Audi S5/A5 B9 Prepreg Dry Carbon Fiber V2 Rear Diffuser

Engineered for Audi S5/A5 B9 pre-facelift (2016-2019) owners who want track-grade aggression, this Prepreg Dry Carbon Fiber V2 Rear Diffuser transforms the rear of your coupé, sportback, or cabriolet with motorsport-derived V-cut geometry while sharpening its aerodynamic character. Manufactured in Europe to factory-spec mounting tolerances and quality-controlled by BYC Performance, this Audi S5/A5 B9 carbon V2 rear diffuser bolts directly to OEM mounting points — no cutting, no drilling, no modification required.

If you're building a serious Audi A5/S5 B9 tuning project and want a part that goes well beyond the factory plastic diffuser, this V2 dry carbon rear diffuser is for you. Autoclave-cured prepreg carbon fiber is noticeably lighter than wet-lay carbon parts, with superior structural integrity and outstanding UV resistance. Designed to complement the S5 B9's 3.0 TFSI V6 single-turbo (354 hp) and the A5 B9's 2.0 TFSI EA888 four-cylinder, this aggressive V2 V-cut geometry is the ideal aesthetic and functional upgrade for both daily and show use.

Key Features

• Prepreg Dry Carbon Technology: Pre-impregnated carbon plies cured in an autoclave under high heat and pressure for homogeneous resin distribution and a consistent weave.
• Aggressive V2 V-Cut Geometry: Distinct from our standard flat-fin S5/A5 B9/B9.5 rear diffuser, the V2 features deep V-cut channels for a true motorsport look.
• High Strength: Carbon fiber offers very high strength for its weight, resisting stone chips and light contact.
• Aerodynamic Performance: Optimized diffuser channels guide underbody airflow and aid rear-axle stability at high speeds.
• 2x2 Twill Carbon Weave: Authentic carbon fiber pattern under a high-gloss UV-protective clear coat.
• Direct OEM Fit: Plug & play on factory Audi A5/S5 B9 pre-facelift (2016-2019) rear bumper mounts.
• UV & Chemical Protection: Long-life clear coat protects against fading, cracking, fuel splash, and road tar.

Prepreg Dry Carbon vs. Wet Carbon — Which Is Better?

Most aftermarket carbon parts are made using wet lay-up, where resin is applied by hand and cured at room temperature — which can leave air voids and inconsistent weight. Prepreg dry carbon:

• Cured in an autoclave under high heat and pressure → a more consistent weave
• Made with a controlled resin ratio → lighter and stronger
• The production method widely chosen in motorsport
• Minimal UV fading over years of use

Vehicle Fitment

This Audi S5/A5 B9 V2 rear diffuser fits the following models:

• Audi A5 Coupé B9 (2016, 2017, 2018, 2019) — 2.0 TFSI / 2.0 TDI
• Audi A5 Sportback B9 (2016-2019) — 2.0 TFSI / 2.0 TDI
• Audi A5 Cabriolet B9 (2017-2019) — same rear bumper as coupé/sportback (confirm bumper code before order)
• Audi S5 Coupé B9 (2016-2019) — 3.0 TFSI V6 (354 hp)
• Audi S5 Sportback B9 (2016-2019) — 3.0 TFSI V6
• Audi S5 Cabriolet B9 (2017-2019) — 3.0 TFSI V6

Important notes:

• NOT compatible with B9.5 facelift (2019-2024) — the 2019 facelift changed rear bumper geometry; a separate B9.5 diffuser is available.
• NOT compatible with RS5 B9 — RS5 has unique aggressive rear bumper geometry.
• NOT compatible with previous-generation B8/B8.5 A5/S5 (2008-2015).
• Distinct from our standard flat-fin S5/A5 B9/B9.5 rear diffuser — this V2 fits B9 pre-facelift only and features aggressive deep V-cut channels.

Technical Specifications

• Material: Prepreg Carbon Fiber (2x2 Twill Weave)
• Manufacturing: Autoclave Cure
• Finish: High-Gloss Clear UV-Protective Resin
• Color: Natural carbon weave black
• Origin: Europe

Installation Notes

Installing the Audi S5/A5 B9 carbon V2 diffuser is a direct replacement of the factory part. Professional installation is recommended:

1. Raise the vehicle and remove rear bumper underbody screws.
2. Detach the OEM plastic diffuser from clips and bolts.
3. Test-fit the carbon V2 diffuser for alignment.
4. Secure with supplied hardware to the manufacturer's recommended torque.
5. Verify exhaust tips are centered in diffuser cutouts (S5: quad oval; A5: single/dual).

Care & Maintenance

Wash with pH-neutral car shampoo. Apply carbon-safe sealant every 6 months. Keep pressure washer nozzle at least 30 cm from surface.

FAQ

Does this fit the B9.5 facelift (2019-2024)?
No. The 2019 facelift changed the rear bumper geometry. A separate B9.5 diffuser is available.

Does this fit the RS5 B9?
No. RS5 B9 has unique rear bumper geometry and is not compatible with this V2 diffuser.

How is this different from your standard S5/A5 B9/B9.5 rear diffuser?
The standard S5/A5 B9/B9.5 rear diffuser is a flat-fin profile that fits both B9 and B9.5. The V2 fits B9 pre-facelift only and features aggressive deep V-cut channels for a motorsport look.

Compatible with Coupé, Sportback, and Cabriolet?
Coupé and Sportback share rear bumper architecture and are both compatible. For Cabriolet, please verify your bumper code before ordering.

Compatible with previous B8/B8.5 A5?
No. B8/B8.5 (2008-2015) uses different chassis and bumper geometry.

Will rain damage dry carbon parts?
No. Autoclave-cured prepreg carbon is fully waterproof and weather-resistant.

Shipping time?
In-stock items ship within 1-3 business days via partner couriers. International shipping available.

Warranty?
BYC Performance offers a 12-month manufacturer warranty.

Why BYC Performance?

BYC Performance is a Turkey-based performance tuning specialist sourcing premium carbon fiber parts from leading European manufacturers. Our catalog includes Audi RS carbon diffusers, Audi S5/A5 carbon parts, BMW M3 carbon diffusers, Porsche carbon spoilers, and many more. All parts are sourced from leading European manufacturers and undergo strict quality control.