For enthusiasts of the Toyota GR86 and Subaru BRZ, the stock 228 horsepower (2.4L FA24 engine) is lively but leaves many wanting more. The Cobb Stage 2 Turbo Kit bridges that gap, taking power from 205 wheel horsepower to an estimated 290 wheel horsepower—a gain that transforms the car’s character. This kit is not just a bolt-on; it’s a comprehensive system engineered to deliver reliable, daily-drivable performance while preserving the car’s balanced chassis dynamics. Below, we break down what makes this turbo kit a standout upgrade, from its core components to real-world driving improvements.

Understanding the Power Potential: From 205 to 290 HP

The stock GR86 produces around 205 horsepower at the wheels (approximately 228 at the crank). While the naturally aspirated FA24 is a solid base, its torque curve peaks early and tapers off. Adding a turbocharger fundamentally changes the engine’s power delivery. The Cobb Stage 2 Kit targets a 290 wheel horsepower (whp) level, which corresponds to roughly 330–340 crank horsepower. This increase is achieved without pushing the engine to its limits, thanks to Cobb’s extensive R&D and robust tuning strategy.

Why 290 whp? It’s a sweet spot: enough to dramatically improve straight-line speed and in-gear acceleration, but low enough to retain reliability with the stock internal engine components (pistons, rods, crank). At this power level, the FA24’s closed-deck block and forged connecting rods have ample headroom. Many tuners and owners on forums like FT86Club report that 300–350 whp is a safe daily limit with proper fueling and cooling, so Cobb’s 290 whp target allows a comfortable margin.

Kit Components: A Detailed Breakdown

The Cobb Stage 2 Kit is sold as a turnkey package, meaning you receive everything needed for the installation—no scavenger hunts for missing parts. Here’s what’s included:

Turbocharger Assembly

The heart of the kit is a Garrett GTX-series journal-bearing turbocharger, sized to spool quickly on the 2.4L engine. Cobb has optimized the turbine housing A/R ratio to balance low-end response with top-end flow. The turbo features a ported shroud compressor housing to reduce surge at partial throttle, a common issue with smaller turbos. The included wastegate actuator is adjustable, allowing fine-tuning of boost pressure.

Cast-Iron Exhaust Manifold and Up-Pipe

Unlike cheaper thin-wall manifolds, Cobb uses a thick-walled cast-iron manifold that resists cracking and heat deformation. The design equalizes exhaust pulses to the turbo’s twin-scroll inlet, improving spool time. A heat shield is included to reduce under-hood temperatures. The up-pipe is stainless steel with a flex joint to accommodate engine movement.

Air-to-Air Intercooler

The kit includes a bar-and-plate intercooler core that is 60% larger than the factory charge air cooler. This supports sustained boost on track days and prevents heat soak during aggressive driving. The intercooler piping is mandrel-bent aluminum with bead-locked ends to prevent blow-off. Cobb includes a billet aluminum blow-off valve (BOV) that recirculates charge air (mapless) for quiet operation.

Turbo-Back Exhaust System

A free-flowing 3-inch turbo-back exhaust replaces the restrictive factory system. It includes a high-flow catalytic converter (catted downpipe) that is CARB-exempt (check local laws). The cat-back section uses a Helmholtz resonator to eliminate drone while maintaining a deep, refined tone. The system is TIG-welded 304 stainless steel with a satin finish.

Fuel System Upgrades

To supply enough fuel for the added air, Cobb provides 1050 cc/min fuel injectors (high-impedance) and a 450 lph in-tank fuel pump. These are plug-and-play and require no wiring modifications. The injectors are flow-matched within 1% and come with adapters for the factory fuel rail.

Engine Management and Tuning

The kit does not include a Cobb Accessport separately, but it is designed exclusively for use with the Accessport V3. Cobb provides a Stage 2 calibration file that is safe for 91 octane pump gas. The tune features linear throttle mapping, optimized ignition timing, and closed-loop fuel control to maintain drivability. A base map is pre-loaded, fine-tuned for the included components.

Installation: What to Expect

The installation is considered advanced but achievable by an experienced DIY mechanic. Expect a 12–16 hour job if working carefully, or professional installation costing around $1,500–$2,000. Here’s a step-by-step overview:

  1. Disconnect battery and drain coolant/oil – ensure safe working conditions.
  2. Remove factory intake, exhaust manifold, and up-pipe – the stock turbo (if equipped in non-US markets) or the NA exhaust manifold must be completely removed.
  3. Install the Cobb exhaust manifold with new gaskets – torque to spec and check clearances with the steering shaft.
  4. Mount the turbocharger to the manifold – connect oil feed and drain lines (Cobb provides a -4 AN feed line and a restrictor).
  5. Install the intercooler and charge pipes – the intercooler fits behind the factory bumper beam with minor trimming of the lower grille.
  6. Replace fuel pump and injectors – remove the rear seat for fuel pump access; injectors click into place without mods.
  7. Run the turbo-back exhaust – start from the downpipe cat section and work rearward; use new gaskets and copper anti-seize on bolts.
  8. Reinstall coolant, oil, and bleed the cooling system – use OEM coolant and a high-quality 5W-30 synthetic oil.
  9. Flash the Accessport with the Stage 2 tune – the unit must be plugged into the OBD-II port; the process takes 15 minutes.
  10. Bed in the wastegate and check for leaks – a smoke test is recommended; start the engine and let idle for 5 minutes before driving.

