Can a bigger turbo actually make more power on stock injectors? That’s exactly what we set out to test with our VP44 24-valve Cummins truck, Willard. In this video, we swap the factory HX35 for our Aggressor 60-64 and put it through a same-day dyno comparison with zero changes to fueling or tuning. No injector upgrades, no custom tuning, just a straight turbo swap. From there, we hit the road with a loaded trailer to test drivability and EGT control under real-world towing conditions.
We break down the dyno results, boost-to-drive pressure ratios, EGT differences, and overall performance between the HX35 and the 6064. The Aggressor 6064 didn’t just make more power, it picked up torque across the curve, ran cooler under load, and held boost more efficiently. Peak power increased by around 11 horsepower, but the gains were felt throughout the entire RPM range. Even more impressive was the EGT drop, with temperatures coming down over 100 degrees in the middle of the run.
That’s the kind of performance difference that matters when you’re towing hard or daily driving in hot weather.
We also take you through some install notes, including why our stainless cast turbo elbow is a solid upgrade, how to bolt the new charger to a stock manifold, and what hardware you’ll need to make it fit. If you’re planning this swap on your own VP44 truck, you’ll get a solid look at what to expect and how to get it done right.
After road testing the setup, we dive into the topic of boost-limited tuning and why our Quad setup may be holding this turbo back from showing its full potential. The truck spools a touch slower than stock, but response is still crisp and power delivery is smooth, even with a heavy trailer behind it. We think some custom tuning could really unlock this setup, but we want to hear from you. Should we tune it next or jump straight into injector upgrades?
If you’re running a VP44 truck in the 300 to 400 horsepower range and looking for better efficiency, lower EGTs, and more towing power without sacrificing drivability, this video will give you a real-world look at what a properly sized turbo can do without touching your injectors.
Let us know what you want to see next in the comments. Make sure to like, subscribe, and follow along as we keep pushing the limits of this build.
Power Driven Diesel is a specialty performance shop engaged in the engineering and development of high-performance turbo diesel technologies.
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