Dark Iron Diesel Tests Dynomite Diesel Injectors On A 6.7L Cummins And The Results Are Impressive

Builders pushing fifth-generation Cummins engines know it takes more than slapping on a compound turbo kit to make big power. They must also feed those cylinders massive fuel volume to unlock serious performance. Dark Iron Diesel secured a baseline dyno run of 449 peak horsepower and 780 lb-ft of torque before tearing into the engine.

Horsepower Gain From Bigger Injectors

The fuel system upgrade required installing brand-new components from Dynomite Diesel Products. Extreme patience is necessary when removing the old hardware to avoid damaging internal lines. Kyle noted: “So, before we pull the injector, we have to break this jam nut loose. We’re going to pull it right off the fuel tube.” Next, he dropped the fresh 45 percent over units into the block alongside new OEM Bosch tubes. Securing everything perfectly required a strict torque sequence.

Tuning The Upgraded Fuel System

Initially, firing up the truck produced a clean idle without any custom software. Kyle spun the rollers on the factory calibration, yielding a modest power bump. Afterward, he flashed a custom file from Peak Side Performance to fully utilize the mechanical modifications. That first heavy pull spooled the turbos incredibly fast but bogged down near 3,000 rpm. A quick data log revealed the engine was hitting a boost limiter and dropping massive rail pressure.

Breaking The 600-Horsepower Barrier

Adjusting the tuning parameters completely transformed the heavy pickup. They loaded a revised flash file, instantly shooting the output up to 586 horsepower. Pushing the factory injection pump to the edge, the team received one final adjustment to find the absolute mechanical limit. That final aggressive run delivered highly impressive numbers. Celebrating the massive jump, Kyle stated: “601 horsepower and just over 1,000 foot lbs of torque. So, we have a 600 horsepower truck wheels with wides on.”

Future Plans For The Cummins Build

A quick highway test drive proved the compound turbos pair perfectly with heavy fueling. Launching the truck in four-wheel drive kept engine speeds high while maintaining incredibly low exhaust gas temperatures. Meanwhile, maxing out the stock CP3 pump means the team must install a high-flow stroker unit next. Unlocking even more track potential relies entirely on supporting the massive horsepower gain from bigger injectors with stronger internal components.