If there is anyone you can count on when it comes to delving into the ins and outs of a Duramax engine, it is Gale Banks. Banks Power is a thriving Duramax-happy company that can get you from mild to wild in a hurry, and burn clean while doing it. In his latest video, Mr. Banks dissects a new, 2024 model 6.6-liter L5P Duramax engine and compares it side-by-side to the 2023 model. If you recall, Gale did a series called “Killing a Duramax” and he was never able to blow apart the engine.

The 2024 Duramax appears to be even more bulletproof than the 2023. Gale starts by saying, “this is data that you won’t find on a spec sheet!” This new engine will be available in the 2024 Chevrolet Silverado and GMC Sierra HD trucks and will boast 470 horsepower and 975 lb-ft of torque which is a step above the older ’23 unit.

Better Pistons Make A Better Engine

The engine has undergone several enhancements, including the introduction of a new turbocharger, pistons with a tapered bowl design, cylinder heads with enhanced cooling jackets, higher-flow injectors to facilitate greater fuel injection pressure, reinforced fuel rails to withstand the increased pressure, and advancements with glow plugs. We also learn about the L5P Duramax engine utilizing improved engine braking through a more potent turbo vane actuator, upgraded valve springs, and the integration of the latest Engine Control Module featuring the new Global B architecture.

The improved piston design aids with combustion and emissions.

After attempting to break the 2023 engine, Banks eclipsed 1,000 horsepower and the bottom end held together quite nicely. Banks notes the 2024 engine bottom-end parts are the same as the 2024 and looks to be just as bulletproof. However, there was a significant change, with the pistons. “What you’re looking for when it comes to pistons is combustion efficiency and diminished emissions,” Banks said. “If you can cut emissions in the engine, you’re taking the strain off of the emissions systems inevitably allowing them to live longer.”

Banks explains that the new 2024 L5P Duramax engine boasts pistons with a more “pointed” area in the center of the piston which nearly mimics the racing-style pistons they [Banks] designed years ago. This design is the perfect mixture of a lean area and a rich area of the piston which results in fewer pollutants. After all, that is what they [GM] are after.

Sealed Up Heads

When laying the 2023 and 2024 L5P Duramax head gasket side-by-side, they look identical. “On the earlier model, there are four layers to the MLS gasket,” Banks said. “However, for 2024, there are three uniform layers and one thicker one. The guys at GM have come up with a new and improved design that will seal better and last longer with high unit loading.”

High-Pressure Fuel Pump

The new high-pressure fuel pump on the 2024 Duramax features a cam ring with a lobe inside that spins and operates much like a camshaft and lifter. “These new pumps have a pumping capacity of 2,200 bar,” Banks said. “That is 32,000 psi. The 2023, however, was only 2,000 bar and 29,000 psi.” What is the purpose of this boost in pressure capability? Per Banks, this higher pressure allows the engine to reach the desired fuel amount through smaller holes. This will atomize better and inevitably refine this process which will result in improving the combustion process.

High-Pressure Fuel Rails

The 2023 engine included a fuel rail that is 24.5mm thick. The 2024 features a thicker, 26.3mm unit. Why? Again, per Banks, “I guarantee this is because of wall thickness to bump the safety margin for that extra 3,000 psi.”

With each engine side-by-side, they look virtually identical. However, the 2024 is more durable. “They have revised the interior structure of the water jacket area, but what is really apparent is the free length of the exhaust valve spring,” Banks said. “In order to improve exhaust braking, they’ve beefed up the exhaust valve springs.” If you up the exhaust back pressure too much, you can float the valves. This is the result of wanting to improve the exhaust braking and the valves to support that.”

Cylinder Heads And Valve Springs

There have been complaints in the past from drivers that they are unable to realize when the exhaust brake is actually in use. But now with the added seat pressure and tougher springs, they should feel it more now.

Brand New Turbocharger Design

New for 2024, the L5P Duramax engine received an upgraded turbo. In comparison with the 2023 version, they look very similar. But there are some differences. The turbine housing bore is a single millimeter larger in diameter and the turbine wheel has gone from 11 blades to 10. “By going to the 10 blade, they’ve created a larger mass flow area for the exhaust to escape,” Banks said.

“Another major difference I can see is the variable control actuator. VGT turbos require a calibration control and for 2024, it is a new design. While they are both BorgWarner pieces, the ’24 is an enhanced mechanism. It is quicker, more powerful, and as a result, you can control the speed of the turbocharger more quickly.” With a better-designed actuator on board, this should improve fuel efficiency, throttle response, and reduce emissions, etc.

Banks Power has its hands on a 2024 and plans on putting this through as many tests, if not more, as they did with the 2023 model that reached the 1,000 horsepower threshold.