Jeep Wrangler Diesel Conversion

Unrelenting, Powerful, Effective

There’s no such thing as too much torque…

Offroad Capability

With the diesel engines, power comes in at a low RPM giving you all the power you need right off of idle.

Fuel Economy

Not only will the diesel increase your fuel economy, but also provides the option of running alternative fuel sources like WVO.

Proven Reliability

With over 100 years of engine building and outstanding customer service, Cummins is the premiere name in diesel engine technology.

Cummins Diesel Options

Cummins 4BT

3.9L 4BT Diesel Conversion

The Cummins 4BT turbo diesel is the perfect option for the Jeep enthusiast wanting to improve their vehicle’s fuel efficiency and off-road capability. In addition to boasting increased fuel efficiency, the 4BT is also capable of running alternative fuel sources like Waste Vegetable Oil. All model years of the Wrangler platform, up to 2011, can utilize this conversion.


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4BT Specs

ConfigurationInline 4 Cylinder Turbo Diesel
Displacement3.9 L, 239 Cubic Inches
Bore4.02 inches
Stroke4.72 inches
Compression Ratio17.5:1
AspirationTurbo Charged, Non Intercooled
Engine Weight725-765 lbs
Oil Capacity10 Quarts
Horsepower105-170 hp@ 2300 RPM
Torque265-420 ftlbs@ 1600 RPM

Detailed Information

The 2007 to 2011 model years of the Jeep Wrangler, at present, are able to be upgraded. We remove the stock engine and transmission and then replace it with a Cummins 4BT and stronger transmission.


The 4BT is one of most proven reliable diesel engines in the world. If properly maintained, it is not uncommon for these engines to last beyond 350,000 miles.

Bruiser Conversions supplies a variety of engine power options for those seeking to upgrade their application.


4L70E HD – This automatic transmission is capable of withstanding 850 ft-lb of torque input.

NV4500 – This manual transmission is a proven warrior. It has been used predominately in diesel applications for years and is one of the most reliable manual transmissions available.




3.8L ISF Diesel Conversion

The ISF engine family is the newest addition to Cummins lineup. With exceptional performance, low weight, reduced operating costs, and the reliability and durability expected from Cummins, the ISF3.8 is ideal for light commercial vehicle applications such as trucks, vans, pickups, and utility vehicles. The ISF3.8 is the lightest and strongest engine in its displacement class and is the perfect choice for weight sensitive and space constrained installations above 3.5 tons GVW.

Check out our dyno results.

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ISF Specs

Horsepower170 hp @ 2600 RPM
Torque485 ftlbs @ 1300 RPM

Browse Our Gallery of Diesel ConversionsView Gallery

Diesel Conversion Pricing

 3.9L 4BT
Horsepower105 @ 2600rpm
Torque360 @ 1600rpm
Warranty1yr. / 12,000 miles
JK 2012+$29,500
JK 2007-2011$29,500
TJ 1997-2006$28,000
YJ 1987-1996$25,000
CJ5, CJ7, CJ8$22,500

4BT Options

Boost & EGT Gauge Pillar$1000
Transmission Conversion$3500



Is the diesel conversion street legal?

Our engine conversions are available as an “off-road only” application. We make no assertion that our conversions are street legal. This is not due to any mechanical limitation, but solely due to compliance with federal regulations regarding emissions and motor vehicle compliance. For further information please contact your local DMV.

What is the closest Bruiser Conversions location?

Bruiser Conversions’ primary facility is located in Clearwater, FL. There are Certified Installation Facility (CIF) locations in other states that provide LS Conversions, a list of these facilities can be found on our website.

What other modifications are needed?

The sky is the limit with Jeep upgrades and modifications, but most diesel conversions only require an additional 2″ of suspension height to compensate for the added weight of the engine.

What performance upgrades are available?

Bruiser Conversions has built relationships with many aftermarket and performance vendors, if you can dream it we can build it.  Please send an E-mail to our sales team at [email protected]