Demolition Derby Tech

Demo derby cars

Demolition Derby Tech Part 1

A Tech Look Inside the Disposable Motorsports Machine

by Mike Kojima and Aaron Guardado

Although you might think that Destruction Derby is the simplistic smashing of cars, it is actually a pretty sophisticated formula with an evolved set of rules that allow a high level of safety and competitiveness with a very low cost of entry.  Destruction Derby has a rich history dating back over 50 years and the rules and regulations have evolved continuously since then.  Let us discover what is inside a typical car preped to the maximum level of the rules.

The object of a Destruction Derby is pretty simple, you smash your car into others until either your car or the others stop running.  You must make contact every two minutes or your are disqualified.  The last car running is the winner. Destruction Derby has tactics, it is better to use the back of your car to hit your opponents so the engine and radiator will be spared damage.  Big tough old American made cars are the vehicles of choice with station wagons being the preferred weapon.

demo derby tech
Like any motorsport, Destruction Derby requires a lot of prep to build a safe and reliable car that can go the distance under difficult conditions

 

Demo derby window screen
 All of the glass must be removed for safety.  This sturdy metal mesh and reinforcing bars prevent the hood from coming back and decapitating the driver.  It also prevents injury from other flying parts striking the driver

 

decklid chains
 The rules prohibit welding the trunk lid shut which would be good if it were allowed under the rules, but the trunk must be chained shut for safety

 

hood chains
 The hood must be safety chained shut as well, the chains have to be easily detachable to work on the engine

 

Although the engines are really pieces of crap, they are tuned to run well and have good throttle response.  The engine is given a good tune, the accelerator pump shots are increased and the timing is advanced. The engine and transmission have to run and shift well so the car can go forward and backward without stalling or hesitation.  Being immobile is death in destruction derby.  Some serious teams have favorite drivelines that they switch from car to car.  It is also advisable to have auxiliary shift and accelerator linkages so you can still move in case your primary linkages are damaged by impacts
The fire extinguisher is mandatory safety equipment and it is advisable to relocate the battery to the inside of the car away from impacts.  Auxiliary grounds are advisable as well
 A simple fuel cell is mandatory safety equipment, important when the car is going to be smashed to hell

Although the rules differ slightly from locale to locale, they are also quite similar as well.  If you are going to build a car, be sure and check your local tracks rules.  At our location, chassis reinforcement is illegal as is welding up your differential for more traction, both good ideas if its legal in your location.  Welding the doors, hood and trunk lid shut is also illegal at our track as that will significantly strengthen the chassis.  Relocating the radiator is also not allowed.

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