Understanding the BRZ FA20 Cold Air Intake

Upgrading the intake system on a Subaru BRZ or Scion FR‑S with the FA20 engine is one of the most common first modifications for enthusiasts. The factory intake box is designed for noise suppression and cost efficiency, not maximum performance. A cold air intake (CAI) replaces the restrictive stock assembly with a larger, smoother pipe and a high‑flow air filter, positioned to draw cooler, denser air from outside the engine bay. Cooler air contains more oxygen, which allows the engine to burn fuel more efficiently, resulting in modest but noticeable gains in horsepower and torque — typically 5–15 hp on a naturally aspirated FA20. More importantly, the intake significantly alters the engine’s induction sound, adding a deeper, more aggressive growl as you climb through the rev range. Many kits also eliminate the factory intake resonator (often a plastic chamber designed to mute noise), further sharpening the auditory experience.

Resonator Delete Explained

The term “resonator delete” can refer to two separate modifications on the BRZ/FR‑S/GT86 platform. In the context of the intake system, it means removing the plastic resonator box attached to the intake tube. On the exhaust side, a resonator delete involves cutting out the mid‑pipe resonator and replacing that section with a straight pipe. Both modifications reduce sound deadening and free up a small amount of airflow. For the exhaust, deleting the resonator produces a louder, deeper exhaust note with less drone at highway speeds compared to a full muffler delete. It’s a popular budget‑friendly way to increase exhaust volume without replacing the entire cat‑back system. However, note that removing the exhaust resonator can increase in‑cabin resonance and may push the sound beyond legal noise limits in some jurisdictions. Always check local regulations before proceeding.

Installation Costs Breakdown

Installation costs for a BRZ FA20 cold air intake and resonator delete vary widely based on several factors: the quality and brand of the parts, your geographic location, and whether you choose a DIY approach or professional labor. Below is a detailed cost matrix to help you budget.

Parts Costs

  • Cold Air Intake Kit: Entry‑level brands like K&N or Injen can be found for $200–$350. Mid‑range kits (e.g., Perrin, Grimmspeed) typically cost $350–$450. Premium units from HKS or A’PEXi with carbon fiber tubes or specialized heat shields can reach $500–$700.
  • Exhaust Resonator Delete Pipe: A pre‑fabricated delete pipe (stainless steel, mandrel‑bent) costs $60–$120. If you opt for a custom weld‑in section at a muffler shop, material and labor together run $100–$200.
  • Gaskets & Hardware: For the exhaust delete, you may need new gaskets (approx. $10–$20) and possibly new bolts. Intake kits usually include all necessary hardware.

Labor Costs

  • Cold Air Intake Installation: Professional labor ranges $100–$300. The wide variance depends on shop hourly rates ($80–$150/hour) and whether the shop charges a flat fee. Some shops charge 1–1.5 hours of labor.
  • Exhaust Resonator Delete: If using a pre‑made pipe, a shop may charge 0.5–1 hour ($50–$150). For a custom weld‑in, expect 1–2 hours ($100–$300).
  • Intake Resonator Delete (under hood): This is usually a simple removal (no cutting) and is often included in the intake install. If done separately, a shop might charge $50–$100 for 30 minutes of labor.

Total Estimated Costs

  • DIY (both modifications): Parts only: $260–$820 (depending on intake brand and resonator pipe choice).
  • Professional installation: Parts + labor: typically $400–$1,100.

For example, a budget‑conscious buyer might choose an Injen intake ($280) and a simple resonator delete pipe ($80) for a total parts cost of $360. With professional labor at $200, the total becomes $560. A premium build with a HKS intake ($600), custom weld delete ($150), and labor ($300) would total $1,050.

Time Required for Installation

The actual time needed depends on mechanical skill, tools available, and whether any unforeseen issues arise (e.g., seized bolts). Below are realistic estimates for an experienced DIYer, a novice, and a professional shop.

Cold Air Intake Installation

  • Experienced DIYer: 45 minutes – 1.5 hours. Includes removing the factory intake, installing the new filter and heat shield, securing all clamps, and reconnecting the mass air flow (MAF) sensor.
  • Novice DIYer: 2–3 hours. Time is spent reading instructions, carefully disconnecting wiring harnesses, and double‑checking fitment. Some kits may require minor trimming or relocating of components.
  • Professional Shop: 1–2 hours (including test drive to check for codes). Shops have experience with common pitfalls like overtightening clamps or misrouting hoses.

