Brett’s everyday STI.

THE PROJECT

Keep the focus on the drive.

Brett’s STI was previously on an Accessport. He had experienced recurring P0420 faults, including with the stock downpipe fitted, and opted for a different engine-management solution.

The aim was a well-driving STI with minimal intrusion. ECU selection and calibration were part of that project; the dyno figures document the tuning sessions, rather than a diagnosis or repair of the catalyst fault.

MARCH 5, 2026 · AWD PROJECT ARCHIVE

A response-focused turbo plan.

AWD’s named post for Brett’s 2020 STI documents a COBB TD05H-20G prepared for installation, with low- and mid-range response part of the upgrade’s intended appeal.

The post records that stage of the project; it does not establish the installed hardware for every later tuning session.

Read AWD’s original Brett STI post ↗

MARCH 2026 · MUSTANG DYNO

Two fuels. Two recorded sessions.

Weather-corrected peak values from the original AWD Tuning Mustang summary reports, both printed March 29, 2026. Fuel labels come from the named source files. These are separate fuel sessions, not an Accessport-versus-Haltech comparison.

PLANNING YOUR STI

Start with the whole car.

Tell me your model year, current ECU, fuel, hardware and what you want to improve. Include any warning lights or mechanical issues so we can establish the right scope before selecting a management system or booking tuning.

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