by Scott EilersUpdated on November 07, 2017
Jeep is a subdivision of the Daimler-Chrysler company that produces primarily off-road and sports vehicles. The Jeep 4.0L engine was a six-cylinder engine used in many Jeep vehicles from 1984 to 2003, including the Cherokee and the Wrangler. The engine underwent a number of changes during its nearly 20-year lifespan, including many internal enhancements that increased the vehicle’s available power. All Jeep 4.0L engines have a variety of high-performance parts available that increase horsepower when installed.
Replace the Jeep cold air intake with a high performance aftermarket cold air intake. High-performance aftermarket cold air intakes increase horsepower by improving cold air flow to the engine. They are relatively simple to install without professional assistance and are one of the least expensive performance upgrades available for Jeep vehicles. They may slightly increase engine noise, but are generally not inconvenient when installed correctly.
Replace the Jeep exhaust system with a high performance aftermarket exhaust system. Aftermarket high-performance exhaust systems increase horsepower by improving the flow of hot air out of the engine. They generally require professional installation as access to the underside of the vehicle is needed. They substantially increase engine noise, although many Jeep owners find the louder and more aggressive engine note desirable. However, they also increase emissions and can cause your vehicle to lose street legal status in some states. Check your state regulations before doing this update.
Install a forced induction kit on your Jeep 4.0L engine. Forced induction kits increase horsepower by forcing a large amount of air into the air / fuel mixture within the engine itself. They are relatively difficult to install and can be extremely expensive. They also reduce fuel economy, dramatically in some situations, and increase overall wear and tear on your Jeep. However, they can double the horsepower of your Jeep depending on the size of the turbocharger you install.
Install a nitrous oxide injection kit. Unlike other performance modifications, nitrous oxide injection kits do not permanently change the way your car works. They allow the driver to inject a dose of nitrous oxide into the fuel system with the push of a button or the pull of a level, providing a large but temporary boost to available power. These kits are typically designed for straight-line racing and, like forced induction kits, will increase the overall wear and tear on your Jeep when activated.