says the Derringer senses ambient pressure and controls the turbocharger to maintain added boost and power as altitude increases. He contrasts that with the other inline tuners, which he says continue adding fuel without understanding the thinner air, creating a tug-of-war with the ECU as the tuner adds fuel and the ECU repeatedly derates to cool the engine.
He also says the Derringer monitors DPF regeneration, while the competing boxes do not even know a regen event is occurring. Accelerator pedal position is used to roll in added power progressively, which he says improves part-throttle fuel economy while still allowing maximum output when the driver requests it. Coolant temperature is also part of the strategy: no added power below 120 degrees F, ramp-in between 120 and 150 degrees, full added power above 150 degrees, reduction beginning at 230 degrees, and complete removal of added power above 240 degrees. Transmission slip is monitored as well, and the Derringer reduces added power if excessive slip is detected.
Banks argues that fuel economy cannot improve if the engine is run at the same air-fuel ratio as stock or richer than stock. He presents stock full-power air-fuel ratio as 18:1. The Derringer, he says, runs at 19:1 by supplying more air than stock, making it the only tested inline tuner to run leaner than stock at full power. By contrast, aFe and AG Diesel are said to remain at 18:1, while TS MP-8 and Stealth run at 17:1. He also mentions flash programmers tested separately, saying they commonly ran as rich as 16:1 at peak power or torque, which raises EGT.
Boost figures are presented alongside those ratios. Stock boost is given as 24 psi. The flash programmers tested were around 27 psi, aFe was at 28 psi, and the Banks Derringer reached 30 psi. Banks' point is that boost alone is not enough; the combination of air and fuel must remain controlled so the engine does not run excessively rich and hot.
For towing, he says the Derringer includes logic that allows 30 seconds of wide-open throttle on Sport level before transitioning to the recommended sustained trailer-towing power level. The purpose is to avoid excessive heat during long pulls. He contrasts this with flash tuning, where the engine is permanently recalibrated to run hotter and richer, causing repeated heat-up and derate cycles under load. He also notes that flash tuning leaves evidence in the ECU even if removed, whereas an inline tuner like the Derringer can be removed without leaving that trace.
Banks says the Derringer uses engine and transmission data to improve shift behavior and protect the transmission. Because it knows when a shift is occurring, it can modulate added power during those events. Competing inline tuners, lacking OBD data, continue adding power regardless of shift timing, which he says can increase transmission slip and torque-converter clutch slip.
He then focuses on active safety. According to Banks, the Derringer is the only tuner in the comparison with a watchdog circuit and active bypass relays. Under normal operation, signals pass through the relays, are processed by the Derringer CPU, and then sent to the truck's ECU. If the Derringer loses power or detects a fault, it enters failsafe mode and smoothly returns the truck to stock power. He says the system monitors itself more than 50 times per second.
To demonstrate the difference, Banks performs road tests where he interrupts power to each tuner during acceleration. With the Stealth-style one-wire box, cutting power caused a dead accelerator pedal, multiple trouble codes, engine shutdown, and a no-restart condition until codes were cleared. He describes codes related to fuel rail, injector, and glow systems. With the aFe unit, cutting power during a passing-style acceleration caused a surge, engine knock, loss of steering assist as the engine died, and a complete stop. By contrast, when he repeated the test with the Derringer installed, the truck continued running on stock power when the unit was switched off, then resumed added power when switched back on.
Banks describes two ways to control the Derringer. The first is a simple switch with three positions: Stock, Plus, and Sport. Stock turns the tuner off, Plus provides about 60 percent of the available added torque and horsepower, and Sport provides 100 percent. The second method uses an iDash DataMonster or SuperGauge. When connected, the iDash recognizes the Derringer and displays a control screen with multiple levels. Banks describes Stock plus levels two through six, with each step adding roughly 10 horsepower and 20 lb-ft, and says these levels can be adjusted while driving.
The iDash also exposes data the truck does not normally show. During DPF regeneration, for example, the display flashes a regen indication. Banks demonstrates a pull where the power-added bar rises under throttle, while boost, fuel rail pressure, and EGT are displayed. In his example, road speed is near 30 mph, EGT is about 860 degrees F, and boost is about 23.3 psi. He also highlights manifold air density, saying it is more meaningful than boost because it accounts for pressure, temperature, and humidity. He cites a reading of about 233 percent of a normal day and says this metric reflects the combined performance of the intake, Ram-Air system, turbocharging, and intercooling. Additional displayed values include ambient pressure, ambient temperature, relative humidity, engine coolant temperature, engine oil temperature, and transmission temperature.
Finally, Banks compares cost per horsepower gained. AG Diesel is listed at $408, which he calculates as $30.10 per horsepower. Stealth is listed at $550, or $23 per horsepower. TS MP-8 is listed at $399, or $15.70 per horsepower, though he criticizes TS product reliability and says units they ordered did not work out of the box. The aFe Scorcher is listed at $474, or $14.50 per horsepower. The Derringer with iDash SuperGauge is listed at $769, which he calculates as $13.03 per horsepower while still outperforming the others. The Derringer with the switch is listed at $499, or $11.34 per horsepower gained. His conclusion is that, on power, efficiency, reliability, safety, and removability, no other tuner in the comparison matches the Derringer.