Do-It-Yourself High Performance Car Mods

Telling Which Adjustments the Engine Needs

If you were reading a set of directions and came to a line that just said, “Turn this knob,” your first question would probably be, “Which way am I supposed to turn it?” When tuning your engine, you will need to figure out if you need more fuel or less, and more spark advance or less. Sometimes there is an easy way to tell. For example, if you put on a set of fuel injectors that flow twice as much fuel, you will need to set them to open for only half as long. Usually, however, you will need other ways of checking.

The air-to-fuel ratio can be the simplest one to set, if you have the right tools. This is usually measured in terms of pounds of air to pounds of fuel. If you have 14.7 lb of air for 1 lb ...