Patented Variable Geometry Technology for S300 & S400 Platforms | 5.9L, 6.7L, Ford 6.0
The Diesel Power Source® Turbonator® VGT is a patented variable geometry turbocharger upgrade available on S300 and S400 platform turbos for 1988–2018 Cummins applications. The VGT turbine housing replaces a fixed A/R housing with variable geometry vanes that continuously adjust exhaust flow — delivering the spool of a tight A/R at low RPM and the top-end airflow of a large A/R at high RPM. No fixed A/R turbo can do both.
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Every Turbonator® VGT is available as a complete turbocharger (compressor + turbine + CHRA) or as a housing-only upgrade for customers who want to add variable geometry to an existing S300 or S400 build. The electronic version adds exhaust braking capability through a dash-mounted controller. Both T3 and T4 flanges are available across the lineup.
Compared to a fixed A/R turbo of the same compressor wheel size
Electronic version adds engine braking — no compressor needed
Infinitely variable between tight spool and maximum top-end flow
T3 and T4 flanges — fits any DPS compound or single turbo build
The Turbonator® VGT is available as a complete turbocharger or housing-only upgrade. Select your application below.
A standard fixed A/R turbo is a compromise. A tight A/R (e.g., 0.65) spools fast at low RPM but restricts flow and creates high drive pressure at the top end. A loose A/R (e.g., 1.0) breathes well at high RPM but spools slowly at low RPM. Every fixed A/R turbo picks a point between those two extremes and stays there regardless of what the engine needs.
The Turbonator® VGT eliminates that compromise. The variable geometry vanes start at approximately 0.45 A/R — tighter than almost any fixed A/R turbo on the market — which maximizes exhaust gas velocity at low RPM and spools the turbo faster. As engine speed and exhaust flow increase, the vanes open automatically, reaching 1.1 A/R at peak flow for maximum top-end airflow. The result is faster spool than a tight-A/R turbo combined with better top-end flow than a loose-A/R turbo — in a single housing.
On the S300 platform, the Turbonator® VGT typically improves spool-up by 200–300 RPM compared to a fixed A/R turbo of the same compressor wheel size. This is a driver-noticeable difference — particularly under towing load and from a stop.
| Comparison | Fixed A/R Turbo | Turbonator® VGT |
|---|---|---|
| A/R at low RPM | Fixed (e.g., 0.70) | ~0.45 (maximum spool) |
| A/R at high RPM | Fixed (e.g., 0.70) | ~1.1 (maximum flow) |
| Spool vs same wheel size | Baseline | 200–300 RPM faster |
| Exhaust brake capable | No | Yes (electronic version) |
| Adjustable vane position | No | Yes (dash-mounted dial, 0–11) |
The Turbonator® VGT is available with two actuator options. The right choice depends on whether exhaust brake capability is needed.
For customers who tow regularly or want exhaust braking functionality, the electronic actuator is the recommended choice.
The Turbonator® VGT is also available as an upgrade option on any DPS compound turbo kit. When added to the S300 high-pressure turbo in a compound system, the VGT provides two additional benefits beyond the standard compound kit:
The Turbonator® VGT compound option is available on 5.9L and 6.7L Cummins 1988–2018. See the individual compound turbo kit pages for configuration options.
Customers who already have a DPS S300 or S400 turbo can add Turbonator® VGT capability through the housing-only upgrade. The VGT housing replaces the existing fixed A/R turbine housing on any compatible S300 or S400 turbo. Available in T3 and T4 flanges.
This is a cost-effective way to add variable geometry spool and exhaust brake capability to an existing turbo without replacing the entire unit.
A variable geometry turbocharger (VGT) uses moveable vanes in the turbine housing to control exhaust flow and effective A/R ratio. At low RPM the vanes close to accelerate exhaust gas and spool the turbo faster. At high RPM the vanes open to allow maximum flow. The Turbonator® VGT operates from approximately 0.45 A/R (vanes closed) to 1.1 A/R (vanes fully open) — a range no fixed A/R turbo can match.
Yes. The Turbonator® VGT is fully compatible with EGR, DPF, and DEF systems. DPS does not sell emissions delete components. The Turbonator® VGT is designed to improve performance while keeping all factory emissions equipment intact.
Yes — and the electronic version actually adds exhaust brake capability to trucks and builds that don't have it. The electronic actuator monitors the truck's existing exhaust brake signal and closes the VGT vanes to provide engine braking. On deleted trucks or compound builds without factory exhaust brake, the electronic Turbonator® VGT adds the capability from scratch.
The dash-mounted dial (0–11 scale) sets the baseline vane position — where the controller starts the vanes at low throttle before the control logic begins modulating them. The recommended starting range is 4–7 for most applications. Higher numbers do not automatically mean more power — finding the right position for your specific truck is a tuning step. Start at 5 or 6 and adjust one click at a time based on feel.
