GrimmSpeed Phenolic Thermal Spacer 3mm 2002-2014 WRX / 2004-2021 STI / 2005-2009 Legacy GT / 2004-2013 Forester XT / 2005-2009 Outback XT

Keep your intake air cool and boost horsepower with GrimmSpeed’s Phenolic Intake Manifold/TGV Thermal Spacer. By raising the intake manifold off the hot aluminum engine, these spacers significantly reduce heat soak, delivering denser air for improved efficiency and power.

Why Phenolic Spacers?

• Reduces heat transfer from engine to intake manifold
• True phenolic material, not lower-quality alternatives
• Cooler air = denser air, increasing power (~1% per 5°F reduction)
• Direct bolt-on, works with factory gaskets or GrimmSpeed gaskets
• USA-made and safe for use with race fuel, E85, or methanol

Performance:

• OEM intake manifold temp: 152°F
• With 3mm Phenolic Spacer: 134°F
• With 8mm Phenolic Spacer: 108°F (over 44°F reduction!)

Phenolic spacers conduct 300–900x less heat than OEM steel gaskets, keeping intake air cooler and engine power optimized.