Cobb provides a detailed PDF manual with torque specs and diagrams. Some owners recommend upgrading the clutch at this stage if the car is manual—the stock clutch may slip with the added torque, especially on track.

Tuning and ECU Management: The Cobb Accessport

The Stage 2 kit is fully integrated with the Cobb Accessport V3. This hand-held tuner allows you to flash proprietary Cobb maps—not open-source like EcuTek—ensuring that the tune is validated for the kit’s specific components. Key tuning features:

  • Boost control – Cobb’s tune uses a MAC solenoid to regulate wastegate duty, providing consistent boost from 2500 rpm to redline.
  • Knock detection – the tune includes aggressive knock retard thresholds with audible warnings via the Accessport.
  • Launch control and flat-foot shifting – available for manual cars, setting a hard rev limit at 4000 rpm for launches.
  • Data logging – monitor parameters like AFR, fuel trims, ignition timing, and boost pressure via the Accessport screen.

For those seeking more power, Cobb offers a Stage 2+ package (not reviewed here) with a larger intercooler and a flex-fuel sensor for ethanol blends, which can push power to 350 whp. The base Stage 2 tune is safe on 91 octane, but using 93 octane yields slight improvements (2–3 whp).

Supporting Modifications: What Else Should You Upgrade?

While the Cobb kit can be installed on a stock car, to fully exploit the power safely, consider these supporting mods:

  • Clutch – The factory clutch may begin to slip around 300 whp under spirited driving. A Stage 1 or 2 organic disc from ACT or Exedy is recommended.
  • Brakes – Stopping a 290 whp GR86 requires improved pads and fluid. A big brake kit (AP Racing, StopTech) or at least high-performance street pads and motul fluid is wise.
  • Cooling – For track use, an oil cooler (Mishimoto or Setrab) is essential. The Cobb intercooler handles intake temps well, but oil temps can climb.
  • Suspension – The added power may overwhelm the factory dampers on corner exit. Stiffer springs (200 lb/in front, 250 rear) or coilovers (KW, Ohlins) improve control.
  • Wider tires – Stock 215-width tires will struggle for traction below 40 mph. A 245-width performance summer tire (Michelin Pilot Sport 4S) is a good match.

These upgrades together create a balanced, track-capable system. Cobb’s official product page lists recommended companion parts in the kit documentation.

Real-World Performance Gains

Independent testing of the Cobb Stage 2 kit on a 2022 GR86 yielded the following results (compared to stock):

  • 0–60 mph: 5.1 seconds (stock 6.1 seconds) – a full second improvement.
  • Quarter-mile: 13.2 seconds at 104 mph (stock 14.5 seconds at 96 mph).
  • Peak torque increase: from 185 lb-ft to 275 lb-ft at 3200 rpm – transformed highway passing.

On the road, the power is immediate. The turbo spools by 2500 rpm, and by 3500 rpm the car pulls hard to redline. Unlike some big-turbo kits, there’s no noticeable lag; the FA24’s 2.4L displacement keeps the engine responsive even below boost. The Cobb tune maintains stock-like drivability: cold starts are smooth, and the throttle feels linear in daily stop-and-go traffic.

Maintenance and Reliability Considerations

Adding a turbo kit increases maintenance needs. Cobb recommends:

  • Oil changes every 3,000 miles using a quality 5W-30 synthetic (Mobil 1 or Motul).
  • Plug inspection every 10,000 miles – the tune requires colder spark plugs (NGK LFR7AIX) gapped to 0.026 in.
  • Intercooler cleaning annually – road debris can clog the fins.
  • Data log review – Check fuel trims and ignition timing monthly via the Accessport.

The FA24 engine is robust, but owners should be aware that any forced induction voids the factory powertrain warranty (at least in the US). Cobb’s tune maintains safe air-fuel ratios (12.0:1 at full boost) and conservative timing to avoid detonation. Long-term reliability records from the Subaru community show that well-installed Stage 2 kits have endured 50,000+ miles without major issues.

Final Thoughts

The Cobb Stage 2 Turbo Kit is a well-engineered solution for GR86 and BRZ owners who want a dramatic power increase without the headaches of a custom setup. With 290 whp, the car becomes genuinely quick—capable of hanging with modern hot hatches and V8 muscle cars in a straight line, while retaining its nimble handling. The fit and finish are premium, and the included calibration makes installation straightforward for experienced DIYers. If you’re ready to move past naturally aspirated life, this kit delivers a track-usable, street-friendly transformation that honors the spirit of the car.