High-rpm diesel power is not just about adding more fuel. The real limit is whether the pump can hold rail pressure and whether the injectors can get that fuel into the cylinder fast enough. Once a stock CP3 runs out of flow, rail pressure falls off, injection stretches across too much crank angle, and combustion keeps going too late in the cycle. That drives up exhaust temperature, wastes fuel as smoke, and leaves power on the table. Here the fix is a 10mm stroker CP3 and higher-speed S&S injectors. The larger-stroke pump keeps fuel delivery and rail pressure up at engine speeds where the stock pump is already flattening out. The injectors shorten on-time for the same fuel delivery, so more of the burn happens where it can make cylinder pressure instead of heat in the exhaust. That is the whole game at elevated rpm: maintain pressure, shorten injection duration, and finish the burn in the cylinder. Do that right and you gain usable power, better combustion efficiency, lower EGT, and less smoke.
The video opens with the context from Banks' monster truck engine build. In the previous round of testing, the Duramax made 666 horsepower at 5,000 rpm, but the combination ran out of rail pressure. That shortfall led the team to S&S in Indiana, a company Banks describes as highly specialized in diesel fuel-injection pumps, injectors, and related hardware. S&S supplied upgraded pumps and injectors intended to support higher engine speed and improved fuel delivery.
The goal is not simply to add more fuel. The upgraded system is meant to maintain rail pressure to 5,500 rpm and to shorten injector on-time, or the crank-angle window required to deliver a given amount of fuel. That matters because faster fuel delivery improves power potential, combustion efficiency, exhaust gas temperature control, and smoke reduction. In a high-rpm diesel application, those factors are tightly linked.
S&S starts with the Bosch CP3 pump as the foundation for its build. Banks explains that the stock CP3 is compromised in factory form, particularly when engine speed rises. The stock pump uses an 8.2 mm stroke, while the S&S unit shown here is a 10 mm stroker. S&S also offers versions up to 12 mm, but Banks identifies the 10 mm pump as the sweet spot for this project.
Physically, the pump still resembles a stock CP3, but its operating range is very different. A stock CP3 reaches its practical limit at about 3,500 rpm. Beyond that point, it plateaus and no longer delivers additional fuel as rpm increases. If pushed far enough, output can actually decline because the pump begins to hurt itself. That behavior makes the stock unit a major restriction in a high-speed diesel build.
Banks gives specific flow and efficiency figures for the stock CP3. At 3,000 rpm, it delivers about 187 liters per hour and operates at roughly 95 percent efficiency. At 5,500 rpm, flow rises only slightly to 211 liters per hour, while efficiency falls sharply to 59 percent.
Converted to mass flow, that is about 396 pounds of fuel per hour. In theory, that amount of fuel is enough to support 942 horsepower, but not all of it reaches the cylinders as usable power. Some fuel is returned through the system to help cool components such as the nozzles, and that return can be as much as 20 percent. Using a practical estimate, Banks says a stock CP3 can support around 800 horsepower. Even then, the real limitation is rpm. Once the pump is effectively done by 3,500 rpm, revving higher becomes increasingly pointless.
The S&S 10 mm stroker pump changes that operating envelope substantially. Banks says this pump will run to 5,500 rpm and can go beyond that, which means it does not require a belt-drive conversion just to survive at the target speed. It can remain in the engine valley in the stock location, although a belt drive may still be useful if packaging changes are needed for custom intake or manifold work. Importantly, the pump can be driven one-to-one with crankshaft speed.
This matters because diesel combustion has a natural upper-speed sweet spot of roughly 5,500 rpm. Beyond that, the time required for combustion becomes too long relative to engine speed. Banks emphasizes the crank-angle issue: fuel must burn in the cylinder at the proper point in the cycle, not continue burning after the exhaust valve opens. If combustion extends too far into the exhaust event, energy is wasted as heat and flame in the exhaust stream rather than being converted into useful work at the piston.
The upgraded pump also raises available rail pressure. The stock CP3 will reach about 1,800 bar, while the S&S pump is rated for 2,000 bar continuous rail pressure and can go beyond 2,000 bar. Banks says it can reach 2,500 bar intermittently for short bursts of power. Higher pressure helps force fuel into the cylinder in a smaller crank-angle window, which is exactly what a high-rpm diesel needs.
