Sandblaster: Merchant Automotive’s Duramax-Powered Sand Drag Rail

Nick Beaudoin is co-owner of Merchant Automotive in Zeeland, Michigan. The shop’s not far from Lake Michigan, but more importantly, it’s just over an hour south from the Silver Lake Sand Dunes, a popular summer recreation area. While most people not familiar with the area will be surprised to hear that Michigan even has sand dunes, we can attest to their existence after driving and riding on them for some time. In fact, the state boasts 2,000 acres of dunes.

Growing up in the area, Beaudoin and his family frequently took trips to the dunes and spent many days playing and racing various buggies through the sand.

A 4-second pass in the mid 80s seems plenty fast when you’re sitting a just few inches above the sand.

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IDEAS-A-GRANDEUR

When it came time to build a new demo vehicle to promote Merchant Automotive, Beaudoin turned to his sand roots and commissioned a sand drag rail. But rather than just sponsor a car to keep their name in front of potential customers, the MA team wanted to build their own car and power it with the engine they’re well known to work on. Thus the idea for a Duramax-powered sand rail drag car was hatched. About a year later, they’re shaking up the sand box at every opportunity.

CHASSIS

The sand rail starts with a Mears Metal Products 2-seat mid-engine chassis constructed from 1.5-inch diameter chromoly tubing that forms the chassis and protective roll cage at the same time. The cage is powder coated MA orange while the aluminum body panels are contrasting black with orange and white graphics.

Since this sand rail is designed for drag racing rather than flying off the peaks of dunes, a short travel double A-arm front suspension hangs off the front of the chassis. Chrome-plated Mears Metal Aerostrut chromoly A-arms feature an aerodynamic shape fitting for the go-fast buggy. To tame the minor bumps in the sand, the front suspension uses a pair of Yarnell Specialties MS Cruisers shocks with polished aluminum bodies. A chrome-plated Stiletto manual rack and pinion steering box that connects directly to the chrome plated spindles handles the steering. Meanwhile, the front end of the buggy rolls on a pair of Goodyear Eagle 23.0X5.0-15 drag tires wrapped around 5-spoke forged aluminum Weld 15X3.5-inch spindle-mount wheels.

CONTROLLING THE BEAST

The sparse interior consists of a metal floor along with a padded aluminum bucket seat that forms the cover for the buggy’s electrical systems and fuel cell. Steering is handled by a small diameter D-shaped 3-spoke wheel with a quick release hub and a button to activate the transbrake. A B&M shifter with reverse lockout is mounted between the seats to allow Beaudoin or other Team MA Racing drivers to bang through the 1-2-shift as the car blasts down the 300-foot sand drag strip. A digital Racepack gauge cluster is mounted to the center of the roll bar horizontal cross-tube to make it easy for the driver to keep an eye on the buggy’s vitals.

Rather than run a single-seater, the MA crew chose to use a two-seat design so they can give rides to promote the company and their capabilities at events. Both driver and passenger are secured into the chassis with 5-point Simpson race harnesses for safety. The MA Racing Team allows passengers for exhibition runs but runs solo whenever they’re in competition racing the buggy. Headrest bosses are welded into the chassis tubes with fixed position headrests installed to keep occupants from getting whiplash as the buggy rockets off the line.

Releasing the hidden quarter-turn fasteners and tilting the seat forward reveals a small storage area that is filled with everything needed to make the buggy work: The driver side of the compartment holds a custom 4-gallon aluminum fuel cell that carries enough #2 pump diesel fuel for about twenty passes down the sand drag strip. The fuel filler can be accessed through the top of the compartment behind the driver and does not require removing the seat to be filled. A Racing Radios communication system is also installed above and to the side of the fuel tank, allowing the driver to speak with the passenger as well as his crew chief outside the car.

ELECTRONICS

The passenger side of the storage area holds a 6-pound Braille Green Lite Lithium Ion racing battery as well as the ground block and power distribution. The Duramax ECU and Racepack processor are mounted next to the battery with a FASS fuel pump mounted above them. In a weird twist, the electronic throttle for the LBZ Duramax engine is also mounted in the storage area next to the fuel cell. The MA crew securely mounted the throttle, then ran a throttle cable to connect it to the chrome-plated tubular steel throttle with toe-lift mounted to the floorboard of the buggy.

POWER TO SAND

In the rear of the buggy, Mears Metal Products built the chassis with a polished-aluminum Speedway Engineering quick-change independent rear axle in mind. The center section of the axle is securely mounted in the chassis with Fortin Racing 934 CV-joints and custom Mark Williams 300M gun-drilled axle shafts carrying the power from the ring and pinion to the wheels.

Three-point control of the IRS axles is handled with trailing arms on the front side, adjustable links on the backside and a set of polished Yarnell Specialties MS Cruisers shocks on the top. (Since we originally shot the buggy the team has replaced the rear shocks with a set of Afco double-adjustable coil-over shocks to help with chassis tuning).

