Tomei Race Spec +1mm Valve Set (04+ STI, 02-14 WRX)

  • Ocersized Valves - +1mm
  • Waisted Stem
  • Engine Specific Design
  • Heat Resistance & Durability
  • Intake Valves material: SUH35 Steel
  • Exhaust Valves material: Inconel 751
  • Standard Size Intake - 37mm / Exhaust - 33mm
  • Sold as Complete Set Intake & Valves


TOMEI was then recognized for its technology, performance and reliability that we had cultivated into our own design products and had a large support base from motor sports end users and tuners. Then the “TOMEI” brand was born through experience.

Pour the power technology in the race experience in product development in pursuit of low cost and high quality in basis to provide the name of the product called technology ….

We achieve this mission, is willing to work hard in the future to meet the expectations of motor sports enthusiasts.

The oversized head diameter is designed specifically for each application, significantly improving the flow rate.


The waisted stem allows a greater volume of air/gases to enter and exit the combustion chamber as the valve extends. (not available on some models)

Each valve is designed and precision machined specifically for the intended engine/application.The head, face, stem and lock groove designs have also been optimized to enhance sealing performance, efficiency and durability.

Intake: The intake valves are made using SUH35 HEAT RESISTANT STEEL which is more commonly used to make exhaust valves. These are then coated with a special formula that further improves the valves' resistance to heat, wear and corrosion.
Exhaust: In order to withstand temperatures of up to around 1000℃, the exhaust valves are made using a nickel based heat resistant alloy, INCONEL 751.

  • +1mm Size / Intake - 37mm / Exhaust - 33mm

Vehcile Fitment:

  • 2004+ STI
  • 2002-2014 WRX

warning_symbolWARNING: Operating, servicing and maintaining a passenger vehicle or off-road vehicle can expose you to chemicals including engine exhaust, carbon monoxide, phthalates, and lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. To minimize exposure, avoid breathing exhaust, do not idle the engine except as necessary, service your vehicle in a well-ventilated area and wear gloves or wash your hands frequently when servicing your vehicle. For more information go to

More Information
Product Type Engine
Engine Cylinders and Valvetrain
Brand Tomei
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