We are going into more detail on valve-event timing and how the spec of the rest of the engine affects optimal events.   This tech tip is from the full book, DAVID VIZARD’S HOW TO BUILD HORSEPOWER. For a comprehensive guide on this entire subject you can visit this link: LEARN MORE ABOUT THIS BOOK […]

Selecting a cam or, more accurately, deciding the cam events that the engine needs has traditionally been regarded as a black art. Most publications feed you just enough info for you to get into trouble (in most instances) or for you to decide you should let a tech guy at a cam company make the […]

The greater our success in terms of porting and increasing compression ratio and engine RPM, the harder it becomes to effectivly lightoff the compressed charge. Fortunately, improving the ignition is not a great challenge these days and, for the most part, not that costly either. But the situation has not always been so. Until the […]

As I have established, high-airflow potential, especially through the cylinder head, is a key element in producing power. If you are starting with as-cast parts, a means of reshaping them and testing the subsequent flow results are very useful aids to maximizing output. In short, the subjects in this chapter are physically porting heads, intakes, […]

We have finally arrived at the so-called cork in the system, as far as power production is concerned. As Chart 6-1 shows, optimizing airflow (and that means getting as much as possible) is the number-one goal. But as far as heads are concerned, it is not the only factor in making big power numbers. To […]

Let’s focus on the word “supercharge” for a moment. In the context of this book, it means to fill the cylinder above and beyond the displacement that it ordinarily has. For instance, if a cylinder has a 50-ci displacement and, by one means or another we cram 75 ci into it, then we can say […]

In prior posts, we looked at what was needed in the way of mixture quality and air/fuel ratios. Now our focus is the design of the intake manifold. Here, I discuss what it takes to minimize flow restrictions and optimize intake pressure waves.   This tech tip is from the full book, DAVID VIZARD’S HOW […]

So far, I have addressed ways and means of maximizing the air density delivered to the engine’s induction system. However, all this is to no avail unless the fuel is mixed with the air in a well-defined manner and to equally well-defined proportions.   This tech tip is from the full book, DAVID VIZARD’S HOW […]

We are dealing with an air breathing heat engine here, so let’s start off with the air our engine has to work with. At what we call Standard Temperature and Pressure (STP) conditions, atmospheric pressure at sea level is 14.696 psi (1,013 millibars or, as measured with a mercury barometer, 29.9213 inches of mercury). At […]

A bold chapter title to be sure but, before going into the fundamental principles of what makes horsepower, let us look at the definition of horsepower. This seems a necessary step because, too often, novice enthusiasts are unaware of how horsepower is defined and derived.   This tech tip is from the full book, DAVID […]