Intake Manifold Phenolic Spacer - 3mm

• 2004–2013 Subaru | Forester XT
• 2002–2014 Subaru | WRX
• 2004–2021 Subaru | WRX STI
• 2005-2009 Subaru | Legacy GT

GrimmSpeed Intake Manifold Phenolic Spacer - 3mm (018001)

Per GrimmSpeed, your intake manifold sits on a superheated boxer engine, and the cooler your intake air is, the more power your car can make. GrimmSpeed's answer is to raise the intake manifold off the engine with its Phenolic Intake Manifold/TGV to Engine Thermal Spacer. Phenolic spacers have been used for years by many other specialized automotive companies, but GrimmSpeed describes this as new technology to the Subaru world.

What phenolic spacers do (per GrimmSpeed)

• Greatly reduce the transfer of heat from the engine to the intake manifold, reducing heat soak
• One-of-a-kind true phenolic material
• Cooler intake air is denser air, which leads to more power; GrimmSpeed states that every 5 degree reduction in air temperature increases power by 1%
• Cooler, denser intake air increases the amount of air that can be mixed with fuel, increasing efficiency
• Direct bolt-on
• USA made

Per GrimmSpeed, when running a gasket only, the intake manifold gets hot enough to the touch to burn your hand; with GrimmSpeed gaskets paired with the Phenolic Spacers, your hand can be placed on the intake manifold without issues. GrimmSpeed recommends using 2 sets of its gaskets, one on each side of the spacers.

How they work (per GrimmSpeed)

Intake air travels through the airbox into the turbo, then into the aluminum intake manifold and directly into the engine. While in the intake manifold, the air picks up heat from the aluminum manifold, which reduces air density and engine power. In stock form, a steel gasket between the intake manifold and engine lets engine heat transfer quickly into the manifold. Replacing that steel gasket with the GrimmSpeed Phenolic Spacer and gaskets greatly reduces the transfer of engine heat into the intake manifold.

Per GrimmSpeed, the Phenolic Spacers withstand 500+ degrees F, well above the roughly 200 degrees F that Subaru engines run at, and conduct 300-900 times less heat than the OEM steel gasket. GrimmSpeed has also tested them as safe to run with race fuel, E85 and methanol.

Testing (per GrimmSpeed)

GrimmSpeed tested at 1/2 hour intervals, with all measurements in Fahrenheit taken on one day at a consistent outside temperature.

• OEM, measured from the intake manifold without spacers: 152 degrees
• With 3mm phenolic spacers (this part): the temperature dropped to 134 degrees
• For comparison, GrimmSpeed's test of its 8mm phenolic spacer dropped to 108 degrees, which GrimmSpeed describes as an over 44 degree drop with its largest spacer

Fitment (per GrimmSpeed)

• 2002-2014 Subaru WRX
• 2004-2021 Subaru STI
• 2004-2013 Subaru Forester XT
• 2005-2009 Subaru Legacy GT
• 2005-2009 Subaru Outback XT

Q: Which vehicles does it fit?
A: GrimmSpeed lists the 2002-14 WRX, 2004-21 STI, 2004-13 Forester XT, 2005-09 Legacy GT and 2005-09 Outback XT.

Q: Do I need gaskets?
A: GrimmSpeed recommends using 2 sets of its gaskets, one on each side of the spacers.

Q: How hot can the spacer get?
A: GrimmSpeed rates the Phenolic Spacers to withstand 500+ degrees F.

Q: Is it safe with E85?
A: GrimmSpeed has tested it as safe to run with race fuel, E85 and methanol.

Q: What did GrimmSpeed measure with the 3mm spacer?
A: In GrimmSpeed's test the intake manifold dropped from 152 degrees (OEM) to 134 degrees.

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