Thermal Barrier Heat Management
Increase Power, Lower Temperatures
The most commonly used TBC is a ceramic-based material that is applied to the top of the piston, the combustion chamber and valve faces in the cylinder head. The TBC holds more heat in the chamber instead of letting it dissipate through the piston, valves and head. This increases cylinder pressure and pushes harder on the piston, producing more power.
The TBC also protects the aluminum piston from the intense heat, so that the air/fuel mixture can be leaned slightly for maximum power without burning through the piston. Since the amount of heat radiated into the rest of the engine is reduced the operating and oil temperatures of the engine come down.
This is also beneficial to the piston rings, improving their radial tension and sealing ability. TBCs are also used on intake and exhaust ports and headers to improve scavenging and lower temperatures, stop corrosion and improve aesthetics.
In addition, TBC moves heat, reducing detonation and increasing the effective oxidation of fuel. When polished it provides a highly reflective surface that further aids in improving flame travel. Unlike the older coatings, TBCs are not subject to cracking and flaking. It actually strengthens the coated part. The cured "Cermet" provides a cap of material that is harder than aluminum and can withstand far greater heat.
During testing, when sufficient heat was applied to melt an untreated piston, the coating did not melt and the soft aluminum piston remained intact.