Mechanics:

In addition to their organic parts, they have mechanical ones that could possibly be attached to their organic tissue. They have car batteries and engines. In Cars 2, we've seen Mater talk about how batteries power cars and how he has removed his friend Luigi's battery, which is terrifying if true. Does that mean that the Luigi flatlined? If yes, can they be easily revived if the battery gets reapplied? So, if batteries start-up cars, and therefore are the hearts of cars, what does that say about electric cars? Are they vegan? Does that mean the electric wires are the veins? What about sensors? Are they related to the nervous system? Cars feel pain through their outer shells and parts. How does oxygen work if the battery is the heart and is what starts the car? Do their lungs convert oxygen into electricity, which charges up the battery? The more answers we get, the more questions they pose. In terms of the functions of their engines, it isn't easy to describe. Since they can shift their gears, rev the engine, and train to max out their speed, it tells us that their engines can organically improve themselves, in a way. If they can train as humans can become faster and quicker, then that means their engines aren't fixed into a specific strict capacity of speed or power and can be enhanced through physical training. It makes little sense that they can't just upgrade their engines like they can with their outer-body modifications. In Cars 3, McQueen trains to beat electric cars, which inherently have a much better top speed and acceleration. It's the equivalent of having a shorter person compete against tall people in basketball. Unless the person gets surgery or genetically modifies their body to be able to compete, training might still put them at a disadvantage. So, training a car could enhance the engine because of the organic parts that improve, which could cause a boost in performance. But with things like engine upgrades, that would constitute a genetic or surgical procedure to enhance performance. This does mean that the open hood engine modification scene in Cars 2 is the equivalent of a heart surgery.