The flow numbers show how dramatic the difference is. At 3,000 rpm, the S&S stroker increases output from 187 to 238 liters per hour. At 5,500 rpm, it delivers 410 liters per hour instead of 211. Efficiency improves as well: the pump is 100 percent efficient at 3,000 rpm and still 91 percent efficient at 5,500 rpm. That corresponds to about 769 pounds of fuel per hour, enough in theory for 1,830 horsepower. After accounting for returned fuel, Banks estimates the practical usable figure is close to 1,600 horsepower worth of fuel from a single pump.
For this engine, Banks is running two of these pumps. After subtracting return fuel, he says the system should have enough fuel to exceed 3,000 horsepower. That is more than he actually wants for a monster truck engine, since the engine must run hard and survive for long periods. His preferred range is more like 1,250 to 1,500 horsepower, with 1,250 to 1,300 sounding especially appropriate for the truck. The twin-pump arrangement therefore provides substantial overhead rather than operating at the edge.
Supplying the pumps alone is not enough; the rest of the fuel system must also be opened up to carry the added volume. Banks notes that the outlet fittings feeding the injectors are being enlarged, along with the fittings on the feed line into the rails and the cross-feed line between rails. The emphasis is on increasing the internal size of the fittings rather than changing the line itself.
That detail reflects a common high-flow bottleneck. Even when the main lines appear adequate, restrictive fittings can limit the system. Since the project is now designed around twin high-capacity pumps and elevated rail pressure, those internal restrictions must be addressed so the rails and injectors can actually receive the available fuel.
S&S also supplied a set of injectors built from Bosch hardware. Banks shows one injector and points out its basic features, including the electrical connection, fuel inlet, and protective boot over the nozzle. The important changes are internal. According to Banks, S&S improves the speed at which the injector delivers fuel, meaning it shortens the on-time required to achieve a given fuel quantity.
S&S includes a detailed calibration chart covering multiple rail pressures and injector on-times. That data can be entered directly into the ECU so the engine calibration matches the injectors as delivered. For a controlled high-performance diesel build, that information is critical. It allows the tuner to command the correct pulse widths rather than guessing at how the modified injectors behave.
Banks compares these injectors with the 1350-flow-rate nozzles previously used. The new injectors are also 1350 flow rate, but they reduce on-time for the same fuel delivery by about 14 percent at lower flows and shorter on-times, and by about 8.5 percent at higher flows and longer on-times. In other words, they do not merely flow a lot of fuel; they deliver it faster.
Banks spends considerable time explaining why shorter injector on-time matters. In a diesel, injection begins before the piston reaches top dead center, and combustion begins almost immediately after a very small ignition delay. Depending on speed, load, and power level, combustion may begin 5, 10, or 20 degrees before top dead center. The objective is to achieve peak cylinder pressure at the correct point after the piston passes top dead center and starts down the bore on the power stroke.
Once peak cylinder pressure has been reached and the piston is moving down, the injector needs to shut off before fuel is sprayed into gases that are already expanding and cooling. Banks refers to the old diesel phrase "injecting into the cold burn." Fuel delivered too late does little useful work and instead drives exhaust gas temperature higher because combustion is still occurring when the exhaust valve opens.
That is why quick injectors with high flow capability are essential for high-rpm diesel operation. As rpm rises, the time available for each degree of crank rotation becomes shorter and shorter. The combustion process still needs a certain crank-angle span, but the real-time window shrinks. To keep combustion in the right place, the injectors must have the flow capacity and calibration to deliver the required fuel in less time. Banks says 1350s are already substantial in terms of flow capability, and with the right injector behavior they improve combustion efficiency, add power, reduce EGT, and cut smoke. Smoke is simply unburned fuel, so reducing it means more of the injected fuel is doing useful work in the cylinder instead of leaving the tailpipe as wasted energy.
Banks closes by highlighting two S&S pump modifications that support both drivability and top-end performance. One is an improved flow-control valve called X2. The other is a high-speed package referred to as the HS mod, which includes improved inlet valves and related changes.
Those features matter because a very large pump still has to behave properly at idle and across the full operating range. The combination is intended to provide high capacity without sacrificing control at low flow or responsiveness at high flow. Banks' conclusion is that S&S has delivered a pump and injector package capable of supporting the engine's rpm target, maintaining rail pressure, and improving combustion timing where it matters most.