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Updated: April 10, 2026
Originally Published: March 21, 2023
Key Takeaways
- The S13 Integrated Powertrain delivers smooth performance and up to 515 hp with a fully integrated S13 Engine, 14-speed automated manual T14 Transmission and Dual Stage Aftertreatment system.
- Weight-saving innovations make the S13 the lightest 13-liter diesel engine available, boosting payload capacity and efficiency.
- With improved fuel efficiency, a simplified aftertreatment system and readiness for the EPA's 2027 emissions standards, the S13 powertrain is a versatile, sustainable solution for both long-haul and heavy-duty vocational applications.
The International® S13® Integrated Powertrain isn't your momma's International engine. Since its unveiling in 2022, the S13 has taken the commercial trucking industry by storm.
Born from a clean sheet design through global collaboration between International and the Traton Group, the S13 Integrated Powertrain integrates the 12.74L S13 Engine, 14-speed automated manual T14 Transmission and Dual Stage Aftertreatment to provide maximum performance and the most efficient, reliable and sustainable powertrain International has ever produced.
Available for International LT® Series, RH™ Series, HX® Series and HV™ Series models, the S13 has a lot to offer for companies looking to streamline the overall operation of their fleets. To help International truck owners shift their ideas of what's possible for their businesses, we broke down the advantages the S13 Integrated Powertrain provides.
1. Ready for the EPA 2027 Standards
The 2027 EPA standards dramatically reduce allowable nitrogen oxide (NOx) emissions by nearly 80%, making compliance a significant challenge for many engine manufacturers.
But the S13 Integrated Powertrain was designed with the future in mind — which is why it requires only minimal updates to meet these upcoming emissions standards. In fact, approximately 90% of the powertrain carries over from today's model, helping ensure a seamless transition with familiar parts, service tools and technician training.
New enhancements further improve performance and efficiency without adding unnecessary complexity. Variable valve timing optimizes engine performance across a wide range of operating conditions while enabling variable valve braking for stronger engine braking. A new 24-volt electrical architecture — including the alternator, starter and engine controllers — enhances cold-start performance, durability and overall system efficiency while maintaining a 12-volt system for cab and body controls.
The S13 engine, paired with its Dual Stage Aftertreatment system, is so effective at reducing emissions that it eliminates the need for exhaust gas recirculation (EGR) hardware and a diesel oxidation catalyst (DOC). That means fewer components, reduced weight and a simpler system design — all while meeting stringent new emissions requirements.
With its forward-thinking design and smart updates, the S13 Integrated Powertrain is not just compliant with the EPA's 2027 standards — it's built to make the transition easier for your operation while maintaining similar fuel economy, performance and overall weight as today' model.
2. Smooth Operation and Superior Performance
The clean sheet S13 Integrated Powertrain was designed from the ground up without starting from the A26, N13 or other previous International engines. Its three distinct components — engine, transmission and aftertreatment system — were all developed concurrently to ensure maximized compatibility and integration between systems, leading to a smoother and quieter driving experience while improving upon the performance International drivers have come to expect.
The S13 Engine has seven engine rating options and delivers up to 515 hp and 1,850 lb.-ft. of torque at 2,000 revolutions per minute (RPM). Even the most efficient engine rating, code 12BGT, achieves only 400 hp, and full torque is available at only 900 RPM. The engine compression ratio was also improved to 23:1 compared to the 20.5:1 ratio offered by the International A26 engine, equating to more power and better fuel economy.
The S13 Integrated Powertrain also features a wide gear ratio that provides optimal efficiency and performance on both flat roads and hilly terrain. And the new compression release brake ensures secure braking power up to 470 hp when descending, operating at approximately 300 RPM higher than the A26 brake.
Perhaps one of the biggest performance boosters for the S13 Integrated Powertrain is the elimination of the EGR cooler and variable-geometry turbocharger. In a typical engine, the EGR cooler recirculates about 20% of the gas out of the exhaust flow and into the front of the engine, meaning only 80% of produced energy goes to the turbocharger. The absence of the EGR cooler in the S13 allows nearly 100% of energy to flow to the simpler, more reliable fixed-geometry turbocharger, ensuring a more complete fuel burn and delivering more power and improved engine performance.
3. Reduced Weight
The introduction of the new Dual Stage Aftertreatment in the S13 Integrated Powertrain allowed for the removal of the heavy EGR cooler, eliminating 40–50 lbs. from the overall weight of the unit. In addition, the T14 Transmission's planetary gear set eliminates the need for a dedicated reverse gear, allowing for a lightweight, efficiently packaged gearbox. And the single countershaft with helical gears provides overall weight savings without compromising the durability or performance of the transmission.
All of this allows the S13 to be the lightest 13-liter diesel engine on the market, offering a 52 lb. weight reduction compared to the A26 engine.* This weight reduction allows International trucks equipped with the S13 to achieve remarkable payload capacities and improved fuel economy.
4. Increased Fuel Efficiency
Speaking of fuel economy, International LT Series trucks equipped with the S13 Integrated Powertrain lead the on-highway aero category in fuel economy by at least 5%.** To put this into perspective, if an LT Series truck equipped with the S13 was driven 100,000 miles in one year, you would save 550 gallons of fuel, or $2,035 (assuming a price of $3.70/gallon), when compared to driving other comparable on-highway aero models.
Here's how the S13 achieves these impressive fuel savings:
- The S13 Engine operates at low RPMs and high torque, resulting in fewer fuel injections and less fuel consumed.
- A new cylinder and piston head with maximum cooling properties were designed, along with a new double overhead camshaft (DOHC) featuring an integrated compression release brake assembly and parallel valve pattern. Combined, these result in reduced parasitic losses.
- The engine was converted from a 10-blade to a six-blade fan to increase efficiency.
