How to Add More Horsepower to a 5.7 HEMI

by Zyon SilketUpdated November 07, 2017
itstillruns article image
Yellow grill image by Viktor Gmyria from

Items you will need

  • Aluminum flywheel

  • Aluminum drive shaft

  • ECU flash tuner

  • Cold air intake

  • Large bore throttle body

The 5.7 HEMI engine is available in the Dodge, Chrysler and Jeep vehicles, making it one of the most popular engines available today. Although the HEMI engine has several significant differences in its combustion chamber from other engines, it is still a modern, computerized engine that pulls air and fuel into the combustion chamber and then uses a spark to ignite the mixture. Because of this, there are multiple ways to easily increase the horsepower intake of the 5.7 HEMI engine.

Reduce engine weight by replacing the iron flywheel with a lightweight aluminum flywheel. The weight reduction allows the engine to rev faster; thus, power can be transferred to the rear tires faster. This improves torque and overall horsepower of the HEMI engine.

Change the iron drive shaft with an aluminum drive shaft. In vehicles with less than 900 horsepower, an aluminum drive shaft reduces the amount of horsepower it takes to spin the drive shaft. This increases the amount of horsepower delivered to the rear wheels.

Flash the ECU (electronic control unit) to take advantage of horsepower that is restricted by the manufacturer. The ECU acts as the brain of the HEMI engine, telling the engine how much air, fuel and spark to deliver to the combustion chamber. By flashing the ECU, the engine will run with better efficiency and with more horsepower.

Replace the stock air filter and air intake box with a cold air intake. A cold air intake eliminates the box and collects air from the inner fender well via a large air filter. The air in the fender well is cooler than the air in the stock air box; thus, the air taken into the engine can be cooler. The cooler air and the larger amount of air going into the engine increases the efficiency of combustion. Installing a large-bore throttle body ensures the higher airflow is not restricted before it gets into the engine. This will aid to the increase of horsepower.

More Articles

article divider