4SRC Carbon Fibre Bonnet

For Subaru WRX STI (2015–2019)

The 4SRC carbon fibre bonnet is designed to improve both airflow efficiency and overall vehicle weight reduction for the Subaru WRX STI platform.

Featuring an aggressive central intake scoop, the bonnet allows increased airflow into the engine bay, supporting cooling performance whether the vehicle retains the OEM top-mounted intercooler or has been converted to a front-mounted setup.

Constructed using high-quality carbon fibre materials, this bonnet offers a balance of structural strength, reduced weight, and refined surface finish.

Construction & Options

We offer this bonnet in two configurations:

Single-Sided Carbon (Outer Carbon)

• Carbon fibre outer skin

• Inner structure finished in smooth matte black

• Clean, uniform internal surface (non-textured)

• Optimised balance between weight, cost, and durability

This is the most common choice for road and performance builds where exterior appearance and functionality are prioritised.

Double-Sided Carbon (Full Carbon Construction)

• Carbon fibre outer and inner structure

• Full exposed carbon weave on both sides

• Reduced overall weight compared to hybrid construction

• Higher material and manufacturing cost

Designed for customers who require a fully carbon construction, typically for high-end builds or weight-focused applications.

Functional Design

Large central intake scoop for increased airflow
Improved engine bay cooling efficiency
Lightweight construction compared to OEM bonnet
Direct replacement fitment

Fitment

Subaru WRX STI
Model Years: 2015 – 2019

Engineering Approach

At 4SRC, our focus is not only on appearance but also on correct construction and usable performance.

The single-sided carbon version retains a properly finished internal structure, ensuring durability and a clean OEM-like presentation when the bonnet is opened, while the double-sided version provides a fully exposed carbon solution for customers seeking maximum weight reduction and visual impact.