- A higher compression ratio, a higher air-to-fuel ratio, a new peak cylinder pressure of 250 bars, longer fuel burn duration, extreme XPI injectors that operate at lower pressures and adapt for the quick release of fuel, and the reversed rotational direction of the turbine wheel all contribute to improved combustion efficiency.
- Friction within the powertrain was reduced by improving the materials used on liners, rings, coatings and bearings, as well as using a single countershaft geartrain design for the T14 Transmission rather than a dual countershaft.
- The high-pressure fuel pump was designed to operate at only 1,800 bars of pressure compared to the 2,500 bars needed to operate the fuel pump in the A26, a 28% decrease that means less energy is needed to pressurize the fuel and lower parasitic losses.
- Pumping losses were further improved by optimizing the size and flow rate of the coolant pump, ensuring efficient air passage through the intake and exhaust manifolds, and by using a DOHC with separate intake and exhaust cams.
5. 14-Speed Overdrive Transmission with Shift-On-The-Fly Capabilities
The T14 is a 14-speed, fully automated manual transmission and International's first commercial transmission to go to market. Thanks to the holistic design behind the S13 Integrated Powertrain, the transmission's electronic clutch actuator works in sync with the S13 Engine, resulting in gear shifting that is perfectly matched to engine revolutions for a faster, smoother shifting experience. Drivers also get the benefit of a quicker-accelerating package in a downsped configuration thanks to the T14 Transmission's overdrive 14th gear and direct drive 13th gear being optimized to deliver peak fuel economy during typical load.
The T14 was designed to not consume air during complicated maneuvers, such as backing a truck into tight spaces, which means drivers do not need to stop and let air recharge. And the transmission also uses an integrated oil-to-water coolant system that optimizes temperature regulation in hot and cold environments, allowing the T14 to achieve an unlimited gross combination weight rating for on-highway applications.
Two crawler gears on the transmission offer heavy-load stability and low-speed maneuvering capabilities as well as consistent performance when carrying heavy loads requiring lower rear axle ratios. Plus, Eco, Performance and Performance+ modes allow drivers to shift on the fly, and options for downhill speed control, eco-coast and creep modes enhance driving performance even further.
6. Easily Serviced and Sustainable Dual Stage Aftertreatment
According to International, the S13 Engine will be the last internal combustion engine it will ever produce as it shifts its focus to investing in and developing carbon-neutral technologies. However, until electric, zero-emissions vehicles are widely available, the S13 Integrated Powertrain is compliant with the EPA's 2027 standards and designed to be as sustainable as possible. And we have the new Dual Stage Aftertreatment system to thank for it.
Difficulties with heavy-duty emission-control systems such as clogged diesel particulate filters, EGR failures and sensor malfunctions cost fleet managers time and money. The Dual Stage Aftertreatment was developed alongside the selective catalytic reduction-based S13 Engine to solve these problems through reduced complexity, increased serviceability and improved emissions control.
The removal of EGR hardware from the S13 Engine simplifies the system architecture and supports cleaner, more efficient combustion. It also means much less soot and particulate matter are generated since the engine can burn fuel more effectively. In fact, the reduction in soot buildup is so great it allows the powertrain to operate at lower temperatures, eliminating the need for a DOC and active diesel particulate filter (DPF) regeneration cycles in the aftertreatment system. Instead, passive regeneration cleans out the DPF in most conditions.
However, as soot production is reduced, NOx emissions typically increase. To keep NOx emissions at bay, the Dual Stage Aftertreatment breaks down NOx using dual diesel exhaust fluid (DEF) injectors to distribute a first dose of DEF in the evaporator tube after exhaust flows through the turbocharger and a second dose in the aftertreatment container. As a result, the DPF only needs to be serviced every 650,000 miles.
All of this combined makes the Dual Stage Aftertreatment system a simple, reliable solution that's easily serviceable when, and if, service is needed.
7. Power Take-Off (PTO) Options for Heavy-Duty Applications
The S13 Integrated Powertrain is now available in HX520, HX620, HV515 and HV615 model trucks, expanding its capabilities from long haul and regional haul to vocational applications. The HX Series and HV Series are ideal for severe-duty jobs in construction, dump, refuse, towing and logging, meaning they need a powertrain that can maintain speed and power, no matter the load.
To do just that, International severe-duty trucks equipped with the S13 Integrated Powertrain will come with the option of rear engine PTO, front engine PTO, and single and dual output transmission PTOs. These PTOs will direct power produced by gear rotation in the transmission and transfer it to mounted equipment, such as a dump body, cement mixer or crane, to allow them to function. The optional PTOs will be installed on the S13 in the factory and carry the same warranty as the T14 Transmission.
To equip the S13 Integrated Powertrain even further for vocational applications, the T14 Transmission features vocational-specific drive modes such as off-road, manual and paver. Plus, the T14's deep crawler gears provide the slow-speed maneuverability and startability needed on jobsites.
Explore Our S13 Integrated Powertrain Inventory
Rush Truck Centers is excited to offer the S13 Integrated Powertrain in International trucks. View our available inventory of International trucks with the S13 Integrated Powertrain, or contact an International dealership near you for more information.
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*When paired with the 12-speed overdrive Eaton Endurance HD automated transmission.
**The International® LT® with S13® Integrated Powertrain was tested head-to-head using TMC Type IV testing methodology against competitive on-highway aero models with comparable specifications: Freightliner Cascadia AeroX DD15, Kenworth T680 MX13, Volvo VNL760 D13. Testing proved the International LT with S13 Integrated Powertrain to be at least 5% more fuel efficient than these models. The International LT with S13 Integrated Powertrain uses up to 3.5% more DEF per gallon of fuel compared to comparable on-highway aerodynamic models.
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