To put the power to the ground and get the buggy moving through the sand, the team relies on a set of 34-inch tall Skat Trak Bigger Digger tires that were once a set of Goodyear Eagle 33.0X17.0-15 drag slicks. The tires are mounted to a set of Weld Racing forged-aluminum 15X16-inch Aluma Star 2.0 double beadlock wheels to clamp onto the tire and prevent the wheels from spinning inside the tire.

The NX bottle is mounted to the quick-disconnect wheelie bar to make sure that the buggy is never inadvertently run on the bottle without the wheelie bar installed.

SLOWING THE GO

Braking for the buggy is handled solely by the rear wheels with a set of inboard-mounted slotted rotors that sandwich between the CVs and the quick-change housing. The custom rotors are squeezed by a pair of 4-piston Wilwood Dynapro billet aluminum calipers fed through stainless steel braided brake lines. Brake pressure comes from a Wilwood pedal assembly and a CNC master cylinder, which allows the driver to whoa the buggy down at the top end of the track.

LBZ POWER

Unlike most sand buggies that are powered by air-cooled VW engines or V8 gassers, the 2,000-lb Merchant Automotive rail relies on an in-house-built 2006 LBZ Duramax engine for propulsion. Starting with a stock LBZ engine, the Merchant Automotive team disassembled and inspected the complete engine before beginning to build up the race engine. The short block still houses a stock crankshaft, but the balanced assembly now swings a set of Carrillo rods topped with a set of Danville Performance oval-bowl pistons through the stock cylinder bores. The block is secured in the chassis by custom-machined solid motor mounts welded to the frame and bolted directly to the engine block.

A set of stock LBZ heads top the block and are held firmly with a set of ARP head studs. Merchant Automotive push rods actuate the valves following the direction of the stock LBZ camshaft. A Melling oil pump handles oiling duties and benefits from a custom oil pan the team at MA fabricated to work with the chassis. The engine is kept cool thanks to a custom aluminum radiator with a pair of high-flow electric fans pushing air through the radiator. Coolant is circulated through the engine with a Deadenbear electric water pump.

Spent exhaust gasses are channeled from the cylinder heads through a set of stainless steel HSP headers. Exhaust pulses from the headers are carried to the Danville Performance 71mm VGT turbo by a set of HSP up pipes. Exhaust gases exit the turbo through a fabricated stainless steel tip that connects to the turbo with a V-band clamp and directs the gasses skyward. On the compressor side of the turbo air, is drawn into the charger through a large K&N cone filter with an Outerwear cover. An S&B intake housing was modified to allow the filter to mount between the turbo and the intake while still allowing airflow to be monitored by the ECU. After the intake charge is compressed, it’s fed directly into the engine through a fabricated intake bridge.

The FASS electric pump sends plenty of fuel from the tank to an Exergy 10mm stroker CP3 high-pressure fuel pump. From the CP3, fuel is handed off to a set of 100 percent over Exergy injectors that direct the fuel into the cylinders. A team at Duramax Tuner handles ECU programming to get the most out of the LBZ engine, while a Racepack Smartwire system data acquisition takes care of additional functionality.

To provide some additional oomph the MA Racing Team recently added a Nitrous Express nitrous oxide system to the buggy. It’s operated by the controllable logic of the Racepack Smartwire system, which monitors RPM, boost and throttle position to provide the nitrous to the engine. The NX bottle is mounted to the quick-disconnect wheelie bar to make sure that the buggy is never inadvertently run on the bottle without the wheelie bar installed. The MA crew estimates that the engine makes around 600 horsepower and 800 lbs-ft of torque on fuel only, and around 750 horsepower and 1,000 lbs-ft of torque with the giggle-juice.

The potent Duramax engine is backed by a 2-speed Power Glide transmission built by the team at Capizzi Automotive in Holland, Michigan, using a modified Allison bell housing to mate to the Duramax. Power is channeled to the built trans through a custom-built 13-inch torque converter. Internally, the Power Glide has been completely reworked to handle the Duramax engine, including a Coan Racing manual valve body and transbrake to help the big buggy stage, spool and launch just as quickly as any gassers that the buggy might be paired with at the drags. A transmission cooler and electric fan are mounted on top of the transmission to keep it cool while the team is hot-lapping the buggy with demo rides.

OFF ROAD TEST

After going on a ride-along in the passenger seat, I can tell you that this Duramax-powered buggy is one heck of a ride. Even with a passenger, the buggy regularly covers the 300-foot sand drag strip in under four seconds at over 80 MPH—if you ever get the chance to ride in it, don’t hesitate to sign up.

I also had an opportunity to slip behind the wheel and make a couple passes down the strip and can honestly say it’s an amazing sensation from behind the wheel where everything happens so fast: as soon as you leave the line, you bang a gear and in a flash you’re through the lights. While I didn’t come close to the current fastest time of 3.69-seconds or a top-end speed of 89 MPH, a 4-second pass in the mid 80s seems plenty fast when you’re sitting a just few inches above the sand! DW