1998.5-2002 Dodge 5.9L Cummins Compound Turbo Kits

Compound turbos on the 1998.5-2002 RAM 5.9L Cummins

From the factory, the 24-valve uses one wastegated Holset: the HX35W on 1998.5-1999 trucks and manual trucks, the HY35W on 2000-2002 automatics. That turbo is adequate at stock power. Once injectors and a tuner go on, it becomes the ceiling, and compound kits are one way past it. Several builders catalog compound setups for this engine, ATS among them. The rule is the same as for any turbo: match the setup to your fueling and tuning, not to a horsepower number.

Before you go compound

• Fuel first. The VP44 relies on supply fuel for cooling and lubrication. The order is fuel pressure gauge, upgraded or relocated lift pump, then added power.
• Transmission. The 47RE automatic is rated at about 450 lb-ft of input torque, and automatic trucks hit that limit first. The NV4500 is rated at 460 lb-ft max input and the NV5600 at 550 lb-ft.
• Heat. Keep pre-turbo EGT under 1,250 F and mount the pyrometer probe in the manifold, not the downpipe, which always reads lower.
• Exhaust brake and downpipe. Many aftermarket turbos use an HX40-style downpipe flange that eliminates the cast elbow. That changes downpipe fitment and means an inline exhaust brake instead of a turbo-mount one.

What we carry

This collection lists the ATS Diesel Performance Aurora Compound Turbo System, catalogued for 1994-2007 Cummins. That range covers the 12-valve, the 24-valve and the 2003-on common-rail 5.9L, so confirm the version for a 1998.5-2002 24-valve before you order. For single-turbo drop-ins and service parts, see our full turbos range or the Cummins hub.

Fitment and compliance

These are Dodge Ram 2500 and 3500 trucks only. Year and transmission decide which factory turbo you are replacing. CARB approval requires each product to be independently tested for emissions output, so confirm a CARB EO for performance parts on a California-registered truck. Verify by VIN.

Frequently asked questions

What is a compound turbo kit?

Two turbochargers working in series instead of one. It replaces the single factory Holset on trucks whose fueling has outgrown it. On this engine it is a build-level upgrade, not a first modification.

Do I need compounds to tow?

Not for a stock or mildly tuned truck. The factory turbo is adequate at stock power, and mild tow tunes give safe gains and better economy. Compounds make sense once injectors and tuning push past what a single turbo supports.

What else has to change with a compound kit?

Fuel supply, because the VP44 is cooled and lubricated by supply fuel. On automatics, the 47RE's roughly 450 lb-ft input rating comes into play. Add gauges for fuel pressure and EGT, and check exhaust brake fitment against the kit's downpipe flange.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.