Understanding car engine performance

I have a lot of automotive books in my house and namely Nissan manuals, Toyota, Mitsubishi, Mercedes Benz, Honda and some mechanical books that serves as references. I arranged them one by one in my shelf so that I can locate them and easy to find. Car engines are all the same based on my experience because they all have the same system. They just vary on some features because some have added features like for Mitsubishi engines, it has turbo device that provides a constant air to its intake manifold while some have no device like this. There are also engines that have a intercooler device to provide cooler air before entering into its intake manifold that the combustion chamber needs and some has an EGR (Exhaust Gas Recirculating). This type of device is just like an ordinary tube connected from the exhaust manifold back to its intake manifold. This device is responsible to gather all the unburned fuel from the combustion chamber and deliver it back to intake port for an air/fuel consumption. Diagnosing a car performance is so simple as long as you really know its proper uses because all parts of the car engine even the tiniest part has a certain thing to perform.