02-07 WRX / 04-21 STI GrimmSpeed Air Oil Separator
02-07 WRX / 04-21 STI GrimmSpeed Air Oil Separator
GrimmSpeed
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PRODUCT DETAILS
RallySport Direct proudly carries a great selection of quality aftermarket performance products brought to you by GrimmSpeed.
This is the GrimmSpeed Air Oil Separator.
If you're familiar with modifying your vehicle, then you will know the importance of an air/oil separator, especially in a boxer-designed engine. The GrimmSpeed example comes with a unique design as it utilizes the factory oil filler cap location to maintain your PCV system while separating the harmful oil and vapors from the crankcase, as well as the head ventilation system. This will prevent oil from coating the intake manifold which will make can make its way onto the valves which will affect the octane rating which leads to detonation issues and performance issues.
DETAILS:
- Anodized black finish option with white GrimmSpeed logo
- The unique design utilizes the factory oil filler cap location to maintain your PCV system
- Prevents harmful oil and oil vapors from entering the crankcase and head ventilation system
- Prevents the reduction of fuel octane
- Prevents the higher chances of engine knock and detonation
- Prevents worse emissions
- Prevents higher oil consumption
- Very compact design
- Coalesces oil without using a mesh media which can cause contaminants to collect and cause a sludge buildup
- The design eliminates the need to check/empty your catch can while refilling your oil
- Includes all of the required fittings
- Includes hose that is cut to specific lengths and zip ties
WHY WE CARRY THIS
We only list parts we’d run ourselves or recommend to a friend building a real car. If it feels vague, unverified, or inconsistent, it doesn’t make the cut.
- Fitment-first mindset — no “universal” roulette
- Brand reputation matters — we favor proven manufacturing
- Support that actually responds with real answers
WHAT TO EXPECT
This is the clean path: correct fitment, clean install, and results that match the intent.
- Install-ready experience with correct mounting where provided
- Finish that holds up to real driving, not just photos
- Selections on this page drive the exact fitment shipped
TRUST, BUILT INTO THE PROCESS.
Anyone can list parts. We curate what belongs on a serious build. Our goal is simple: fewer surprises, cleaner installs, and confidence when you hit “Buy.”
Fitment checked
We prioritize vehicle-specific listings and clear selection logic so you’re not gambling on compatibility.
Brand discipline
Proven manufacturing and consistent quality matter more than hype. We bias toward what actually holds up.
Real support
If you have a question, you’ll get a human answer that helps you finish the build — not a copy-paste shrug.
RallySport Direct proudly carries a great selection of quality aftermarket performance products brought to you by GrimmSpeed.
This is the GrimmSpeed Air Oil Separator.
If you're familiar with modifying your vehicle, then you will know the importance of an air/oil separator, especially in a boxer-designed engine. The GrimmSpeed example comes with a unique design as it utilizes the factory oil filler cap location to maintain your PCV system while separating the harmful oil and vapors from the crankcase, as well as the head ventilation system. This will prevent oil from coating the intake manifold which will make can make its way onto the valves which will affect the octane rating which leads to detonation issues and performance issues.
DETAILS:
- Anodized black finish option with white GrimmSpeed logo
- The unique design utilizes the factory oil filler cap location to maintain your PCV system
- Prevents harmful oil and oil vapors from entering the crankcase and head ventilation system
- Prevents the reduction of fuel octane
- Prevents the higher chances of engine knock and detonation
- Prevents worse emissions
- Prevents higher oil consumption
- Very compact design
- Coalesces oil without using a mesh media which can cause contaminants to collect and cause a sludge buildup
- The design eliminates the need to check/empty your catch can while refilling your oil
- Includes all of the required fittings
- Includes hose that is cut to specific lengths and zip ties
