16
TUNING & SETUP TIPS
MAINTENANCE
FOLLOW THESE STEPS TO KEEP YOUR CAR IN SHAPE FOR RACING
THESE STEPS PREPARE YOUR CAR FOR MAXIMUM PERFORMANCE
DIFFERENTIAL
MAINTENANCE
You should rebuild the differential when the
action gets somewhat “gritty” feeling. Usually
cleaning the diff and applying new lube per the
instructions will bring it back to new condition.
Normally, as the parts seat, the diff will get
smoother. If, after carefully cleaning and
relubing the diff parts, the diff still feels gritty,
the 1/8” balls and drive rings should be checked
and possibly replaced.
DIFFERENTIAL
ADJUSTMENT
While holding both rear wheels with your
hands as shown, use your right thumb and
index finger to try and rotate the spur gear. The
spur gear should be very difficult to rotate. If
you can rotate it easily, then tighten the #4185
11/32” nut at the end of the axle,
a little at a
time,
until the spur gear is diffcult to rotate.
Your car is one of the most tunable on road cars
on the market. This section will try to explain the
parts and adjustments you can use to tune your
car for different track conditions.
CASTER
Caster describes the angle of the kingpin as it
leans toward the rear of the vehicle. As an ex-
ample, 0° of caster puts the kingpin in a vertical
line. Positive caster means the kingpin leans rear-
ward at the top.
T-BAR FLEX
Look at the back end of the of the T-bar at the "T"
shaped section. You will see there are three holes
which can be used to attach the T-bar to the lower
rear pod plate. You have assembled your car us-
ing only the two outermost holes. This setup will
make the rear suspension very active (soft) front-
to-rear. Your car will have more rear traction and
will accelerate through bumps better than if you
were using all three attachment holes. Try using
all three attachment holes when racing on smooth,
high traction conditions.
Use all three holes for smooth,
high traction tracks
T-BAR FLEX
Increasing the positive caster on your car
will slightly increase the steering into the corner
but it will slightly decrease the steering exiting the
corner.
Reducing the positive caster will decrease
the steering into the corner but it will increase the
steering middle and exiting the corner.
Your car has adjustable caster in 2° incre-
ments using the #8413 white caster shims on your
front end (see page 4 for view). With the IRS
caster blocks the caster can be adjusted as fol-
lows:
UPPER ARM PLACEMENT,
LEFT FRONT
Less aggressive
steering
More aggressive
steering
Less steering
More steering
Outer holes
Inner holes
Your kit comes with the adjustable
IRS front caster blocks. The caster
blocks have six different mounting
holes to achieve any steering feel
you need for any track.
The differences between the
outer and inner hole on the caster
block affects how aggressive
(steering reaction) the steering
feels. The outer holes have the most
aggressive feel as you move the
arm to the inner holes the steering
gets less aggressive.
Moving the upper arm up and
down you will achieve how much
steering your car will have. By hav-
ing the arm in the lower position you
will have the most steering as you
move the upper arm up you will start
decreasing steering. Use the diagram
to help you choose the arm place-
ment for your track conditions.
IRS adjustable
caster block
2 caster shims behind the upper arm = 0° of
caster.
1 shim in front and 1 behind the upper arm =
2° of caster.
2 shims in front of the upper arm = 4° of
caster.
UPPER ARM PLACEMENT