The FA20DIT Paradigm: Why the 2015 WRX is Different
When Subaru introduced the VA-chassis WRX in 2015, it marked a monumental shift in the brand's performance lineage. The legendary EJ255 was retired, replaced by the direct-injected FA20DIT engine, and the drivetrain was updated to a revised 6-speed manual transmission (the TY856 series). For enthusiasts and technicians tackling a 2015 WRX clutch replacement, this generational leap introduced a critical mechanical distinction that catches many off guard: the 2015+ WRX utilizes a push-type clutch release mechanism, whereas the STI retained the older pull-type setup.
Ordering an STI clutch kit for a 2015 WRX will result in immediate fitment failure and potential damage to the transmission fork. Furthermore, the FA20DIT's aggressive low-end torque curve places unique stresses on the factory dual-mass flywheel (DMF). Whether you are replacing a slipping OEM clutch or upgrading for a Stage 2 tune, selecting the correct components is paramount. This step-by-step guide will walk you through the exact kit selection, flywheel dilemmas, and factory torque specifications required to execute a flawless clutch swap on the 2015-2021 WRX platform.
Step 1: Define Your Power Level and Traction Requirements
Before browsing catalogs, you must objectively evaluate your FA20DIT's current and future power output. The WRX's all-wheel-drive system puts immense shock-load on the clutch disc during hard launches, meaning your torque capacity requirement is higher than that of a RWD vehicle with similar horsepower.
Stock to Stage 1 (Under 300 WHP)
If your WRX is completely stock or running a basic Stage 1 ECU calibration (typically 280-295 WHP), an OEM replacement or a high-quality organic Stage 1 kit is ideal. These kits maintain the smooth, progressive engagement of the factory pedal feel while offering a slight bump in clamping force. They are perfect for daily driving and occasional canyon carving.
Stage 2 and Built FA20s (300 - 450 WHP)
Once you add a downpipe, front-mount intercooler, and a Stage 2 tune (pushing 310-340 WHP), the factory clutch will rapidly succumb to slip in higher gears. At this level, you need a Heavy Duty (HD) pressure plate paired with a Cerametallic or Kevlar disc. Be warned: these setups introduce noticeable chatter at low speeds and require a more deliberate pedal technique.
Step 2: Solving the Dual-Mass Flywheel (DMF) Weakness
The 2015 WRX comes from the factory with a Dual-Mass Flywheel (DMF). The DMF contains internal springs designed to absorb torsional vibrations from the direct-injected FA20 engine, protecting the transmission gears from chatter. However, when you increase boost and torque via tuning, these internal springs frequently over-compress, rattle, and ultimately fail, sending metal shavings into your bellhousing.
According to long-term durability data shared by transmission specialists on NASIOC, converting to a Single-Mass Flywheel (SMF) is the most highly recommended upgrade for any tuned 2015 WRX. Below is a comparison of your flywheel options:
| Flywheel Type | Weight | Pros | Cons | Estimated Cost (2026) |
|---|---|---|---|---|
| OEM DMF (Subaru) | ~28.5 lbs | Smooth idle, zero gear rattle, OEM pedal feel. | Prone to internal spring failure when tuned; heavy. | $650 - $750 |
| Exedy Lightweight SMF | ~18.0 lbs | Faster revs, eliminates DMF failure point, reliable. | Introduction of gear rattle at idle; requires sprung hub. | $400 - $450 |
| ACT Streetlite SMF | ~21.5 lbs | Heat-treated, durable, slightly less rattle than Exedy. | Heavier than Exedy; still introduces some NVH. | $480 - $530 |
Expert Rule: If you convert to an unsprung SMF, you must pair it with a clutch disc that features a sprung hub (marcel springs) to absorb driveline shock. Pairing a solid-hub puck disc with an SMF on a street-driven WRX will accelerate transmission synchro wear and cause severe driveline shock.
