A Duramax-Powered Luxury Tank Built for Any Terrain
Thousands of off-road enthusiasts hit the desert, the trail or head up the mountain every day, but how many do it in a tank? The answer is very few. Better yet, how many do it in the fastest tank in existence? Only one that we can think of. It’s called the Ripsaw by its manufacturer, the Twister by its owner, and it’s practically unstoppable. Developed by Howe and Howe Tech (now under the Textron umbrella), the Ripsaw EV series platform was originally designed for military use, but has been available in consumer-based form the past several years. As for this civilian version’s off-road performance, it doesn’t stray very far from those initial battle-ready roots or in its off-road capability. With nearly two feet of ground clearance, 16 inches worth of suspension travel, 112-inches of track on the ground, a diesel-fired Webasto heating system, and an 800hp Duramax capable of propelling the 6-ton mini-behemoth to 65 mph, it’s the ultimate play toy.
The Ripsaw’s 800hp Heart
How exactly does this near-12,000-pound tank feel so light on its feet? It starts with the 800hp 6.6L Duramax situated behind the cabin. Built by Pacific Performance Engineering, a company that’s long familiarized itself with high-horsepower versions of GM’s common-rail V-8, the Duramax is overbuilt in virtually every way. Carrillo rods, valve-relieved, 15.5:1 compression Mahle pistons, and one of its Stage 1 camshafts reside in the short-block. Above the head gaskets sit a set of PPE’s Stage 1 heads, complete with CNC porting, a 5-angle performance valve job, and beehive valve springs.
Single Turbo & Dual Fuelers
A single Garrett turbo is tasked with building boost for the engine, and a ball bearing center section aids its responsiveness. Compressed air routes through an application-specific intercooler, fabricated by Ron Davis Racing, before entering the heads. A duo of CP3’s ensure rail pressure is maintained at all times thanks to PPE’s Dual Fueler system, with ported fuel rail fittings and one of the company’s race valves also being part of the equation. Oversized injectors built to PPE’s specifications conduct in-cylinder fuel delivery. A stand-alone engine harness handles communication duties, while an Xcelerator Hot +2 ET Race tuner holds the key to overall power output, with seven custom-tailored ECM calibrations to choose from.
When you’ve perfected the Allison 1000 the way PPE has, there is no need to reinvent the wheel—not even for a tank. Not only can the company’s proven Stage 5 six-speed automatic handle the 1,500 lb-ft of torque the Duramax sends its way, but it’s been fortified to withstand both the heft of the vehicle and the strain that comes with jumping it. Billet shafts are a big part of its fortifications, along with a billet C2 clutch hub and P1 sun gear. Other pieces in the Allison’s build recipe include a triple disc torque converter, additional clutches in the C1, C2, C3 and C4 clutch packs, and a recalibrated valve body.
Tubular Chassis & Floating Cockpit
To keep the Ripsaw’s handcrafted cockpit fully isolated from the terrain it’s covering, the cab is suspended via air springs (air pucks). Their inflation pressure can be fine-tuned courtesy of the tank’s onboard air compressor for a more comfortable ride or to stiffen things up should the terrain call for it. The chassis itself is made from fully welded, high-strength tubular steel. To make sure the tubular exoskeleton would hold up to long-term exposure to the elements and abuse, it was treated to both powder coating and then Rhino Lining.
Inside the cockpit is where things vary tremendously from a standard Ripsaw. In what is akin to approaching Ferrari with plans to alter its supercar’s interior at the OEM level, the owner asked the folks at Howe and Howe Tech if they’d be willing to allow him to add his personal touches while the Ripsaw was being built. More than receptive to the idea, the guys at Howe and Howe were both open to suggestions and willing to help put them into action. As a result, this particular version is just about as avant-garde as it gets. A redesigned dash with hand-sewn leather and integrated dual iPads, digital climate control, heated and cooled Recaro Sport Topline seats, a MoTec gauge cluster, Bose intercom system, Rockford Fosgate sound system, and interior RGB lighting all made the list. Then, to bring a fifth passenger along for the ride, a third retractable shoulder harness was added in the back of the cockpit.
“We haven’t gotten it stuck yet, but we’re working on it.”
Visibility is never an issue in the Ripsaw thanks to a plethora of lighting and camera options. A remote pop-up FLIR M625cs thermal camera provides unbelievable clarity at night, a backup camera and sensor system keeps things safe when maneuvering in reverse, and a 360-degree camera offers an unmatched, overhead view of all surroundings. As for illumination, countless ADAPT LED’s from Rigid Industries and the combination of five light bars turn night time into day. To zero-in on something specific, a pop-up Golight remote spot light is called upon. For a personal touch, an RGB lighting system is also onboard, with a million different hue variations on the table. Though it is in no way street-legal, the Ripsaw even has fully functional turn signals.
Suspension travel checks in at an impressive 16 inches controlled by the Ripsaw’s King Off Road racing shocks. There are three custom-valved, race-inspired shocks per side, which wear custom red anodizing. For bottoming control, two King bump stops, custom-anodized in black, are employed per side as well. With the drive line fully enclosed, the Ripsaw’s under belly resembles a giant, smooth skid plate, and the closest point to the ground measures 22 inches. As for drivability, it’s as advanced as it gets thanks to a state-of-the-art drive by wire system.
A Swiss Army Knife
At nearly 12,000 pounds fully loaded, the Ripsaw is a mini-behemoth, but thanks to the 800hp Duramax and 112 inches of track applied to the terrain it’s covering, it can dig its way out of virtually any predicament. But even though the Ripsaw is yet to encounter an obstacle it couldn’t overcome, there is plenty of extraction equipment onboard to keep things that way. A 17,500-pound Smittybilt winch is present out back, while a 9,500-pound unit is concealed up front. D-ring shackles, front and rear, are tied in with the chassis for added points of recovery.
Perfecting A Proven Platform
When the Twister project kicked off in the spring of 2018, no one knew exactly where the endeavor was going to go. But thanks to Howe and Howe Tech’s openness to suggestions, its ability to redesign things on the fly, and its willingness to allow a third party to personalize the vehicle during the manufacturing process, the customer’s needs were met and then exceeded. In the cockpit, it’s the Mercedes-Benz of tanks. Outside, it’s all business, with every single component serving a purpose. We’re told the goal for the Ripsaw was not only to build the ultimate off-road vehicle, but one that could travel hundreds of miles at a time, and last forever. Thanks to the Duramax/Allison combo, tubular exoskeleton chassis, and all the military-grade ingredients that’d already been proven in the field, that shouldn’t be a problem.