Set up tips for racing scale drag cars.

MOTOR: As in full size drag racing your chances of winning are less if your motor isn’t as good as it could be.
To have a top performing car in heads up racing where the motors are controlled eg; Super 16D motors as used in the Box Stock and Hard Body classes you need a top performing motor.
If your motor revs high, quickly and smoothly look after it by keeping it clean and lubed, if it doesn’t perform well, fix it or replace it.

CHASSIS: In order for a car to run well it needs to run straight, sounds fairly simple but there are a few things that can prevent this from happening.
The driving axle needs to be exactly 90 degrees to the direction of travel , a poorly aligned or bent axle will cause the axle not to revolve on a single axis and therefore develop a vibration within the chassis and cause the car bounce off the line, as will wobbly wheels and any loose or worn axle bushes etc.
The slot should be evenly centered between the driving wheels when viewed from above , so the car leaves in the exact line of direction required rather than a general direction.
The wheelie wheels also need to be parallel to the driving axle and with an even gap under each wheelie wheel of approx .3 to .5 mm, so that when they touch the track they don’t impose an uneven load on the chassis which may cause the car to change it’s direction during the launch .

TYRES: The size of the contact patch is critical to the level of traction.
Slix that are too wide can cause the motor to bog , as they increase the load.
Slix that are too narrow can cause wheel spin as the motor quickly peaks but time is lost due to lack of acceleration.
Wobbly tyres can cause the chassis to bounce and the car will loose traction instantly.
The slix actually work as a clutch, too much grip = no slip which may cause the motor to take too long to peak, gearing that is too high can also have the same effect.
The slix need to slip just a little to allow the motor to peak quickly, but if they slip too for too long the car will loose time due to wheel spin , not enough slip and the car will also be slow to get to high revs, similar to driving with the hand brake on.
Higher powered cars may need a thin film of goo all the way down the track, otherwise with more power they can loose traction as the slix expand during a run.
Narrow slix and goo is quicker than full width slix without goo. 

GEARING: This is important as a car with a good motor, slix and a well set up chassis may still not reach its full potential if the gearing isn’t sorted.
Gearing that is too low will help the car to blast off the line quickly but as the motor peaks, the car will stop accelerating and just keep it’s momentum down the rest of the track.
Gearing that is too high will increase the load on the motor which will slow the car for the first part of the run.
A balance between the two is required to allow the car to leave the line quickly and accelerate till near the end of the track for  quick E.T’s.
It is important to note that the “ blast off the line ” sets up the car for the rest of the run, so slix size and goo levels should be sorted before working on gear ratios. An easy way to know if your car is close to the right gear ratio is to gear it so that the motor reaches top revs about 6-8 feet from the finish line. If the car revs well at no load ( free revving ) and peaks near the end of the track, testing of different gear ratios with an accurate timing system may get the car to run quicker.

WEIGHT: As long as your car isn’t too much over the minimum weight for the class that it runs in, don’t worry as cars that are not dead on the minimum weight can still be top performers if the rest of it is set up well.