1993 Jeep Wrangler YJ - Cummins Jeep Swap

This is the heart of the Jeep: a '96 3.9L Cummins four-cylinder turbodiesel. The fit was tight on the passenger side, but once the installation was complete, it almost looks like Jeep put it in from the factory.

The engine is mated to a GM TH400 three-speed automatic that was originally behind the Cummins engine. The transmission was fitted with an Advance Adapters output shaft that allowed it to mate up with the Jeep's original NP231 transfer case.

The GM power-steering pump was plumbed to run the Jeep's original power steering and retrofitted hydroboost brakes from a 1-ton Chevy truck.

The latest addition to the Cummins-powered Jeep is the Snow Performance Boost Cooler that was added until a conventional air-to-air intercooler can be fabricated. This water/methanol injection system works like a liquidation air intercooler and helps to lower the exhaust gas temperature by almost 200 degrees Fahrenheit.

The tank for water/methanol injection is installed on the driver-side of the Jeep, just ahead of the engine on a custom mounting bracket.

The "Eleanor" hood was required to make room for the turbine tube from the turbo to the intake. The scoop was originally added to make room for the supercharger on the 4.0L. The hood scoop won't be necessary once the intercooler is plumbed in.

The air snorkel was carried over from when the Jeep had the 4.0L engine. Clifton modified the top to accept a K&N filter under the top hat, just like the 18-wheelers have.

The interior is set up with a CB radio, gauges to monitor all the engine functions, power windows, and floor shifter for the new automatic.

The wrong fuel in this Jeep could get cost between $400 and $1,000 to correct, so Clifton made sure there were notes near the fuel gauge and cap to help those who may not know.

The wheels are Hutchinson Rock Monsters and are the only DOT-approved bead locks for street use. They're very similar to the wheels that Hutchinson makes for the Hummer H1. The Interco Truxus tires work well with the Jeep and take it places some tires fear to tread.

The new low-end torque of the Cummins quickly made mincemeat out of the factory rear axle. A 31-spline Ford Explorer 8.8-inch rear axle with disc brakes was swapped in and fitted with a Detroit Locker.