STEM AND Outdoor KArting

Outdoor Karts (10-12)

Outdoor go-karts are unique in motorsports since they have a solid rear axle. Because of this, for a kart to corner freely, the inside rear tire must lift off the track. Lifting too late, dropping too early, or not lifting the tire is the same as stepping on the brakes.

The location of the center of mass is one of the most overlooked factors in cornering. Experimenting with It requires the complex and time-consuming task of moving the kart seat and ballast.

Since I require 75 lbs of lead to make race weight, it was easy for the center of mass on my outdoor kart to start too low. Once I raised the center of mass far enough to assist with the tire lift, I could drive at the speeds required to compete.

Dynamometer (12)

I use a dynamometer to compare engine components to see which engine block, cylinder head, and carburetor combinations generated the most horsepower at the crankshaft.

The readings gave us horsepower, and torque curves plotted against RPM.

My LO206 motor gained significant hp simply by swapping between factory-legal parts to find the best combinations!

Data Logging & Analysis (10-12)

Data from the track tells us what adjustments to make in the pits.

Data logged

Lap number
Lap times
GPS position
Speed
Elevation
G-forces
Engine RPM
Throttle position
Brake fluid pressure
Synchronized video
Date and time
Track name
Driver name
Kart designation
Race type (Practice, Warm-up, Heat, Final)

Data analysis

Am I consistently driving the best line?
Am I getting the most out of the tires and frame setup?
Is the frame setup correct?
Is the gearing proper?
Am I on and off the throttle and brake correctly?
Are my actual lap times approaching my theoretical best?

Ride Tuning (10-12)

Ride tuning adjustments

Caster, Camber, Toe, Ackerman, and Steering Sensitivity
Track width
Wheel material, air volume, and offset
Hub material and length
Ride height and angle
Torsion bar settings
Wheelbase (axle to axle distance)
Tire type, wear, and air pressure

Carburetor Tuning (10-12)

It's all about maximum airflow with the correct air-fuel mixture.

Sensors are used to collect Engine data

CHT - Cylinder Head Temperature
WT - Water Temperature
EGT - Exhaust Gas Temperature
AFR Stoichiometric Exhaust Sensor
Tachometer

Weather data is also taken into consideration

Temperature
Relative Humidity
Barometric Pressure
Air Density

Adjustments made based on data analysis

Jet Size
Idle Setting
Air Fuel Mixture
Float Height
Radiator Air Flow

Weight, Balance, and the Center of Mass (10-12)

Moving weights and the seat around my kart allows me to fine-tune the overall weight, the front/rear balance, and the center of mass.

At home, I use four bathroom scales at the corners of the kart to calculate weight, balance, and center of mass.

With some arithmetic, I can determine my overall race weight (my kart with me)
With a bit of algebra, I can calculate my center of balance
With a bit of trigonometry (and lifting one end of the kart), I can calculate my center of mass

Pictured here is the scale used during competition to see if you made weight at the end of a race. I'm in the LO206 Light Class (345 lbs) and weighed in at 348 lbs, with just 3 lbs to spare, or within 1% above the target race weight. That's about as close as you can get to the right weight after a race.

Adapting My Kart to Fit (10-12)

They don't make adult karts or very much racing gear to fit small women.

I've had to make several significant modifications to my kart to accommodate my body safely:

Lower and extend the steering column.
Install a pedal mount tray to move the pedals 3 inches higher and 6 inches closer to the seat.
Install a smaller-than-usual seat, raise it, and move it forward to reach the pedals and steering wheel.
I've had to pad the sides of the seat to fit my narrow female rib cage.
Replace the 3-gallon fuel tank with a 1.5-gallon tank, so I don't bruise the inside of my knees.
Add up to 75 lbs of lead to make racing weight.