1. Motor Oil.
It is always a good idea to have a can with a few litres of engine oil as a backup. Even if you are confident that the oil should last you for a good drifting session, just a small leak can result in a major loss of oil. Along with this, racing on the track and drifting corners significantly burns through the engine oil, so it is smart to have oil ready, to top-up if necessary. Ideally, a good engine oil should maximize fuel economy as much as possible, and many engine oils already contain additives such as dispersants and detergents to keep the engine clean and running smoothly.
2. A tire pressure gauge and a portable tire pump.
Through the heavy friction that is put on the tires during racing, the air in the tires heats up and expands, causing fluctuations in the tire pressure. This friction can be even greater when turning corners and heavy braking. This is why it is good to have a tire pressure gauge and a portable tire pump on hand for adjustments.
3. An extra set of wheels with tires.
This goes hand in hand with the last point as, if you do happen to blow through a tire, you will need a backup. This includes not just the tires, but also the actual rims of the wheels. This is also important if you are driving the same car home after driving on the circuit, as the car must have safe and road-legal tires.
4. Car jack and ramps.
A car jack is essential for lifting up the car to check the inner tread of the tires. Even though a car jack is great to have a quick check underneath the car, if you think you may need to do a bit of work under the car, an axle stand is a safer option. If you are driving a very low-riding car, you may also need a small set of ramps to be able to elevate the car to get the jack underneath it.
5. Other fluids.
This includes brake fluids, transmission fluids, power-steering fluids, gear oils and any other oils you might need to lubricate other parts of the car. An extra canister of fuel may also be a good idea to bring along, as driving full-throttle on the track significantly burns through fuel. Cleaners and degreasers, such as a good carburetor cleaner, can be useful to have on hand as well.