The sledge hammer: no compromises

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I At some point when converting an off-road vehicle, the point is reached where the effort for even better performance no longer justifies the benefit. Joachim Güppner experienced this first hand with his hardcore car, which had been created from a Jeep Cherokee over many years. The competitions attended became more and more intense, the upgrade work more and more complex. When the finally mounted 39er Bogger tires developed an insatiable hunger for axle innards, Joachim pulled the emergency brake. Instead, he started the Sledge Hammer project.

An all-American off-road buggy

Core idea: Take an engine with plenty of power, axles in the unbreakable category and build a car around it. And since Joachim is a proven USA fan, the source of the parts was also certain - the Sledge Hammer was supposed to be an all-American off-road buggy. Centerpiece: a 454 Chevy big block, target output beyond 400 hp. The Rockwell axes originate from large military equipment. They are usually installed in the six-ton ​​REO truck and, with the characteristic horizontal differential with angular drive, are an interesting alternative to portal axles due to the large ground clearance. In the American off-road scene, the Rockwell axles have earned the reputation of being absolutely indestructible, many tuners offer conversion kits for disc brakes and modified differential covers, for example.

Indestructible axles, huge tires

Large axles, large tires: after the conversion (drum brake system out, central disc brake in), the Rockwell axles with 44er Bogger were converted to 16.5-inch Beadlock rims fitted - just milling out the Bogger profile occupied Joachim for four days.

The project was based on the subframe, which was laid out on a three-meter wheelbase and initially accommodated the engine and axles. The rest of the buggy structure was then gradually adapted to this self-welded tubular frame. It was important to Joachim that the Chevy V8 be placed low and far behind the front axle in order to keep the center of gravity low. The rear axle is also steerable, both axles are controlled by a fully hydraulic steering from PSC Motorsports. There is no steering gear, instead a hydraulic cylinder takes over the work. The rear axle of the sledge hammer is turned using a lever. Not only can the steering be activated for each axle, the brake system with the central discs also has two pedals for optional use.

LPG instead of fuel: the sledge hammer runs on gas

Instead of petrol, Joachim relies on an LPG gas system that sits on the intake manifold instead of the injection. Two propane bottles in the rear share the space with the engine, oil and steering cooler. The batteries are also located in the rear box behind the seats. The axle suspension and damping are carried out by air struts from Sway-A-Way. The infinitely adjustable spring /damper elements provide a tight 45 centimeters of spring travel - it is clear from the start that the twisting of the sledge hammer will be quite severe.

After the construction was completed, the entire car was dismantled again to provide the self-made frame with a powder coating. The final construction of the shiny red metallic Sledge Hammer with the last sheet metal work, cabling and a thousand small adjustments took a complete winter season.

Serious setback during the first test run

What actually happened was a serious setback: The 7.4 liter Chevy engine acquired from a tuner turned out to be a blender - with a whitewashed crack in the block and sloppy construction work that cost a piston and a connecting rod their lives in the first test run. So keep an eye out for an engine again, convert it again - with success: eleven months after the start of the project, the Sledge Hammer completed its first extensive test drive in Saverne and has since been allowed to show what it can do in the freestyle trial series, various trophies and private rides plugged.

Joachim granted his Sledge Hammer a last update a year later: A 496 cui V8, which with a displacement of 8.1 liters truly deserves the name 'Big Block', replaced the 454 Chevy. The monster eight-cylinder not only makes music, it also delivers power: the measurement showed 460 hp and 860 Newton meters. That's enough even for Joachim's claims.


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