Continuing past the turbo system, here you can see the business end of the engine's direct injection fuel system. The high pressure fuel rail feeds the injectors through stainless steel tubing before being injected directly into each cylinder. Tubing is required for high pressure direct injection systems because hose can't handle the required pressures, which can exceed 25,000psi. Also notice that there are no ignition coils, spark plug wires, or spark plugs. This is due to the fact that diesel engines use high compression to ignite the air-fuel mixture as opposed to the spark used in gasoline engines.
Mounted to the firewall of the SpeedSource Mazda are all kinds of goodies. On the left side are two high-end circular electrical bulkhead connectors for the engine electronics. The coolant expansion tank is just to the right of the connectors and in the center is the reservoir tank for the engine's dry-sump oil system.
The carbon fiber air intake duct feeds the air filter shown in the previous picture with air from just above the driver's head. The carbon fiber is laid up over a very smooth internal mold of the duct. This means that the inside of the duct where the air actually flows is very smooth, while the outside of the duct looks less perfect. I could have said ugly but let's be honest, carbon fiber on a true racecar rarely looks ugly.
Moving rearward of the engine is the remote transaxle-mounted alternator. Since the alternator is a heavy part composed of dense copper windings, mounting it just above the floor plate helps keep the center of gravity low. Also, the dedicated ducting to the alternator keeps it cool even though it is buried deep inside the chassis.
Proper airflow to all the components in a racecar is of utmost importance and the rear brakes are definitely no exception. Check out the carbon fiber duct work that just barely clear all the suspension components and rear axle. The attention to detail is what I like most. The part of the duct work that interfaces with the rear body work features a rubber seal to make sure all possible airflow actually makes it to the rear discs.