How to calculate the speed of a car with various formulas?

Question

Physics

The bottom line is that I need a number of formulas related to the calculation of data about the car:
1) Calculation of the speed of the car without knowing the time, while all other data can be obtained, such as acceleration speed, revolutions per second, etc.
2) Calculate the speed of the car in different gears
3) Fuel consumption 4
)
Acceleration

Answer 1

1) and 2) are the same. And it's simple math.
Multiply the gear ratios of the main pair and the selected gear, multiply the result by the engine speed - you get the wheel speed. All this is multiplied by the circumference of the wheel - you get the speed.
Circumference = Pi * D.
Approximate wheel diameter D (mm) = (rim size in inches)*25.1 + 2*(tire profile as a percentage of width)*(tire width)/100%
To be more precise, it is necessary to measure specific wheels on a specific car, and this value will even float a little depending on the air pressure in the tires. On some sports cars there are front and rear wheels of different sizes (not only on dragsters, not only on Formula cars), in this case you need to take the dimensions of the driving wheels (these are the rear, larger).
Well, at the end, convert to the usual units of measurement. Because the frequency was measured in rpm, the circumference in mm, and we want the speed in km / h (probably), and not in mm / min.
3) it cannot be calculated by formulas, it depends on many parameters (engine model, speed, load, fuel quality, engine wear, air temperature and pressure, engine temperature, compressor or turbine presence and boost degree; load in turn depends on speed, gear engaged, vehicle weight (taking into account the fuel in the tank, taking into account the weight of the driver, passengers and the contents of the trunk), the degree of wear of the transmission parts, tire pressure, "anger" of the tread and the degree of its wear, the quality of the road surface, the presence of a road slope ,... even a gust of wind will change the instantaneous fuel consumption depending on whether it is headwind or tailwind). The brains of the motor (ECM) always know exactly the flow rate only because they themselves give the command to the injectors every fraction of a second, how much fuel to inject now.