Wehrli 03-07 Dodge 5.9L Cummins S400 Twin Turbo Kit (No Turbo) - Flat Black

If you're looking to significantly boost the performance of your 2003-2007 Dodge 5.9L Cummins, this twin turbo kit from Wehrli Custom Fabrication is a solid option. This kit is designed to work with an S400-style charger and your stock Holset turbo, or with upgraded drop-in turbos, to help you reach up to 1000 rear-wheel horsepower, depending on your fuel system and other modifications. It's a popular choice for daily drivers and tow rigs that need more power, better fuel economy, and improved Exhaust Gas Temperature (EGT) control, all while maintaining a turbo spool that feels similar to stock.

Wehrli has put together a comprehensive package here. The hot side components and the downpipe are treated with a high-temperature black ceramic coating to help manage heat. You'll get stainless steel lines for oil feed and drain, complete with the necessary fittings. The kit also includes silicone boots and stainless steel T-bolt clamps for secure connections, a 3-inch cold charge pipe to connect the turbos, and a 3-inch hot side crossover pipe. Installation hardware, including V-band clamps, O-ring seals, heat wrap, and clamps, is all included to make the job smoother. This kit retains the factory passenger-side battery location, simplifying the install. The custom powder coat finish adds a durable and clean look.

This kit comes without the turbos themselves, allowing you to select the S400-style charger that best fits your build goals. For up to 750 RWHP with good spool, an S475 is a great match, especially with stock fuel. If you're aiming for 800+ RWHP, an S480 is recommended, offering more top-end power but with a slightly slower spool. For the highest power levels, 900+ RWHP, an S480 paired with an upgraded 63, 64, or 67mm drop-in turbo is the way to go, though the larger options are not recommended for tow rigs due to their spool characteristics. A 5-inch intake is also part of the package.