Diesel Power Source® ISX15 / X15 exhaust manifolds replace the factory manifold on 2010-2025 Cummins ISX15 and X15 engines. The factory manifold uses ring seals between its three sections, and those seals frequently fail and leak. A DPS manifold is three sections pressed together with a metal-to-metal fit, cast from High Silicon Molybdenum Ductile iron (HSMD), CFD tested, and pressure-tested before it ships. It flows approximately 22% more than the factory manifold and typically lowers EGTs by approximately 75-100°F.
About 22% More Flow
CFD tested against the factory manifold
75-100°F Lower EGTs
Approximate, and most noticeable under sustained load
No Ring Seals
Press-fit joints replace the factory seals that fail and leak
Matched by ESN
Your engine serial number confirms the manifold before it ships
Why Factory ISX15 / X15 Manifolds Leak, and What DPS Changes
Factory Ring Seals Fail
The factory manifold and the DPS manifold are both 3-piece assemblies: a front section, a center turbo-mount section, and a rear section. The factory design seals those joints with ring seals, and the ring seals frequently fail and leak.
Press-Fit Joints
DPS sections are hydraulically pressed together with an interference fit, so there is no consumable seal to wear out. The inner piece heats faster and expands into the outer piece, which makes the joint tighter as temperature rises.
HSMD Iron
HSMD is rated approximately 200°F higher than traditional cast iron and holds stable clamping pressure through heat cycles. Stainless steel expands and contracts about twice as much as ductile iron, which breaks bolts and destroys gaskets on a long six-cylinder engine.
CFD-Tested Flow
Lower drive pressure lets the turbo reach boost sooner, and customers typically report spool about 200 RPM earlier on the ISX15. EGT reductions are most noticeable under sustained load. The turbo is the primary EGT bottleneck, so results depend on the whole system.
Fitment
- Cummins ISX15 / X15, 2010-2025
- CM871, CM2250, CM2350, and CM2450 platforms
- EGR manifold: trucks with the EGR system in place
- Non-EGR and T6 manifolds: trucks that have already been deleted
- An engine serial number (ESN) is required on every ISX15 / X15 order. Verify your ESN with DPS before ordering.
Install Notes
- Torque the turbo to the manifold at 48 ft-lbs. Follow the install instructions for manifold-to-head torque.
- After about 100 miles, re-torque all manifold and turbo bolts while the engine is warm. Wear gloves.
- EGR manifold: connect the bellows pipe to the EGR system.
- Non-EGR manifold: attach the ECU pressure sensor line to the pre-installed fitting.
- Always use new gaskets. DPS does not recommend anti-seize on manifold hardware.
- ISX15 / X15 manifolds have pre-tapped 1/8-inch and 1/4-inch NPT ports.
- Warranty under the Diesel Power Source® PMA: manifolds 1 year. Registration within 14 days of purchase is required.
Hardware and Gasket Kits
Bolt and spacer kits use OEM-style fastening, which many ISX15 / X15 owners prefer. Most customers order the manifold, the gaskets, and the hardware together.
Related categories: ISX15 / X15 Performance | HE400VG VGT Turbos | S400 Turbos | ISX15 / X15 Compound Turbo Kit | 6.7 Cummins Manifolds | All Exhaust Manifolds. Questions on fitment? Call 801-930-8404 or email sales@dieselpowersource.com. Free shipping on orders over $350.
Cummins is a registered trademark of Cummins Inc. Diesel Power Source® is not affiliated with Cummins Inc.
