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Anatomy of a Monster Truck

Posted in Features on February 1, 2013 Comment (0)
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Bigfoot 18 is the newest monster truck to roll out of Bigfoot 4x4, Bob Chandler’s Magic House of Horsepower in Hazelwood, Missouri. With over 30 years of building monster trucks on his resume, it’s a known fact that Chandler and his team know a thing or two about building world class, race-ready trucks, and the newest Bigfoot is a snarling animal.

Bigfoot 4x4 started with a “clean sheet of paper” when they designed Bigfoot 18. The truck has a 1,580 horsepower, mid-mounted, supercharged big-block on alcohol that produces sick, nail-you-to-your-seat acceleration. The high-tech, long-travel suspension is designed to quickly settle the truck down after mega big-air landings. As important, the suspension is also engineered to withstand the repeated abuse that is typical of monster truck racing (sometimes the landings are equivalent to being dropped from a three-storey building). The truck is also designed for quick serviceability (rounds of racing come hard and fast and downtime can translate to a loss) and safety for the driver and spectators. On top of it all, literally, is a sexy fiberglass Trophy Truck race body, and Bigfoot says that when the truck was introduced, it was the first body of its kind on a monster truck.

In the relatively short time Bigfoot 18 has been in existence it has made quite a name for itself. Example? While behind the wheel of Bigfoot 18, long-time Bigfoot pilot Dan Runte reclaimed the Guinness World Record for the longest monster truck long jump. It happened in Indianapolis, Indiana, last September and the truck flew an amazing 214 feet, 8 inches. And it stuck the landing.

We caught up with Team Bigfoot at the 15th Annual O’Reilly Auto Parts Ozark 4-Wheel Jamboree Nationals in Springfield, Missouri, and they were kind enough to let us crawl around their newest machine. Turn the page for a look at what makes Bigfoot 18 one of the most advanced and rugged monster trucks in existence.

Rear axle
ZF model APL-B765, ZF 2-inch-diameter double-cardan axleshafts, ZF limited-slip differential, 2.37:1 center differential ratio, 6.4:1 planetary ratio, 16.192:1 final ratio, custom Bigfoot 4x4-made four-link mounts (extra beefy), custom Bigfoot 4x4-made billet knuckles that are ambidextrous (they can be mounted on either side of the axle)

ZF internal planetary-mounted three-disc wet brake

Electric-over-hydraulic steering with a modified ZF third-member-mounted double-ended ram (ram and tie rods located behind axlehousing, high on the axle above driveshaft), tie rods made from 2.5-inch-diameter, 0.250-inch-wall DOM tubing, fitted with Aurora spherical rod-ends

Chassis/safety
Concussion Motorsports chassis, made from mostly 2-inch-diameter, 0.120-wall DOM tubing and 2-inch-diameter, 0.156-inch-wall DOM tubing, customized by Bigfoot 4x4

Three front-mounted electric pumps (two are for the rear steering and one is for the braking system)

Front-mounted JAZ 22-gallon metal fuel cell with plastic bladder

Cable-activated 10-pound halon fire suppression system with multiple ports, cockpit-mounted 2.5-pound handheld fire extinguisher

Remote ignition interrupter radio system (allows the vehicle’s electrical system to be shut down remotely via radio)

Engine/transmission
Ford 572ci V-8, mid-mounted (for weight balance and ease of maintenance), aft-facing

Enderle fuel injection

BDS 871 blower

Three Odyssey PC1500 batteries, charged daily, no engine-powered alternator

Dyno-rated at 1,580hp @ 8,500 rpm and 1,250 lb-ft of torque @ 4,200 rpm

Abruzzi two-speed Powerglide transmission, Neal Chance Racing Converters torque converter with 3,500 rpm stall, manual valvebody, B&M shifter

Cooling system
Rear-mounted Griffin single pass radiator with 15-inch-diameter electric fan (set up as puller fan so hot air isn’t blowing on the injector hat)

Rear-mounted Flex-a-lite transmission cooler with 10-inch electric fan

Tires/wheels
Firestone 66x43x25 ag tires, buffed and hand cut to reduce weight (they shave off about 200 pounds per tire) and improve traction

Steel 25x38 custom wheels

Weight of each tire/wheel combination: approximately 700 pounds front, 800 pounds rear

Transfer case/driveshafts
Divorced Pro Fab Quick Change aluminum four-gear transfer case (because the engine is aft-facing and the rotation of the transmission output shaft is backwards in relation to the T-case and axle rotation, the Pro Fab unit corrects the driveshaft rotation), underdriven (ratio dependent on track), with direct-drive coupler

Custom 3.5-inch-diameter driveshafts made from 0.093-inch-wall DOM tubing, 1480 series U-joints, custom driveshaft restraint system that is designed to function while offering a full range of motion as the suspension cycles

Interior
ISP seat, custom fit for driver Dan Runte

Grant quick-release steering wheel

Auto Meter Pro-Comp Ultra-Lite gauges

Clearly marked electrical connections, buttons, and knobs

Aluminum and Lexan floor

Center-mounted rear steering control switch with rear steer re-center button on the transmission shifter

Suspension
Four-link, link bars made from 2.5-inch-diameter, 0.250-inch-wall material with Aurora spherical rod-ends that have a heat-treated body, race, and ball.

Bigfoot 4x4 designed-and-built four-tube hydraulic-over-nitrogen bypass shocks (two per wheel, one compression, one rebound), Sway-A-Way bumpstops (four-inch-travel front, six-inch-travel rear).

Sway-A-Way 2-inch-diameter antisway bars, Bigfoot 4x4-designed link arms, Aurora spherical rod-ends with heat-treated body, race, and ball.

Limiting straps, 31-inch-long front, 36-inch-long rear

Wheeltravel is 25 inches front and 30 inches rear

Front axle
ZF model APL-B765, ZF 2-inch-diameter double-cardan axleshafts, ZF limited-slip differential, 2.37:1 center differential ratio, 6.4:1 planetary ratio, 16.192:1 final ratio, custom Bigfoot 4x4-made four-link mounts (extra beefy), custom Bigfoot 4x4-made billet knuckles that are ambidextrous (they can be mounted on either side of the axle)

ZF internal planetary-mounted three-disc wet brake

Hydraulic steering (uses an engine-driven pump) with a modified ZF third-member-mounted double-ended ram (the ram and tie rods are located behind the axlehousing, high on the axle above the driveshaft), tie rods made from 2.5-inch-diameter, 0.250-inch-wall DOM tubing, fitted with Aurora spherical rod-ends.

Body
Bigfoot 4x4-customized FiberwerX Ford F-150 Trophy Truck fiberglass body

Hot Hues Blue Mood paint, airbrushed details, hand-pinstriped

About This Series
This is the first installment of the “Anatomy of a…” series. In this occasional series, we’ll take a look at the tech (or lack thereof in some cases) that’s integrated into four-wheel-drive vehicles that we may not normally feature. Some of these vehicles are packed with tech, others may be surprisingly simple, and some may have unique features that are specific to their type of wheeling.

Bigfoot 19 and 20
As we were writing this story back in September, Bigfoot 4x4 was in the process of building their newest trucks, Bigfoot 19 and 20. Bigfoot 19 is the team’s newest race truck and Bigfoot 20 is the world’s first electric monster truck. More info can be found at www.bigfoot4x4.com.

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