Boost Your Power: Best Turbo Upgrades for Diesel Trucks

Recognizing the Signs: When to Upgrade Your OEM Turbo

Before you can specify a solution, you have to accurately diagnose the problem. An OEM turbocharger is a compromise, designed for mass production and specific emissions targets, not maximum performance or longevity under heavy use. As mileage racks up or power-adding modifications are introduced, its limitations become clear. Symptoms can range from a noticeable loss in performance to a catastrophic failure that sends debris through the engine.

Key indicators include consistently high EGTs when towing, a visible haze of black or blue smoke from the exhaust, or a sluggish throttle response. You might also hear abnormal noises, like a high-pitched dentist drill whine (indicating bearing failure) or a siren sound that changes with engine RPM. These are all signals that your turbo is either failing or simply can't keep up with the engine's demand for air. The following chart is our real fix checklist for turbo-related issues.

VGT vs. Fixed Geometry: The Core Tradeoff

Modern diesel trucks primarily use Variable Geometry Turbos (VGTs), also known as Variable Nozzle Turbines (VNTs). These units have adjustable vanes inside the turbine housing that can change the exhaust gas velocity acting on the turbine wheel. At low RPM, the vanes close to increase velocity, spooling the turbo quickly for excellent throttle response. At high RPM, they open up to maximize flow and prevent excessive backpressure. This technology gives you the best of both worlds: the quick response of a small turbo and the top-end power of a large one.

Fixed geometry turbos are the classic, simpler design. They have a fixed, non-adjustable turbine housing, defined by an A/R ratio. They are generally more robust, less complex, and can support extremely high horsepower levels. The tradeoff is in responsiveness. A large fixed geometry turbo that makes huge power at 4,000 RPM may feel laggy in daily driving situations. Smaller fixed geometry turbos can be responsive but will choke the engine and create high EGTs at higher RPMs.

For most trucks that are daily driven or used for heavy towing, a modern, well-designed VGT is the superior choice. It provides a wide, usable powerband that makes the truck more drivable and efficient. However, for dedicated competition or very high-horsepower builds, the durability and peak flow of a large fixed-geometry turbo might be the better path.

Key Metrics for Choosing a Performance Turbo

When you move beyond OEM replacements, you'll encounter a new set of specs. Understanding them is critical to matching a turbo to your engine and goals. Don't get fixated on 'boost' numbers alone; airflow (measured in lbs/min) is what makes power. Boost is just a measure of restriction.

The most important components are the compressor and turbine wheels. The compressor wheel (the intake side) is often described by its inducer and exducer diameters. A larger inducer allows more air to enter, while the exducer's size and blade design influence the wheel's efficiency range. Billet compressor wheels, often with more aggressive blade profiles, are stronger and can be machined with more complex aerodynamics than cast wheels, allowing them to move more air efficiently.

On the exhaust side, the turbine wheel and its housing work to drive the compressor. The turbine housing's A/R (Area/Radius) ratio dictates how it responds. A smaller A/R ratio (e.g., 0.90) will spool faster but may be restrictive at high RPM, increasing drive pressure. A larger A/R (e.g., 1.10) will flow more on the top end but will be laggier. For a VGT, the vane assembly effectively provides a dynamic A/R ratio.

• <span style="background-color:#FFFF00">Compressor Inducer/Exducer:</span> The primary measure of a compressor's size and flow potential.
• <span style="background-color:#FFFF00">Turbine A/R Ratio (Fixed Geometry):</span> Determines the tradeoff between spool-up and top-end flow.
• <span style="background-color:#FFFF00">Wheel Material & Design:</span> Billet wheels offer higher strength and more advanced aerodynamic designs over traditional cast wheels.
• <span style="background-color:#FFFF00">Wastegate Type:</span> Internal or external wastegates control boost pressure to prevent overspeeding the turbo. VGTs use the vanes for boost control.
• <span style="background-color:#FFFF00">Bearing System:</span> Journal bearings are common and robust, while ball-bearing systems offer slightly faster transient response but come at a higher cost and sensitivity to oil contamination.

