Hot Rod HMMWV: Vice Unlimited’s Cummins-Powered Masterpiece [Video]

Building unique vehicles is nothing new to Tim Odell. In fact, the Vice Unlimited owner is the man responsible for some of the most incredible builds we’ve seen in recent history. When he’s not building things like the Legend Jeeps or the Cummins-powered Colorado Kymera for clients, he’s wrenching on one of his personal projects. His latest build started off with a platform that’s known the world over: the military HMMWV (High Mobility Multi-Purpose Wheeled Vehicle). Now being phased out of active duty, the HMMWV (or Humvees as they are often called) are pouring onto government liquidation sites.

When he picked up his 1992 four-passenger open-top version, it was a far cry from what you see here today. The main draw of the HMMWV for Odell was his want to build a top and door kit for them. Of course, once he started working with the nearly 30-year-old military truck, he realized the body wasn’t the only area that would need some help. Aside from the zero-comfort military-spec seats, the stock 6.2L diesel was painfully slow. Luckily, a quick search at his local wrecking yard yielded junkyard gold: an intact 5.9L 24-valve Cummins engine sitting in a 2003 Dodge Ram.

While you can learn more about the how his HMMWV came together from the man himself in the video above, we’re diving into the details in our feature breakdown below.

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Cummins Swap

The original HMMWV’s came with an anemic naturally aspirated 6.2L diesel engine. At Vice Unlimited, Odell is used to removing these relic V8s in favor of more powerful Duramax and Cummins engines. For his personal build, he went with the modern 5.9L Cummins. To get the power numbers up a bit, he had a custom tune applied to the Smarty engine tuner. This bumps the horsepower up to 400 and the torque figures north of 650.

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While the 24-valve engine retains the stock turbo, it gets air upgrades thanks to a four-inch turbo-back exhaust system. The intake on the HMMWV was also modified to allow for greater flow and to use a more conventional K&N air filter. Helping to feed the common-rail engine is an Air Dog fuel pump and filter setup.

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To keep the forced air temps down, Odell built custom charge pipes and modified the OE intercooler from the ’03 Ram truck. Coupled with the custom slant-mount setup is the stock radiator and Derale transmission cooler.

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In order to allow the forward driveshaft to connect with the front differential, the oil pan on the Cummins engine needed to be modified. Since the new engine and transmission combo was longer than the original, a new front driveline was also added.

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Controlling the ignition, lights and majority of the gauges is a dash-mounted iPad. While the HMMWV still uses dual batteries, it’s been converted from 24 to 12-volt. Mounted behind the inline-six engine is a 4L80E transmission. It’s been fit with a custom torque converter along with billet internals. It now receives its marching orders from a US Shift stand-alone control module.

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Unmatched Ground Clearance 

One of the features that make the HMMWV so unique and effective for the military is the 16 inches of ground clearance. This is achieved by using center-mounted AMC 20 differentials front and rear. These have been flipped from their original low-pinion configuration to a high-pinion configuration. The reason for the flip is so the half-shafts powering from the diff will turn the two-gear portal hubs in the correct direction. The combination of the 2.73:1 differential ratio combined with the 1.92:1 at the hubs equates to a 5.24:1 final drive ratio. If you look closely next to the differential housing, you can see the disc brake setup that’s tucked neatly out of harm’s way.

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Aside from changing the oil and upgrading the idler arm, the suspension and remainder of the drivetrain remains as it came from the factory. All HMMWVs are built with a massive IFS/IRS coil and shock configuration.

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Some of the modern touches you’ll find throughout the build include the assortment of LED lighting. You may also notice that this HMMWV looks a tad taller than most. That’s due to the custom three-inch body lift that was necessary in order to fit the Cummins engine under the hood. With the increased separation from the body to the frame, Odell built a custom gap guard for the front and fabricated the chassis air lift mounts you see poking through the hood.

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Locked & Loaded 

Thanks to the added lift, Odell was able to move up to a 40x13.50R17 Nitto Trail Grappler. The Trail Grappler has been a go-to tire for Odell on a few of his builds as it's one of the only tires of its size to offer uncompromised off-road performance with excellent street manners. These massive mud-terrain radials were paired with a custom set of 17-inch KMC Enduro beadlock wheels. These cast-aluminum wheels are built with similar backspacing as the OE military wheel, but are significantly lighter.

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

Cooling the interior is a Magnum kit from Vintage Air. It’s mounted in the back, with custom ducting piped throughout. Sitting just left of the Joes Racing Products steering wheel is an Equus gauge set. One reads the engine’s oil pressure, while the other monitors the fuel amount in the Vice Unlimited fuel cell.

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

Stow 'n Go

If you’ve never peaked inside of a HMMWV, you might be surprised at how far you sit apart from the other passengers. This is due to the drivetrain being tucked high within the body. To add modern comforts to the extremely spartan interior, Odell laid a ½-inch layer of sound deadening material throughout the cabin, then covered it with carpet. The seats mount via the Vice Unlimited front pedestal and rear plate set and were sourced from a brand-new Dodge Caravan. Not only do the seats fit perfectly, but they have the Stow ‘n Go feature built in!

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

Odell’s background in bodywork gave him the upper hand when it came to making a hard door and top for the HMMWV. The doors are actually modeled after what’s commonly known in the HMMWV enthusiast world as the X door. It ties that styling with the armored window-look, creating the unique setup you see here. Each door is comprised of 3/16-inch aluminum to keep weight down and are built to be weather tight.

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

Like the doors, the Vice Unlimited hard top kit is comprised of 3/16-inch aluminum. These have a full back glass along with a heavy-duty drip rail.

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

Out back, you’ll find an air-lift series rear bumper, which has been mated with the Vice mud-flap kit. Coating the body is a two-stage Line-X that uses an Ultra top coat for a sealed and easy-to-clean finish. While the color looks close to the military tan, it’s actually a Toyota color called Quicksand.

https://www.nittotire.com/light-truck-tires/trail-grappler-mud-terrain-light-truck-tire/

We got to check out the rig in action at one of our favorite southeast ‘wheeling venues: the Flats Offroad Park in Marion, North Carolina. While the stock 218AMG transfer case is still splitting power to the Torsen differentials, the rig worked surprising well. Despite not have a tremendous amount of suspension travel, the width and immense ground clearance helps it to excel off-road.

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While it’s hard to consider any purpose-built military vehicle practical, Odell has done an excellent job of adding refinement to the HMMWV platform. Sure, you could start off with a civilian H1 Hummer and have a slightly more refined setup out of the gate. However, the price of entry of an H1 can easily be triple that of what you would pay for an ex-military HMMWV.

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Fun Fact

In an effort to shed weight, the body of the HMMWV is comprised primarily of aluminum. The massive hood is made out of a sheet molding composite, making it similar, but stronger, than ordinary fiberglass. This creates a very light overall weight, which is one of the reasons Odell nets over 20 mpg with his setup.

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Be sure to check out more of the build in the photo gallery below. After that, check out this one-of-a-kind Cummins-powered Chevy Colorado. 

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