Enduro Racing - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

U.S. Racers compete on ice ovals, three eighths to one mile in length, and travel 150 to 500 miles
non stop. The races take approximately two to eight hours depending on the course and conditions.
Driving is usually shared by two or more drivers but change is not mandatory and some racers
prefer to run the distance unassisted, fuel and maintenance stops give the racers short breaks or
time to switch drivers but many times the engines are never stopped during the entire event so the
action never stops. Like auto racing, caution flags often come out to slow the pace while mishaps
are tended to or for track grooming. As many as 35 sleds may be on the track at one time which
keeps the action fast and furious.
The racing machines resemble F-111 type sleds and Michigans M. I.R.A. uses many ISR F-111 rules.
However many cross country techniques and strategies are also used because of the length and
rugged nature of the races. To prepare a machine for this type of racing one would combine a cross
country sled with a Formula Ill sled.
The engines may be up to 600cc in size and are usually modified to various degrees. Some racers
prefer highly modified engines for maximum HP, others prefer milder engines for reliability. Either
way, the engines are many times lowered in the chassis for a low center of gravity. The suspensions
are usually lowered or shock travel limited to further lower the machines much like oval racers.
However during long rough races like the 500 in Sault Ste-Marie, full travel is sometimes best. As
with cross country racing the high stress parts of the machines must be reinforced. The ice ovals
exert tremendous forces on front end components, especialy when the maximum of 13 gallons of
fuel is on board and the track gets rough.
To determine the starting grid for an endurance race; qualification, heat racing or timed qualifications
usually run the day or days before the race. A racer should have his engine and sled in a
qualification mode to ensure a spot on the starting grid. At Michigan's "500", as many as 70 teams
may try to qualify for the 35 positions available. Competition is fierce for these 35 spots and
requires a much different strategy than race day.
The machine should be low, light, and sharp with high HP engine components. Many racers use
"qualifying" cylinders, pipes, carburetors and clutching, then switch to a milder state of tune for
the long race. This requires that mechanics and tuners be able to tune two completely different
racers and can be very stressful. Many teams will qualify with chassis very low. For better
cornering in smooth ice then switch to more travel to soak up the big bumps on race day. This
requires knowledge of the sleds handling characteristics in both modes. Testing is the key here;
many hours of testing.
During the race, drivers must pit to take on fuel, change carbides, switch drivers and perform any
other maintenance required. This requires a very organized pit crew. A crew chief will constantly
analyze the race progress and conditions and make necessary decisions on when to make repairs
or adjustments. Constant communication with the driver by hand signals or radio keeps everyone
informed as to the situation of the race. The pit crew must be very knowledgeable of the machine
and must practice the adjustments or repairs which will be encountered during the race.
Personal training and conditioning is also a must for the serious enduro racer. A fatigued driver
has no business on an ice oval with 30 fellow drivers in pursuit. Everyones safety is at stake and
should be taken seriously.
a well prepared team can be quite successful.
Section COMPETITION PREPARATION
07
07-21