BMW S14 Piston Set Our piston packages are highly developed to provide you with maximum performance and reliability. All of our pistons are designed utilizing advanced 3D modeling software   and are stringently tested by finite element analysis. These piston packages include   several features engineered into them to provide you with performance and reliability.   Contact reduction grooves that are designed to disrupt detonation waves. Accumulator   grooves that collect residual gasses during combustion and alleviate top ring flutter while   increasing ring seal. Constant pressure grooves that equalize pressure to the back of the   top ring groove. Radius domes that are developed to maximize quench and to eliminate   the possibility of hot spots which promote detonation. Additional Options:   Dome Coating   Skirt Coating   Upgraded Pins   Upgraded Stainless Steel Rings Price: $814.00