For Subaru EJ20 | EJ25 | WRX | STi | SUPERTECH Exhaust Valve Stem Seal

We apply more than 30 years of experience in the development of each and every Supertech racing valve we sell. Combine this experience with state of the art equipment such as ultrasonic tests, x-rays, laser measurement equipment, and applications like computerized Finite Element Analysis (FEA) and it is no wonder why supertech has some of the best performance products on the market.

While this is more than most manufacturers we dont stop there. We also do extensive testing working very closely with many of todays top engine builders in order to continuously improve our products. All of this is meant to insure Supertechs industry leading reputation for high flow rates, durability and uncompromising quality.

Production of our racing valves begins with a one piece forging, where the head of the valve is forged under a slow two step process to keep a good material grain flow. The forging is then CNC machined in several steps to ensure the precision of the final dimensions. We then do another heat treatment for stress relieving followed by a nitride hardening treatment (or coating process depending on the application). Lastly, we do one more grinding, followed by our patented Superfinishing of the surface to ensure that each valve is free of any imperfections and the dimensions are precise.