Exhaust Resonator Delete

  • DIY with pre‑made delete pipe: 1–2 hours using jack stands, a breaker bar, and penetrating oil. Cutting the factory pipe is not required if using a bolt‑on replacement section; if welding is needed, DIY time increases to 3–4 hours for a novice.
  • Professional Shop: 45 minutes – 1.5 hours for a bolt‑on pipe; 1–2 hours for a custom weld‑in. Shops have lifts, welders, and experience dealing with rusted exhaust hardware.
  • Intake resonator delete (standalone): 15–30 minutes. Simply unbolt the plastic resonator from the intake tube and plug any vacuum line if present.

If you plan to do both modifications at home on a weekend, allocate 3–5 hours total for a smooth experience. Rushing often leads to mistakes like forgetting to reconnect the MAF sensor or leaving a loose clamp, which can trigger a check engine light or cause air leaks.

DIY vs. Professional Installation

Choosing between DIY and professional installation involves trade‑offs in cost, time, and risk. Below is a balanced comparison to help you decide.

Advantages of DIY

  • Cost savings: Save $100–$400 in labor.
  • Learning experience: Gain familiarity with your specific vehicle’s components.
  • Flexibility: You can work at your own pace and source exactly the parts you want.

Challenges of DIY

  • Tool investment: You’ll need a socket set, screwdrivers, jack stands (for exhaust work), penetrating oil, and possibly a reciprocating saw or angle grinder for cutting exhaust pipes.
  • Risk of errors: Improper installation can cause vacuum leaks, check engine lights, or even engine damage from unfiltered air entering the combustion chamber.
  • Exhaust work difficulty: Factory exhaust hardware often seizes due to corrosion. Removing the mid‑pipe may require cutting if bolts snap, which adds complexity.

Benefits of Professional Installation

  • Warranty protection: Some shops guarantee their work. If an issue arises, they’ll diagnose and fix it at no extra labor cost.
  • Expertise: Professionals know common pitfalls, such as not overtightening the MAF sensor screws or ensuring proper heat shield clearance to prevent heat soak.
  • Time efficiency: A shop can complete the job in half the time it would take a beginner.

When to Go Pro

  • If you lack basic mechanical skills or the necessary tools.
  • If your vehicle is still under factory warranty and you want to minimize risk of denial for unrelated claims (though CAI and resonator delete are usually considered “non‑affected” modifications, improper install can void specific coverage).
  • If you live in an area with strict noise or emissions testing — a professional can advise on legal compliance.

Additional Considerations

ECU Tuning

While a cold air intake alone does not require an ECU tune on the FA20 engine (the stock ECU can adapt trim to the increased airflow), pairing the intake with a resonator delete and aftermarket exhaust often pushes the system outside the stock calibration’s optimal range. For maximum gains and to prevent a lean condition, consider a custom tune via an ECU flash (e.g., OFT, Ecutek, or COBB Accessport). Tuning can add $300–$600 but unlocks an additional 10–15 hp and smooths out the power delivery. Many tuners offer off‑the‑shelf maps specifically for popular intake and exhaust combinations.

Emissions & Legality

In California and other states that follow CARB regulations, aftermarket intakes must carry an Executive Order (EO) number to be street‑legal. Many popular BRZ intake kits (e.g., A’PEXi, HKS, Perrin) do have CARB EO numbers. Without one, you risk citation at a smog check. Resonator deletes on the exhaust are generally not inspected separately, but drastically increased noise can lead to tickets. Always check your local laws before modifying.

Maintenance Implications

A cold air intake with an oiled cotton gauze filter (like K&N) requires periodic cleaning and re‑oiling every 15,000–30,000 miles. Dry filters (e.g., AEM DryFlow) are easier to maintain but may need replacement. The resonator delete pipe is maintenance‑free, though it can develop rust over time if not made of stainless steel. Regular inspections of intake clamps and exhaust hangers are recommended.

Warranty Risks

Under the Magnuson‑Moss Warranty Act, a dealer must prove that a modification directly caused a failure before voiding a warranty claim. However, if a poorly installed intake causes an engine vacuum leak or the intake tube rubs through a radiator hose, the resulting damage may not be covered. Professional installation with proper documentation reduces this risk.

Conclusion

Installing a cold air intake and performing a resonator delete on your BRZ FA20 is a rewarding upgrade that enhances both sound and performance without breaking the bank. Parts costs range from $260 to over $800, while professional labor adds $150–$400. DIY installation is feasible for those with basic mechanical skills and the right tools, saving labor costs but requiring a careful approach. Professional installation ensures a clean, trouble‑free outcome, particularly for the exhaust resonator delete where cutting and welding may be involved. Before starting, research local emissions laws, consider ECU tuning for maximum benefit, and invest in quality parts from reputable manufacturers. With proper planning, this modification package delivers a more engaging driving experience that stays reliable for daily use or weekend canyon carving.