The Science
The most important two ideas for the teams to consider were torque and traction.
Torque is another name for turning force. In a car, torque is what the engine produces to turn the wheels. More torque can be sent to the wheels in first gear than in fifth gear because first gear has a larger gear ratio by which to multiply the torque.
With two engines, used in a low gear, the Turbo Taxis had more ability to keep pushing against the Subs' vehicle.
However, having a monster engine is no use unless you have traction. Traction is a term used to describe the friction between a moving item and the surface it's acting on. In our sumo cars case it was important to have lots of traction between the car tyres and the tarmac skidpan.
Factors affecting the amount of traction include: the properties of each surface (are the tyres slick or do they have good treads?); how much force of contact there is (this is why both teams tried to make their vehicles as heavy as possible); and area of contact (in this case the size of the tyre, which both teams increased by letting down their tyres, making them wider).
Oil or water on a road also has an effect on traction, which is why we thought it would be interesting to see what happened when they had to sumo battle on wet tarmac.
Overall, the Taxis made the machine with better torque and better traction, so they found it easy to push the Subs' vehicle out of the ring.
