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Beta-Testing the R2.8 Diesel With Cummins

Playing Jeep with Cummins

Verne SimonsPhotographer, WriterStephen SandersPhotographer

If you haven’t heard the news that Cummins has a brand-new 2.8L diesel crate engine on the market, you need to get your eyes and ears checked. The name Cummins has long been ubiquitous in the light-, medium-, and heavy-duty diesel market and for good reason. Cummins engines deliver durability, power, and efficiency. In our world of off-roading 4x4s and tow rigs, engines like the 4BT, 6BT (AKA 12-valve 5.9L), 24-valve 5.9L, and 6.7L Cummins turbodiesels are second to none when it comes time to do work and make torque. And with this new Cummins crate engine available for $8,999, ready to run (literally, you can start it in the crate with a little fuel and a battery versus all the other à la carte crate engines out there), anyone with a pulse and a love for 4x4s has one on order, or wants to.

How cool is this engine? How easy is it to install? We have firsthand experience in both of these departments. First, the Cummins R2.8 Turbo Diesel we put in the UACJ-6D started right up once everything was in place and has run ever since without so much as a hiccup. As for drivability, now this old hunk of patina’d iron easily hauls oats down the highway at 75 mph all day long while getting 22-23 mpg. That’s amazing given the beadlocks, 38-inch mud tires, our heavy right foot, and the aerodynamic acumen of a rusted brick.

With all the miles we racked up on the UACJ-6D during this year’s Ultimate Adventure (as well as the return trip from Hurricane, Utah, to Peoria, Arizona) the Jeep and its R2.8 Turbo Diesel crate engine were itching for more action, so when the folks from Cummins invited us to join them for some high-altitude testing in Colorado we jumped at the chance. Unlike most of our trips, this one was almost all road-based (until the return trip, and for details on that check out the story “Colorado via UACJ-6D”). But the road miles were by design to give the Cummins engineers on the trip all sorts of over-the-road information, collected with onboard data loggers. In fact, the Cummins data logger in the UACJ-6D has been churning information straight back to the Indiana Cummins headquarters since it was first fired the day before Ultimate Adventure 2017 began.

With all the Cummins R2.8 Turbo Diesel–powered rigs such equipped, the plan was to drive the rigs hard, try to get them hot on long climbs, see how they run at altitudes 12,000 feet above sea level and higher—and then see how they run while compression breaking down the back side of the climbs. The engineers took notes on each rig, and we were all on the lookout for any hiccups or strange behavior, noting when and what happened and more. The trip was a blast, and we got a little bit of info on all of the rigs on the trip just for you. Check it out!

Tech Specs

1971 UACJ-6D
>Drivetrain
Engine: Cummins R2.8 Turbo Diesel
Transmission: SM420 with Advance Adapters Ranger Overdrive
Transfer Case: Offroad Design Magnum Box/Ford NP205
Axles: Dana Ultimate Dana 60, 4.88, Eaton E-locker (front and rear)
>Suspension
Springs & Such: Skyjacker Curt LeDuc Series coilover
Tires & Wheels: 38x13.50R17 Falken WildPeak M/T on 17x9 TrailReady HD beadlock
Other stuff: Lucky rock affixed to front bumper, new custom Ford Taurus fan and shroud
Built By: Petersen’s 4-Wheel & Off-Road

Tech Specs

2000 Jeep Wrangler TJ Sahara
>Drivetrain
Engine: Cummins R2.8 Turbo Diesel
Transmission: NV3500 5-speed
Transfer Case: NP231
Front Axle: Dana 30, 3.73
Rear Axle: Dana 44, 3.73
>Suspension
Springs & Such: Teraflex 2-inch
Tires & Wheels: Dodge Magnum steel wheels with 31x10.50R17 Goodyear Duratracs
Other stuff: ProComp Bumpers, Bestop frameless soft top
Built By: Axis Industries USA

Tech Specs

2010 Nissan Frontier SV 4x4
>Drivetrain
Engine: Cummins R2.8 Turbo Diesel
Transmission: Nissan 6-speed
Transfer Case: Nissan 2-speed
Axles: Nissan axles, 3.13 (front and rear)
>Suspension
Springs & Such: 2-inch Calmini
Tires & Wheels: Nissan steel with weld-on rock rings, 33x12.50R17 Goodyear Duratrac
Other stuff: ShrockWorks bumpers and rock sliders
Built By: Cummins

Tech Specs

1997 Jeep Wrangler TJ Submarine Tube-Sock Edition
>Drivetrain
Engine: Cummins R2.8 Turbo Diesel
Transmission: NV3500
Transfer Case: Advance Adapters Atlas II 4.3:1
Front Axle: Currie Dana 44, 5.38, ARB Air Locker
Rear Axle: Currie RockJock 60, 5.38, ARB Air Locker
>Suspension
Springs & Such: BDS coils, Fox shocks (front and rear)
Tires & Wheels: 38x13.50R17 Falken WildPeak M/T, American Racing Chamber Pro beadlock
Other stuff: Bestop soft top, Custom doggy dishes and sleepy nests
Built By: Advance Adapters, Dave Chappelle, and the Fredling