Turbo Downpipe Exhaust for Subaru GT35 & GT35R 3 Inch

FLASHARK Turbo Downpipe Exhaust for Subaru GT35 & GT35R 3 Inch

Flashark's GT35/GT35R downpipe is engineered to replace the restrictive factory downpipe on Subaru EJ-series engines running a Garrett GT35 or GT35R turbocharger upgrade. Positioned between the turbocharger turbine outlet and the exhaust system, this 3-inch high-flow downpipe eliminates the factory bottleneck—reducing backpressure, improving turbo spool response, and unlocking the power your GT35 turbo is capable of delivering.

Built from stainless steel with computerized mandrel bends, TIG-welded joints, and a CNC-machined flange, this downpipe is designed for 350–450 WHP builds where every bit of exhaust flow matters.

Note: ECU tuning is required after installation. This downpipe is intended for off-road / track use. Check local emissions regulations before purchase.

Fitment

Direct Fit For:

• Subaru WRX STI (EJ257) — 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
• Subaru WRX (EJ255) — 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014

Requires: Garrett GT35 or GT35R turbocharger with T3 turbine housing flange. Not compatible with: Stock VF-series or TD04 turbochargers (different flange pattern).

Not sure about fitment? Email us at support@flasharkracing.com with your year, model, and turbo specs — we'll confirm within 24 hours.

Features:

1. Improve Engine Output and Efficiency, Give you extra HPs, and increases torque
2. Large diameter and free flow tubing for unrestricted flow, Making the exhaust air flow smooth, Designed for high-performance racing
3. Made of High-Quality Stainless Steel with Computerized Mandrel-Bends
4. All joints are TIG welded to prevent cracking and wear
5. CNC Machine Flange for MAX Strength and Durability
6. Flanges chrome plated for corrosion resistance

What Does This Downpipe Do?

The downpipe is the critical exhaust section between your turbocharger's turbine wheel and the rest of the exhaust system. The factory EJ257 downpipe is 2.5" with a restrictive catalytic converter—it's the single biggest exhaust bottleneck on a GT35-powered build.

By replacing it with Flashark's full 3" high-flow downpipe:

• Backpressure drops significantly → turbo spools faster, holds boost longer
• Exhaust gas temperature (EGT) drops → safer for high-boost tuning
• Mid-range torque improves → the GT35's sweet spot becomes accessible
• Power gains: 150–200 WHP over stock (GT35 + downpipe + proper tune)

Designed for: Garrett GT35 (standard bearing) and GT35R (ball-bearing) turbochargers with T3 turbine housing flange.

Q1: What's the difference between GT35 and GT35R?

A: GT35 uses standard journal bearings; GT35R uses ball-bearing cartridges for faster spool and higher RPM capability. Both share the same T3 turbine flange, so this downpipe fits both.

Q2: Catless or catted?

A: This downpipe is catless (no catalytic converter) for maximum flow. If you need a catted version for street legality, contact us — we can advise on high-flow cat options.

Q3: Do I need supporting mods?

A: For a safe 350–450WHP build: upgraded fuel pump (Walbro 255LPH+), 1000cc+ injectors, front-mount intercooler, blow-off valve, and standalone ECU tuning are strongly recommended.

Q4: Can I install this myself?

A: Yes, if you have mechanical experience and proper tools. Plan 3–5 hours. Subaru exhaust hardware seizes easily — penetrating oil and heat are your friends. If unsure, have a shop install it.

Q5: What exhaust does this connect to?

A: 3" outlet mates to any 3" cat-back exhaust. If your exhaust is 2.5", you'll need an adapter or to upgrade your cat-back to 3".

Q6: Will this trigger a Check Engine Light?

A: Possibly — removing the cat and changing the O2 sensor placement can trigger codes. A tuned ECU can disable or adjust for this. The included O2 bung supports the installation of a wideband sensor for proper tuning.

Q7: How does this affect exhaust sound?

A: Catless + larger diameter = more aggressive. You'll hear more turbo spool, blow-off valve, and deeper boxer rumble. Volume increase is noticeable but not obnoxious with a quality cat-back.

Q8: Is this worth it over a cheaper downpipe?

A: Cheap downpipes often use thin 409 stainless (rusts), have poor weld quality (cracks under heat cycling), or incorrect flange geometry (exhaust leaks). Flashark uses real T-304, full TIG welds, and CNC flanges — it's built to last.