The factory HE300VG and HE400VG on the 6.7L Cummins are also variable geometry turbos — so the Turbonator® VGT is not being compared to a fixed A/R turbo in that case. The Turbonator® VGT is an S300 or S400 platform upgrade, built on a different (and larger) compressor platform than the factory Holset. The right comparison is Turbonator® VGT vs. a fixed A/R S300 or S400 of the same compressor wheel — and on that comparison, the VGT wins 200–300 RPM of spool.
Yes. If you already have a DPS compound kit with a fixed A/R S300 high-pressure turbo, you can upgrade to the Turbonator® VGT housing through the housing-only option. This adds variable geometry spool and exhaust brake capability without replacing the entire turbo. Contact DPS to confirm compatibility with your specific compound kit configuration.
The Turbonator® VGT is available in T3 and T4 flanges on both S300 and S400 platforms. The 6.7L Cummins ball bearing T4i version uses a T4i flange for direct bolt-on to the factory 6.7L manifold location. Specify your flange requirement at time of order.
Yes. The Turbonator® VGT variable geometry housing design is a patented Diesel Power Source® innovation. It is not available from any other manufacturer in the same configuration.
Related products: Compound Turbo Kits | S300 Single Turbos | S400 Single Turbos | Exhaust Manifolds | 3rd Gen Swap Kits | Stuck Turbo Syndrome Guide
Turbonator® VGTs are enhanced-performance VGT turbos—not just stock replacements.
Key improvements over stock VGT:
Compare to basic stock replacement:
Yet maintains all OEM features: Emissions compatibility, tow/haul mode, exhaust brake, factory-like drivability.
These three codes all point to the VGT (variable geometry turbocharger) system on the 6.7L Cummins. P003A means the actuator's position has exceeded its learned limit — the ECM commanded a vane position the actuator couldn't reach or hold. P2262 means boost pressure was not mechanically detected when expected, indicating an actuator problem, stuck vanes, boost leak, or physical turbo damage. P226C means the VGT position relearn was never completed after a turbo or actuator replacement, so the ECM can't accurately control vane position. Each code has a distinct cause and requires a different starting point for diagnosis.
Turbonator® VGTs support 400-500+ HP with proper tuning and supporting modifications.
Power ranges by model:
Supporting mods for these power levels:
Real-world performance gains:
Yes—Turbonator VGTs are designed to maintain full emissions compatibility.
Works with all factory emissions systems:
Street-legal in emissions-regulated states:
⚠️ Important: While the turbo itself is emissions-compatible, your tuning must also be emissions-compliant to remain street-legal. Work with tuners who understand emissions-on programming.
Yes—100% of factory functionality is retained.
Features that continue working perfectly:
Why this matters for towing:
This is a major advantage over fixed-geometry turbos (S300, S400 singles), which eliminate VGT-based exhaust brake and engine braking.
Turbonator VGTs and HE-series VGTs are similar concepts with slightly different approaches:
Similarities:
Key differences:
Which to choose?
Contact our tech team to discuss which VGT option best fits your specific truck, power goals, and budget.
Installation is straightforward—similar to replacing any stock VGT turbo.
Installation time:
Why installation is easier than fixed-geometry turbos:
Installation steps (overview):
Tools needed: Socket set, wrenches, jack and stands, penetrating oil, torque wrench. No special tools required.
Our kits include detailed photo instructions and we offer phone/email support during installation.
A VGT (Variable Geometry Turbocharger) uses a set of movable internal vanes to change the turbo's flow characteristics based on engine speed and load. At low RPM the vanes close to increase exhaust velocity and spool the turbo quickly. At high RPM they open to allow maximum airflow. On the 6.7L Cummins, an electronic actuator mounted to the turbo controls vane position based on commands from the ECM. This design also enables exhaust brake function — the ECM closes the vanes to create backpressure that slows the truck without using the friction brakes.
The two most common failures are carbon buildup on the internal vane assembly and electronic actuator failure. Carbon accumulates from exhaust soot over time and causes the vanes to stick or seize, resulting in low boost, black smoke, and reduced throttle response. The actuator is mounted in a high-heat environment and can fail mechanically or electronically — common fault codes include P2262 and P226C. In many cases the vanes are fine and only the actuator needs replacement. Maintaining clean oil and monitoring EGTs are the most effective ways to extend VGT life.
Yes. Any time a VGT turbo or actuator is replaced on a 6.7L Cummins, the actuator must be calibrated using a scan tool that supports bi-directional VGT control. This procedure teaches the ECM the actuator's full range of travel. Skipping it will result in continued fault codes even with a new, fully functional actuator or turbo installed. The Turbonator VGT is a direct plug-in replacement that uses the factory actuator connector, so the relearn procedure is the same as a stock turbo replacement.
A VGT controller manages vane position either independently of or alongside the factory ECM's commands. On stock or mildly tuned trucks, the factory control strategy is sufficient. On heavily tuned builds with elevated boost and fueling targets, the ECM may not open the vanes aggressively enough at high loads, causing excessive backpressure and elevated EGTs. An aftermarket VGT controller lets the vane position be tuned alongside fueling and boost strategy. For most Turbonator® VGT applications paired with a moderate tune, the factory controller is adequate — your tuner can advise if your specific power level warrants an aftermarket unit.
