Toyota GR Supra ARD Prepreg Race Diffuser 2020+

The ARD race diffuser for the GR Supra is ADRO's motorsport rear diffuser, made in prepreg carbon for strength at low weight. It's designed to work with ARD front aero and the Supra's factory rear bumper. Send us your model year so we can confirm fitment before ordering.

Aero over aesthetic. Function over form. Purpose over compromise.

What is ARD?

ARD is ADRO Racing Division, the company's motorsport engineering arm, aimed at cars that spend real time on track. Each ARD part is developed in CFD and tested on track before it goes on sale. ADRO's head of aerodynamics, Scott, comes from a Formula 1 development background and leads ARD's work. The GR Supra ARD Aero Package is one of the first complete systems from ARD.

The Rear Diffuser

A diffuser works by taking the high-velocity, low-pressure air traveling under the car and gradually expanding it back to ambient pressure before it exits at the rear. Done correctly, this expansion accelerates the flow ahead of it, increasing suction across the entire underbody. Done incorrectly, or with gaps and interruptions in the undertray that allow turbulent air to mix in, the pressure recovery breaks down and the diffuser produces a fraction of what it should.

The ARD rear diffuser is developed as the endpoint of a complete underbody system, not a standalone component bolted to the rear bumper.

How It Works

The diffuser undertray seals the gaps that cause turbulent recirculation under the car. On a stock Supra, those gaps allow high-pressure air to bleed into the underbody from the sides and center, disrupting the low-pressure environment the diffuser depends on. Blocking them keeps underbody velocity high across the full floor, which means the diffuser strakes have clean, fast-moving air to work with rather than recovering from turbulence upstream.

The strakes inside the diffuser generate vortices that roll along the diffuser surface, energizing the boundary layer and preventing flow separation as the channel expands. This is what allows the diffuser to extract more work from the airflow without stalling. Those vortices are stronger because of what happens upstream: the ARD undervanes generate large-scale vortices that feed conditioned, high-velocity flow rearward through the floor, arriving at the diffuser inlet with enough energy to drive the expansion process effectively.

As part of the complete ARD Aero Package (in ADRO bumper configuration), the system generates 2148N (483 lbs) of downforce at 180 km/h, a 1618% increase over the GR Supra's stock 125N, with a gain of +2023N (455 lbs) and a 45/55 front-to-rear balance.

Material

All ARD parts are made in prepreg carbon fibre. Prepreg carbon comes with the resin already impregnated into the fibre in controlled conditions, so the resin is spread evenly through the whole part. That makes the part lighter and stiffer, without weak or resin-heavy patches that could delaminate under load.

For a rear diffuser, panel stiffness affects more than durability. A diffuser channel that flexes under load changes its expansion geometry, which alters the pressure gradient the strakes are working against. Prepreg holds the designed geometry at speed and under heat, so the diffuser performs consistently across a full session rather than degrading as conditions change.

Vehicle Fitment

• 2020-2026 Toyota GR Supra
• 2026 Toyota GR Supra Final Edition
• Compatible with our GR Supra A90 Carbon Fibre Rear Diffuser

Send a few photos of your car to addison@sl-autowerkes.com and we'll confirm fitment before you order.

Before you paint or fit it

Check the packaging label against your order when the part arrives, and do a full test fit before any paint or installation. Returns and warranty claims aren't accepted on parts that have been altered or are no longer new and resalable.

See our GR Supra upgrade guide for where we would start on an A90.

More parts for the Toyota GR Supra A90: Front Lip V2 for Toyota GR Supra 2019+ and ZO Style Roof Spoiler for Toyota Supra 2019+. See all Toyota GR Supra A90 parts.