What it does:

• Greatly reduces the transfer of heat from engine to intake manifold thus reducing heat soak.
• One of a kind true Phenolic material, not cutting board material like others.
• The cooler your intake temperature is the denser the air is which leads to more power
• For every 5 degree reduction in air temperature, increases power by 1%.
• The cooler and denser the intake air that the engine sucks in, increases the amount of air that can be mixed with fuel thus increasing efficiency.
• Direct bolt-on.
• When running the oem gasket only, your intake manifold gets very hot to the touch, enough to burn your hand. When the oem gasket is replaced with our Phenolic Spacer, your hand can be placed on the intake manifold without any issues.
• We have installed both with and without OEM Subaru Gaskets and have had no issues with either way. We do recommend using 2 sets of oem gaskets however, one on both sides of the spacer.
• USA made

How it works:

• The intake air in your engine travels through the airbox into the turbo, then into the aluminum intake manifold. The air exits the intake manifold and goes directly into the engine.
• While the intake air is within the intake manifold it picks up alot of heat from the aluminum intake manifold. This added heat reduces air density thus reducing engine power capabilities.
• In stock form your engine has a steel gasket between the intake manifold and engine which allows the heat from the engine to quickly transfer into the intake manifold. By replacing this steel gasket with the GrimmSpeed™ Phenolic Spacer you are greatly reducing the transfer of engine heat into the intake manifold.
• Phenolic Spacers are able to withstand 500+ degrees F. Subaru engines run at the hotter end of operation around 200 degrees F, so the Phenolic Spacer is well within its max running temperature. GrimmSpeed™ has tested that it is also safe to run race fuel, E85, and methanol with the Phenolic Spacers.
• The Phenolic Spacer will conduct 300-900 times less heat than the oem steel gasket.

Temperature Testing Data: Testing at 1/2 hour intervals. All testing was conducted fairly in Fahrenheit measurements on ONE day at a consistent outside temperature.

Test #1 - OEM measurement from IM without spacers, 152 degrees.

Test #2 - with 3mm phenolic spacers the temp dropped to 134 Degrees

Test #3 - With 8mm phenolic spacers the temp dropped to an outstanding 108 Degrees!!!

That is an OVER 44 Degree drop with the largest phenolic spacers!