Chevyboosting....

MAW's site has some good info AND brings up an important fuel injection fact that should be repeated here for those new to injection: The opening of the trottle blade(s) lets a certain amount of air into the engine just like the carburetor butterflies do. However, in a fuel injected world, some calculation has to be done regarding the amount of fuel to squirt for that particular amount of air. The computer makes the calculation. There are two methods used to measure the amount of air: speed density and mass air flow. The speed density method measures the incoming air temperature and pressure to calculate density. Also, the air speed thru a given opening is inferred by the trottle position and vacuum. The mass of the air is calculated.

For mass air flow, usually they use a heated wire in the inlet tract. It takes a known mass of air to cool the wire a certain number of degrees and the wire resistance is proportional to the temperature of the wire so the mass of the incoming air can be calculated.

Either method works, Chevy and Ford seem to bounce back and forth on which method they use. However, the important thing to learn is that there are components used on one method that are not used on the other.....like the hot wire used on mass air flow but not on speed density. Get familiar with your particular type and make a list of all of the components and their abbreviations. Soon, it will become simple to understand what each does and how they all work together.