Practical Engine Airflow. John Baechtel

       Surface Texturing

       Reversion

       Additional Intake Considerations

       Extrude Honing

       Flow Testing Intake Manifolds

      Chapter 5: Cylinder Heads

       Component Compatibility

       Airflow Control Point

       Street versus Race Heads

       Where the Power Comes From

       Best Racing Combo

       Flow Factors

       Valves and Valve Sizes

       Evaluating Cylinder Head Potential

       Piston CFM Demand

       Critical Valve Transitions

       Bore Size

       Port Taper

      Chapter 6: Combustion Chambers

       Cylinder Filling and Pressure Recovery

       Combustion Power and Efficiency

       Chamber Types

       Chamber Flow Concerns

       Chamber Texture

       Valve Shrouding

      Chapter 7: Exhaust System

       Pressure Wave Tuning

       Flow Path Disruptions

       Exhaust Flow Tuning

       Power Adders

       Exhaust Port Surface Texture

       Valve Shape and Angle

      Chapter 8: Flow-Bench Testing

       What Is a Flow Bench?

       Consider Application Differences

       Flow-Bench Information

       Flow-Bench Limitations

       Calculating Lift-to-Diameter Ratios

       Calculating Valve Curtain Area

       Flow-Bench Tools

      Chapter 9: Practical Applications

       Begin with a Software Program

       Air Filters

       Carburetors and Throttle Bodies

       Intake Manifolds

       Cylinder Heads

       The Exhaust Side

      Conclusion

      Source Guide

       DEDICATION

       To Louie Hammel

      My amazing friend Louie Hammel had a fondness for the impossible, frequently offering simple yet profound quips about engine performance that made you stop and think and, more important, imagine. Louie suffered for many years from the debilitating effects of leukemia and has since passed on, but I will always remember the day he looked at me and said, “You know, I’m an engine guy and when I die I want to be cremated and have one of you guys pour my ashes through the carburetor on a screaming high-RPM big-block on the dyno so I can watch all this stuff we talk about first hand.”

      Unfortunately Louie never achieved his goal, but I often wish he had because his reports from the other side would have been awesome and unquestionably accurate. He always wanted a personalized license plate that read TORQUE, and he had a million ideas about ways to generate it and improve engine performance. Although I was busy with a career at Hot Rod and Car Craft magazines, Louie honed his skills testing and developing parts in the dyno rooms at Edelbrock and later became a researcher and dyno technician at McFarland, Inc., evaluating and developing high-performance components for Jim McFarland.

      Later, after Louie became sick, he used to come by my dyno shop in the afternoons and weekends and we would bench race engine tech and theory endlessly. Whenever something stumped us, we immediately thought to “ask Louie,” whereupon he addressed our question with the thoughtful power of his amazing intellect. That made some people jealous, but he only sought to offer well-thought-out opinions, and he usually had a perfectly good explanation that solved our problem.

      Louie was no poser. He never cared if he impressed anyone or what others thought of his ideas. He thought well beyond that and was truly immersed in the magic of engine performance and, in particular, the science of engine airflow. If I’ve learned anything over all these years, much of it came from Louie’s remarkably thoughtful questions and subsequent discourse on said matters. Many of us miss Louie even to this day and can’t forget the remarkable impression he left on us. And thus I dedicate this book to him, an exceptionally observant and knowledgeable man.

      Somehow I think he still may have managed to find his way inside a running engine and he is still in there, taking notes and preparing reports for his old friends who still feel the need to “ask Louie.” R.I.P., buddy.

       This photo was shot at Jim McFarland’s think tank R&D shop in Torrance, California, in the early 1990s before Louie was diagnosed with leukemia. That’s an early GM ZZZ engine on the dyno. Left to right: Kevin McClelland, Rod Sokoloski, Louie Hammel, Keith Rudolph, and Jim McFarland.

       ACKNOWLEDGMENTS

      Resources are the lifeblood of any tech book. Without them an author could never pull together all the relevant information that applies to the subject of the book. Very few authors can write this stuff off the top of their head. It takes a concerted effort and the unfailing cooperation of numerous people who also have lives, jobs, and other things to do. Sometimes they forget or take longer than expected, but they come through in the end and their contributions lend substance to the book. Many people contributed to this book by necessity as I am far from an expert on the nuances of engine airflow. Each of them has my profound gratitude for the effort they expended.

      Patrick Hale was my chief supporter and sounding board and, as I requested of him and everyone else, he pulled no punches when pointing out errors and inaccuracies. At the same time he contributed valuable input and commentary that was helpful beyond measure. The same can be said for Darin Morgan at Reher-Morrison Racing Engines whose intimate knowledge of internal engine passages seems virtually endless. Nick Smithberg at Smithberg Racing provided a wealth of photographic support, knowledgeable content, and the basis for a new and valuable relationship. Jack Kane at EPI, Inc. came through at the last minute with important artwork as did Dave Secunda at Wilson Manifolds, Jeff from Rottler Manufacturing, and Byron Wright at Thorpe Development. Mike Lefevers of Mitech Racing Engines contributed numerous photos and John Kyros of the GM Media Archives came through once again with critical historical photos.

      I learned important philosophies from acknowledged experts such as Kenny Duttweiler, Jim McFarland, Larry Meaux, Chuck Jenckes, and many others. My admiration and heartfelt thanks to all of them.

      Engine airflow is a complex subject. My intent is to provide a solid foundation of airflow characteristics that everyone can work from to advance their own projects. The fundamentals are pretty much set in stone, but their consistent application is crucial to making big power.