What Good Looks Like: Drop-in vs. Custom Kits

Turbo upgrades fall into two main categories: drop-in replacements and full custom kits. A drop-in, or 'stock appearing', upgrade is designed to bolt into the factory location using all the stock connections for oil, coolant, intake, and exhaust. This is what good looks like for the vast majority of truck owners.

These turbos, like our Screamer series, retain the stock housing but feature significantly upgraded internals. This includes a larger and more efficient billet compressor wheel and often a new turbine wheel profile. The result is a turbo that supports 50-150+ more horsepower, lowers EGTs, and improves response, all without requiring custom fabrication. Installation is straightforward, making it a cost-effective path to major performance gains.

Custom kits, often called 'second-gen swaps' on Cummins platforms, involve relocating the turbo using a different exhaust manifold and fabricating custom charge pipes, downpipes, and oil lines. These kits allow the use of large-frame, fixed-geometry turbos (like S300 or S400 frame units) that can support extreme horsepower (800hp+). While they offer the highest performance ceiling, they come with substantial cost, complexity, and fabrication requirements. They often sacrifice the low-end response that is critical for a street-driven or towing truck.

Platform-Specific Turbo Upgrade Paths

While the principles are universal, the specific turbo choices and weak points vary by manufacturer. Each engine family has a well-trodden upgrade path.

Ram Cummins (5.9L & 6.7L)

The 6.7L Cummins has been equipped with a Holset VGT since 2007.5. These are stout units, but the actuators are a common failure point, and they can be restrictive with aggressive tuning. A Screamer HE351 (2007.5-2012) or HE300VG (2013-2018) provides a significant airflow increase with a more durable design. The drop-in nature is a huge plus, directly replacing the failure-prone stock unit while supporting more power and providing better EGT control for towing.

Ford Power Stroke (6.7L)

As mentioned, the 2011-2014 6.7L Power Stroke's GT32 SST is a liability. A popular and essential reliability upgrade is a retrofit kit to install the more robust single-sequential GT37-style turbo from the 2015+ trucks. Our Screamer Stage 2 GT37 Retrofit Kit is a complete bolt-on solution. For 2020+ trucks, the OEM VGT is actually a very capable unit, but can still be improved with a drop-in like our Screamer for the 2020-2022 6.7L for those pushing the power limits.

GM Duramax (6.6L)

Duramax engines have used VGTs since the LLY in 2004.5. Early LLYs were known for overheating, partly due to a restrictive turbo mouthpiece. Later models like the LBZ and LMM had more robust turbo designs. However, all can benefit from an upgrade when pushing past stock power levels. Upgrades for these platforms focus on larger compressor wheels and more durable VGT mechanisms to handle higher boost and fuel levels. Whether you have an early LB7 or a later LML, a properly sized performance turbo is key to making reliable power.

The Fix-First Roadmap for Installation

Bolting on a new turbo is only half the job. A successful upgrade depends on ensuring the supporting systems are in perfect working order. A new turbo can easily be damaged by a pre-existing problem. Our fix-first roadmap ensures your investment is protected and performs as it should from day one.

This isn't just about swapping parts; it's about system integrity. A clogged oil drain can starve a new bearing just as easily as a dirty oil feed. An old, cracked exhaust manifold can warp the new turbo's flange, causing a permanent leak. Taking the time to go through this checklist will save you immense time and money down the road.

Expected Costs for a Diesel Turbo Upgrade

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  Screamer HE300VG Turbo Dodge 6.7L Cummins 2013-2018A drop-in, stock-appearing replacement that flows more air for better performance and EGT control. Features a larger Ballistic Billet compressor wheel and a Low MOI QST turbine to improve response.
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  Screamer Stage 2 GT37 Retrofit Turbo Kit - Ford 6.7L Power Stroke 2011-2014Replaces the problematic factory GT32 with the more reliable and higher-flowing GT37 design from the 2015+ trucks. A complete kit for a bolt-on reliability and performance upgrade.
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  SCREAMER TURBOCHARGERS FORD F-250/F-350/F450 6.7L POWERSTROKE 2020-2022A drop-in upgrade for late model Power Strokes built from a new Genuine Ford turbo. The rotating assembly is upgraded with a larger compressor for higher flow, supporting more power at a safer boost level.
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