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The Exhaust System
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| The DC Subaru STi exhaust on the left flows a lot better than the stock exhaust on the right. |
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| This Magnaflow performance cat flows well and does not reduce power very much. It still functions to reduce emissions. |
The exhaust system is simply the tubing that directs burned exhaust gases away from the motor. The exhaust system consists of the exhaust manifold, the catalytic converter and the exhaust pipe. The manifold collects the exhaust gas from each individual exhaust ports in the cylinder head and collects them into a single pipe. This pipe leads into the catalytic converter where poisonous constituents of the exhaust gas such as Oxides of Nitrogen (NOX), various unburned hydrocarbons (HC) and carbon monoxide are converted to non-toxic CO2 and water vapor. After the catalytic converter, the gases flow into the exhaust pipe where they pass through the muffler which reduces the noise to an acceptable level and out into the atmosphere.
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| The stock cast iron exhaust manifold is designed for economy, compactness and emissions before power. |
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| Headers are designed to have better flow and sometimes to exploit pulse tuning. |
Although not directly responsible for motivating your ride but nevertheless deserving an honorable mention as critical parts of a motor are the engine’s cooling and lubricating systems.
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| ARC makes high quality high performance radiators. |
The cooling system circulates a mixture of antifreeze and water throughout the block and head keeping them from getting too hot from the continuous explosions that they are subjected to internally. The water is pumped out of the block to the radiator, which is a heat exchanger located in the very front of the car, to be cooled down and re-circulated back through the engine. A faulty cooling system can wreck a motor very quickly by letting it overheat. Although this sounds very basic, my neighbor almost ruined his motor by driving around for several days with his temperature gauge pegged when his radiator sprung a leak. He really did not know that overheating will surely destroy an engine very quickly. The fact that his Integra still runs pretty well once he fixed the radiator is a strong testament to the bulletproofness of Honda engines.
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| Most modern engines use a gerotor type oil pump where this gear like positive displacement impeller can move oil at high pressures. |
The lubrication system is a pump which delivers oil to all of the engines bearings located on the crank and the valvetrain. The pistons and rod wristpins usually rely on splash that is created as oil is flung off the rotating crank. One of the quickest ways to ruin an engine is to run it out of oil. My neighbor’s older brother almost trashed his Acura Legend’s engine by doing this once. He did not realize that periodically you must check the oil level, and ran the engines oil supply down to nothing. Fortunately he asked me what the oil pressure warning light meant, and we caught the low oil level before any damage was done. Don’t laugh, the only reason that I, a supposed expert, know this stuff is that it was drilled into my head by my engineer father. My neighbor’s father owns a restaurant and does not work on his car at all. He doesn’t work on cars and my Dad cannot cook awesome Chinese food.
Now that you know what all of the basic parts of an engine are and what they do, it’s time to understand how they work together in a system. We will get into that in our next segment of Suck Squish Bang Blow.