Step 3: Selecting the Correct Push-Type Clutch Kit
With your flywheel strategy decided, it is time to select the clutch kit. Always verify that the kit explicitly states compatibility with the 2015-2021 WRX (Push-Type). Here are the top-tier recommendations based on extensive platform testing:
- Exedy OEM Replacement (Part # SBR101U): The gold standard for stock or lightly modified daily drivers. Exedy is the OEM manufacturer for Subaru, ensuring perfect fitment and factory-like engagement. (~$350)
- ACT Heavy Duty Organic (Part # SB11-HDSS): Features an HD pressure plate with an organic sprung disc. Ideal for Stage 2 WRXs making up to 380 lb-ft of torque. Retains daily-drivable engagement but with a heavier pedal. (~$550)
- Clutch Masters FX250 (Part # 16098-HD00): A fantastic hybrid setup utilizing a heavy-duty pressure plate and a Kevlar-organic hybrid disc. Excellent for aggressive street driving and occasional track days. (~$620)
- Exedy Stage 2 Cerametallic (Part # KSB102): Designed for 400+ WHP built FA20s. The ceramic puck design grabs aggressively and handles extreme heat, but it is entirely unsuited for stop-and-go traffic. (~$700)
Step 4: Sourcing Mandatory One-Time-Use Hardware
A professional-grade 2015 WRX clutch replacement requires replacing specific torque-to-yield (TTY) and wear-prone hardware. Do not reuse the following components:
- FA20 Flywheel Bolts (x8): These are TTY bolts. Reusing them risks them snapping inside the crankshaft under the FA20's high-torque loads. (OEM Part # 800210540).
- Clutch Fork Pivot Ball & Clip: The pivot ball wears a groove into the fork over time. Replacing it ensures proper clutch geometry and prevents premature release bearing wear.
- Release Bearing (Throw-out Bearing): Even if it feels smooth, the internal grease degrades under the heat of the FA20's turbo-backed exhaust proximity. Always replace it with an OEM Subaru or Exedy unit.
- Subaru Extra MT 75W-80 Gear Oil: The TY856 6-speed requires specific fluid for optimal synchro operation. Drain and refill with exactly 3.8 liters of OEM fluid (Part # SOA635075).
Step 5: Factory Torque Specifications for the 6MT
Proper torque sequencing is vital to prevent warping the flywheel or cracking the bellhousing. Always consult the official Subaru TechInfo Portal for the most up-to-date service manuals. Below are the critical torque specifications for the 2015 WRX FA20DIT and 6MT assembly:
| Component | Fastener Size / Type | Torque Specification | Notes |
|---|---|---|---|
| Flywheel to Crankshaft | M12 (TTY) | 51 lb-ft + 90° turn | Must use new OEM bolts. Tighten in a star pattern. |
| Pressure Plate to Flywheel | M8 x 1.25 | 18 lb-ft (25 Nm) | Tighten gradually in a crisscross pattern to avoid warping. |
| Bellhousing to Engine Block | M10 / M12 | 37 lb-ft (50 Nm) | Ensure alignment dowels are seated before tightening. |
| Transmission Crossmember | M12 | 52 lb-ft (70 Nm) | Verify engine/trans mounts are not sagging before final torque. |
| Front Axle Nuts | M24 | 140 lb-ft (190 Nm) | Use a new staked axle nut on both sides. |
Step 6: The Critical 500-Mile Break-In Protocol
The final, and most frequently ignored, step of a clutch kit selection and installation is the break-in procedure. Whether you chose an organic or cerametallic disc from Exedy Global, the friction material must be heat-cycled and bedded to the flywheel surface.
For the first 500 miles, avoid full-throttle launches, aggressive drag-strip starts, and prolonged stop-and-go traffic in hilly terrain. Perform moderate acceleration from 30 to 50 MPH in 3rd gear, then lift off the throttle and allow the car to engine-brake. This process generates the moderate, even heat required to cure the bonding resins in the friction material without glazing the disc. Skipping this step on a Stage 2 WRX will result in immediate clutch slip and void your manufacturer warranty.
Final Thoughts on the VA-Chassis Drivetrain
Upgrading the clutch on your 2015 WRX is a rite of passage for FA20DIT owners. By respecting the push-type architecture, eliminating the fragile DMF, and adhering strictly to TTY hardware protocols, you will build a drivetrain capable of handling the WRX's explosive torque curve for years to come. Always prioritize quality OEM hardware and reputable friction brands over budget internet kits—your transmission's synchros and your wallet will thank you.
