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S400 Single Turbos

S400 Single Turbo Kits for Cummins

For drivers who want maximum airflow and power, the Diesel Power Source S400 delivers. Built to handle high horsepower and heavy towing, the S400 is ideal for large single-turbo conversions or as the atmospheric charger in compound setups. Expect cooler EGTs, strong durability, and confident boost performance on your Cummins diesel.

DPS S400 turbos are engineered for high airflow with reliable street manners when sized correctly. On 5.9L and 6.7L Cummins platforms, the right S400 can widen the usable powerband, keep temperatures in check under load, and add headroom for future fueling upgrades. Choose from proven compressor sizes and turbine housings to match your goals for towing, daily driving, or competition.

How to choose the right S400 for your Cummins

  • Towing and daily use with future growth: Smaller S400 options with tighter turbine housings favor earlier spool and stable EGT on grades.
  • Street performance with headroom: Mid-size compressors balance response and top-end flow. Pair with a suitable manifold and clean charge-air path.
  • High fuel and race use: Larger compressor wheels and freer A/R housings support higher boost targets with tradeoffs in low-speed response.
  • Flange and housing: Match T4 or T6, wastegated or non-wastegated, and downpipe style to your manifold and exhaust.

What you can expect from an S400 upgrade

  • Lower EGT under load: High-flow turbine and scroll geometry reduce drive pressure during sustained towing and long pulls.
  • Stronger mid to top-end power: Added airflow supports clean combustion at higher fueling rates.
  • Durability and serviceability: Robust bearings, balanced rotating assemblies, and proven housings built for hard use.
  • Compatible with compounds: Works as a large single or as the atmospheric charger stacked over a stock or performance secondary.

Fitment

Compatible with 5.9L Cummins (1998.5–2007) and 6.7L Cummins (2007.5–2024) when equipped with the correct manifold, flange, and install hardware. Verify your truck’s year, intercooler piping, downpipe, and oil feed/return requirements on the product page before ordering.

Recommended supporting parts

  • Quality exhaust manifold matched to T4 or T6 flange
  • Charge-air boots and clamps rated for higher boost
  • Boost and EGT monitoring for towing and performance
  • Appropriate fueling and calibration if injectors or pump are upgraded

Planning a full system? See our Add-A-Turbo Kits, S300 Single Turbos, and 6.7 Cummins Exhaust Manifolds.

Signs your current turbo may need attention

  1. Noticeable power loss when accelerating or towing.
  2. Excess smoke that does not clear under load.
  3. Unusual sounds such as whining or scraping from the turbo area.
  4. Unexplained oil use without external leaks.
  5. Check engine light or boost-related fault codes.

Addressing issues early protects the engine and saves time. If you are unsure which S400 matches your setup and elevation, contact Diesel Power Source for a recommendation.

Frequently asked questions

Is an S400 practical for towing

Yes, with the correct size and turbine housing. Many towing builds prefer moderate compressor sizes and matched A/R for earlier spool and steady EGT on grades.

Do I need tuning with an S400

Most builds benefit from calibration to optimize fueling, vane control if applicable on compounds, and shift strategy. Upgraded injectors or pumps typically require tuning.

Single S400 or compound setup

A well-sized single S400 can meet many power goals. Compounds add low-speed response and thermal control at higher power. Choose based on use, altitude, and fueling.

What else should I upgrade

Use a quality manifold, ensure clean and leak-free charge-air plumbing, and add boost and EGT gauges. Consider transmission health if power goals increase significantly.

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