Product description
T3 Exhaust Manifold for 24V Cummins 1998.5–2002 | 3-Piece Expansion Design | CARB Exempt
The Diesel Power Source® T3 exhaust manifold for 1998.5–2002 Dodge Ram 2500 and 3500 trucks with the 5.9L 24-valve Cummins engine is a direct bolt-on replacement that flows 23% more than the factory manifold while typically adding 10–18 HP on a 400 HP truck. This 3-piece expansion joint design is cast from nickel-laced ductile iron, CFD designed and flow-tested, and includes three pre-tapped ports for pyrometer and boost pressure fittings. It replaces OEM part numbers 5014170AC, 5014170AD, 5014170AA, 5014170AB, and 3937187.
This manifold is CARB exempt with an Executive Order (EO) number, making it legal for use in California.
Why the Stock 24V Manifold Fails
The factory 24V Cummins exhaust manifold is a single-piece casting that cracks and warps over time from repeated thermal cycling. The rigid design cannot flex with temperature changes, so cracks develop at stress points, exhaust leaks form, and gaskets fail. Cracked manifolds rob the turbo of exhaust energy, raise EGTs, and create an exhaust smell in the cab. The DPS 3-piece expansion joint design solves this by allowing each section to expand and contract independently, absorbing thermal stress instead of transferring it to the casting.
Dedicated 24V Round Port Casting
Nearly every competitor manifold on the market uses the same casting mold for both 12V and 24V applications. They cast using a 12V rectangular port design and then machine the ports to fit the 24V round port head. This creates smaller, restricted port openings and poor exhaust flow transitions.
The DPS 24V manifold uses a dedicated round port mold designed specifically for the 24V head. The port geometry is optimized from the head flange through the runners to the collector, delivering unobstructed flow that is not possible with machined-down 12V castings. This is more expensive to manufacture, but the result is measurably better flow and performance.
Why Runner Size Matters: Bigger Is Not Always Better
Some competitor manifolds advertise oversized runners or large tube designs. While this sounds appealing, runners that are too large actually slow exhaust gas velocity. The exhaust then has to re-accelerate as it bottlenecks through the turbo flange, causing a loss in both horsepower and turbo spool-up. DPS has tested competitor manifolds with oversized runners that decreased horsepower by 40 HP on a 400 HP truck.
The DPS manifold uses CFD-tested runner geometry that maintains exhaust velocity from the ports through the collector while flowing 23% more volume than stock. The runners are sized to work with the turbo, not fight it. Additionally, the DPS design balances flow across all six cylinders so that end-port EGTs are much closer to center-port EGTs, reducing the hot spots that cause manifold cracking.
**DOES NOT INCLUDE MANIFOLD HARDWARE/GASKETS**
