Practical Engine Airflow. John Baechtel

      

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      © 2015 by John Baechtel

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      Layout by Monica Seiberlich

      ISBN 978-1-61325-157-7

      Item No. SA308

      Library of Congress Cataloging-in-Publication Data Available

      Written, edited, and designed in the U.S.A.

      10 9 8 7 6 5 4 3 2 1

       Title Page:

       A similar choke point exists on the exhaust side. It also represents the minimum cross section and typically has a larger radius to encourage smooth exhaust flow, which exits under high pressure.

       Back Cover Photos

       Top Left:

       The throat area immediately above the valveseat is the controlling factor in airflow efficiency. Maximum velocity across the valve should be generated here.

       Top Right:

       Cylinder heads are the most influential component of an internal combustion engine. They are the gatekeeper that regulates the amount and quality of the air/fuel mixture entering the engine.

       Bottom Left:

       Naturally aspirated applications typically require much more flow-bench work to extract maximum performance for each application. Experience pays off, but it still may require long hours of trial and error. (Photo Courtesy Smithberg Racing)

       Bottom Right:

       Modifying port entry angles via specific port matching produces power. The match between the runner exit and the intake port entry should be almost seamless with no sharp edges or area change. Epoxy filling is sometimes required to accomplish the smooth finish. (Photo Courtesy Wilson Manifolds)

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      CONTENTS

Dedication

Acknowledgments

Introduction

Chapter 1: Airflow Basics

Airflow Path

The Seven Cycles to Max Power

Torque and Horsepower

Volumetric Efficiency

Theoretical CFM

Understanding BSFC

Contributing Engine Systems

Chapter 2: Relevant Properties of Air

Physical Composition of Air

Mass and Weight

Density

Coping with Variables

The Ideal Gas Laws

Correction Factors

The MSA and the Air Density Index

Density Altitude

       Fuel Properties to Consider

       Octane Rating

       Gasoline Variables

       Conclusion

      Chapter 3: Engine Airflow Components

       Fundamentals of Air Motion

       Cross Sections and Path Lengths

       Carburetors and Throttle Bodies

       Air Velocity and Boundary Layers

       Obstructions and Pressure Changes

       Wave Tuning

       Torque Peak RPM

      Chapter 4: Intake Manifold

       Intake Manifold Types

       Plenum Characteristics