2021 SUBARU STI · BUILT EJ · COBB
Thomas’s 2021 STI.
A dark-blue STI built around an IAG closed-deck engine, an ETS rotated turbo kit and a Garrett GTX3576R. I calibrated Thomas’s combination through the COBB Accessport.
Discuss my STI build →
- THE CAR
- Thomas’s 2021 STI
- ENGINE MANAGEMENT
- COBB Accessport · tuned by Keith
- TURBOCHARGER
- Garrett GTX3576R · ETS rotated kit
THE COMBINATION
More than a turbo swap.
The archived build specification pairs an IAG Stage 2.5 closed-deck engine with Kelford 280/282 cams and the Garrett turbo. An ACT twin-disc clutch supports the drivetrain side of the project. The combination was set up for 93-octane and E85 fuel.
AWD’s original public feature identifies the car as a built 2021 STI and names the IAG closed-deck engine, ETS turbo kit and GTX3576R. Its installed-turbo photograph also appears in Thomas’s named project archive.
- ENGINE
- IAG Stage 2.5 closed deck
- CAMSHAFTS
- Kelford 280/282
- CLUTCH
- ACT twin disc
- FUEL SETUPS
- 93 octane & E85
- EXHAUST HARDWARE
- G-Sport 400 Gen 2 GESI catalyst
- CALIBRATION
- Keith Fields · COBB Accessport
This is a record of Thomas’s combination. For a new project, I review the exact model year, ECU software, fuel system and hardware before recommending a calibration path.
FROM THE ORIGINAL FEATURE
The installed Garrett and ETS combination.
See the finished turbo installation in AWD Tuning’s original 2021-STI feature.
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THE CAR OVER TIME
The early result was one stage.
- May 2022 wheel horsepower
- 576.8 whp
- May 2022 wheel torque
- 475.6 lb-ft
The original Mustang summary report for Thomas’s 2021 STI records 576.8 hp at 7,333 rpm and 475.6 lb-ft at 5,470 rpm, with weather correction, from the May 13, 2022 session. The earlier marketing graphic rounded the build’s output to 575 whp and 470 lb-ft. This was one stage of the project, not its final output.
Later development
I recall Thomas’s STI later reaching approximately 611 whp. The dated sheet for that later session is being matched to the archive; the earlier torque figure is not being carried over to that result.
Planning a built-engine STI?
Tell me about your engine, turbo, injectors, fuel system, ECU and intended use. We can establish what the car needs for calibration and coordinate remote support, road tuning or a customer-arranged dyno session.
Ask Keith about my build →