For those in the know, the annual Advanced Engine Technology Conference (AETC) is a tremendous resource for sharing information, opening the lines of communication, and making valuable connections within the industry. In years past, there have been many, many topics--but in its 19th year the masterminds behind the AETC decided, in their infinite wisdom, that 2008 was the perfect time to address LSx performance. Days away, the Performance Race Industry (PRI) show was about to reveal some of the most exciting new products for the Gen III and IV engine family, so what better time for a conference on the subject? GM High-Tech Performance was lucky enough to get its name on this fantastic event as one of the presenting magazines, and soak up all of the juicy nuggets of wisdom that the industry's best and brightest could doll out in a series of presentations. Follow along to learn everything you can about the history of the LS platform, machining and building big cube motors, valvetrain design, building reliable big boost combinations for max power, intake manifold design, and much more.
Dr. Dean Hill, New Mexico State University
"A Theoretical Understanding of the Otto Cycle and Thermodynamic Optimization for LSX Engines"
Dr. Dean Hill, who holds a Ph.D. in Chemistry from Michigan State, started off the conference with a general discussion of the operation of the 4-cycle internal combustion engine that we know and love, thus giving a basis to get everyone in attendance on roughly the same page. Hill's treatment of the topic is somewhat unorthodox in that he breaks down the Otto cycle into not four, but six, distinct phases, which include the traditional intake, compression, power, and exhaust strokes, along with two more mixed in: combustion (occurring between the compression and power strokes, during which the piston is roughly stationary at TDC as the air/fuel mix is ignited and burns); and finally, an unnamed additional phase that occurs between the power and exhaust strokes, when the exhaust valve opens against residual pressure with the piston at BDC. These additional two phases, he explains, are critical to look at for our purposes.
Through his presentation of Pressure-Volume diagrams, calculations for important values such as Volumetric Efficiency and the Work of Compression, and even chemical formulas for the combustion of gasoline, Dr. Dean (as he is known) shows how power output of an engine can be calculated mathematically, and that the calculations can be quite accurate if done meticulously. He proves the point where he comes within 7 horsepower of an engine's ultimate 522hp dyno reading--"not bad for comparing cycles to cycles!" Overall, Dr. Dean provided an informative discussion that demonstrated the importance and utility of applying science and mathematics to engine design.