John Baechtel - Performance Automotive Engine Math

Books like this rarely happen in a vacuum. This one is the result of 40 years of practical application and the good fortune of lengthy association with brilliant individuals whose willingness to share their knowledge is surpassed only by their passion for engines. Most of the contributors hold advanced degrees and have excelled in their respective fields. Most of the formulas herein are widely known. A few are recalled from a discussion of automotive math formulas compiled by Larry Atherton in the mid 1990s while working on the original version of Motion Softwares DeskTop Dyno software, and I have seen them elsewhere from time to time. Larry polled automotive engineers deep within the bowels of GM and Ford engine labs and, while most of what he learned is beyond the scope of this book, it contributed greatly to my further understanding of the complicated details of internal combustion engines and it is still available in Motion Softwares extensive online manuals for DeskTop Dyno and Dynomation. Among the many formulas I recall learning from Athertons early investigations is one for the instantaneous acceleration of the piston from TDC, which I had seen nowhere else until it was published in Forbes Airds excellent Automotive Math Handbook.

A little-known formula for calculating torque peak location and exhaust header primary tube size was contributed by my mentor extraordinaire and perhaps the most widely respected authority in our industry, Jim McFarland. Jim also afforded me the honor of checking my work for mathematical errors and penning the Foreword for the book. I should also acknowledge John Lawlor, whose groundbreaking Auto Math Handbook has improved the knowledge of countless engine enthusiasts for decades. Another significant contributor is Jeff Smith from Car Craft magazine, a valued colleague whose 30-year friendship has contributed enormously to my ever-expanding automotive database, and who generously consented to giving the manuscript a read for accuracy. Thanks also to Sigrid Michelsen and my best friend Larry Beatson for their contributions to the initial research for the book. They helped immensely with supporting details such as the origins of pi, conversion specs, and the history of complicated mathematical equations.

Many thanks also to my daughter Tamara, a graphic artist and web designer, who helped immensely with various layout issues during production of the book. Her tireless efforts helped ensure the look of the final product, and helped bring it in on time. And, of course, thanks and acknowledgements to my old Bonneville racing partner, Chuck Jenckes, a NASCAR and Formula 1 engineer and endless source of performance engine knowledge.

Finally, my unending thanks to Publisher Dave Arnold, whose patience and generosity remain unsurpassed. Likewise to Scott Parkhurst, who had my back throughout the process, shot many of the photos, and whose ability to edit a pile of gibberish into a cohesive and useful package never ceases to amaze me.

John Baechtel

John Baechtel is a former editor of Car Craft and Hot Rod magazines and was the founding partner of the Westech Performance Group engine dyno testing facility. He is also a member of the Bonneville 200 MPH club, holding both SCTA and FIA International speed records. He drove the first production-based Mustang Cobra past the 200-mph mark in 1993 and was the driving force behind the restoration of the Summers Brothers Land Speed Record car for The Henry Ford museum. With more than 35 years of high-performance engine and vehicle testing under his belt, he is still passionate about engines and high-performance technology. He currently serves as a technical consultant to several performance aftermarket companies while pursuing his interest in land speed racing and grooming his extensive collection of land speed record model cars and memorabilia