The level of voltage being supplied from the battery helps determine the degree of heat of the spark plug. Teams that run without alternators run the risk of having low voltage in the system, resulting in a cooler spark. A minimum of 11.5 volts should be maintained to the coil so that the spark will generate sufficient heat needed to completely ignite the mixture. The engine will run at a lower voltage than that, but a number of negative issues may arise that decrease your engine's horsepower.

Plug and Coil Wire Efficiency
There are a couple of tricks that involve the spark plug wires that supply the energy to ignite the air/fuel mixture in the engine. The first important issue is the quality and size of the wire. It goes without saying that the better wire you run, the better ignition you will have.

It's important to keep the length of the ignition wire from the coil to the distributor as short as possible-under 18 inches, preferably at or around 12 inches. It is the same with the plug wires, i.e., the shorter the better. Line loss, which is a loss of energy when electricity flows through a wire, decreases the heat generated by the spark and results in a less efficient burn of the air/fuel mixture.

The plug wires that are routed to cylinders beside each other in the firing order should be crossed to eliminate interference. High-energy wires that run close together and parallel will pick up the energy from each other unless the field is broken by crossing the wires to form an "X." In a GM V-8, the fifth cylinder fires just before the seventh cylinder, and they are next to each other. Those two plug wires need to be crossed.

Oil Temperature Generates Horsepower In any internal combustion engine, heat is horsepower. All of the elements of the engine must contribute to the overall operating temperature of the engine. The oil that flows through the engine is a source of retained heat and must be maintained at an optimum temperature.

As the oil becomes hotter, the engine will actually generate more horsepower. For circle track racing applications, the oil temperature should run 220 to 230 degrees. Modern synthetic oils will stand temperatures upwards of 300 degrees, and most high-quality "standard" engine oils will sustain comfortably in the 230-degree range. To a point, the hotter the oil, the better the engine will run. With modern components, and the way race engines are assembled, there should be no problems with the higher oil temperatures listed.

Proper Oil Filtering
An item unrelated to horsepower and more appropriately related to the survival of the engine is the filtering of the oil. The placement of the oil filter and accessory filters such as an Oberg filter is important for longevity. Having a ton of horsepower is of no use if the engine does not live long.

The Oberg filter is a screen and/or paper filter that is designed to catch larger-diameter particles after they leave the engine and before they are pumped back into the system. The filter should be placed just behind the scavenging pumps and in front of the reservoir can. It should be checked often for the existence of small particles that can mean a bearing is going bad or any other part is failing. In the event of catastrophic engine failure, the Oberg type of filter will catch large metal pieces.

The oil filter should be the last thing the oil passes through before entering the engine. The filter will prevent contamination from getting into the engine. The contamination could come from welding slag in aluminum oil coolers. Using old oil lines is another source of potential contamination. Never reuse old oil lines from blown engines because they may have pieces lodged in the lines. The lines are much cheaper to replace than a complete motor.