10 Things You Always Wanted to Know About Engines

This article is copied from the September 1999 issue of Hot Rod Magazine

By Ray T. Bohacz

     The performance industry is now recognizing what the military has known for years: Chemically treated surfaces can make engines run better.  The first use of coatings was on exhaust headers, which increased power by limiting the thermal transfer from the pipes to the area under the hood.  By insulating the headers and retaining the heat, the laws of physics dictate that you will increase exhaust velocity.  Conversely, when heat is allowed to dissipate, the exhaust velocity will decrease.  Lower underhood temps tend to increase VE.  Some racers are realizing the benefits of applying a coating to the tops pf the pistons as well as the cylinder heads.  By limiting thermal transfer into the piston and heads, there is more energy available to push against the piston, which will then create more force to turn the crankshaft.  It all comes back to flame speed and thermodynamics.  Thermal barrier coatings increase flame speeds when applied to piston tops due to their reflectability and retained heat.  This allows cylinder pressures to peak sooner, and the quicker burn rate requires less timing and reduces the possibility of abnormal combustion.