Members of the off-roading, Jeep-owning community have fallen in love with the Cummins 4BT engine. That’s because Jeeps with a 4BT engine have a greatly-improved off-roading capability. Here are some things you need to know.

Importance of the Cummins 4BT Engine to Jeep Owners

The 4BT engine is a 3.9-liter diesel engine that was created back in 1983 for bread trucks, step vans and other freight hauling vehicles. Despite the intended purpose of hauling, 4 x 4 vehicle owners saw the 4BT engine’s usefulness for off-roading purposes. They recognized that this engine:

• Had a much better torque ratio over other options

• Is the biggest diesel engine that they could fit into a Jeep

• Had great fuel economy

• Lasted an incredibly long time

• Could be upgraded in the future

Owners of various automotive models have had their factory engine replaced with a 4BT engine over the years. 4BT Jeep swaps have been the most common type of engine conversion, with the Wrangler’s engine being the most swapped engine.

The high-performance 4BT engine continues to prevent embarrassing incidents in 4 x 4’s due to underperformance. It also keeps passengers safer and increases off-roading fun. These engine conversions are the Jeep owner’s secret to his Jeep’s stellar performance, and the stellar performance is due to the 4BT engine’s high torque ratio.

Performance You Can Expect from a 4BT Engine

If off-roading is your priority, you need an improved power train. You want the engine in your four-wheeler to have a high torque ratio, such as you would get in a 4BT engine. Torque is the force produced by all four wheels at their points of contact on the ground. Torque is the engine’s strength. The engine type and the energy source affect torque.

The 4BT engine’s torque ratio is 265 lbs per foot of torque at 1,600 RPM. Performance upgrades can increase this to a whopping 750 lbs per foot of torque. A high torque ratio would give your Jeep a better ability to successfully make it up steep inclines.

If you settle for the street-level performance that Jeeps come from the factory with, you may roll your new Jeep and damage it. At the very least, your Jeep’s performance in some situations may embarrass you in front of your friends or family. Serious off-roading Jeep owners need an engine under the hood that has a high torque ratio. You’ll find that in a 4BT engine. However, the 4BT engine only has 105 horsepower at 2,300 RPM.

Fuel Economy You Can Expect from a 4BT Engine

You can expect a standard 4BT engine to give you between 18 and 20 mpg in the city and between 22 and 25 mpg on the highway. An upgraded engine gives between 28 and 30 mpg. A 4BT engine that has had a high level of modification done to it gives between 35 and 40 mpg.

Other Modifications You Can Expect to Need When Getting a 4BT Jeep Swap

Weighing about 800 pounds, a 4BT engine installed into a Wrangler would be one-third of the vehicle’s weight. That means that a Wrangler’s suspension and axles would need to be retrofitted. The same would be true for other smaller vehicles. Any engine-swapped 4 x 4 should have a balanced chassis.

Cost-Saving Tip

If you own a Jeep and you’re having engine problems, here’s a tip that may save you lots of money. A long block for a 4BT engine does not include the ancillary components. So, if your engine has a hard internal failure, but the water pump, inlet and exhaust manifold, turbo and the fuel system still work just fine, you need to just pay for a long block and for just a few hours of assembly time and labor. People think that getting an extended long block or a full reman unit is what they should do; however, doing that would cost you thousands of dollars more.

If you’re a Jeep-loving off-roader, you need your four-wheeler’s drive train to be well-suited for that purpose. You would get that from a 4BT engine. You need a 4BT Jeep conversion.