Milltek Sport BMW B58 (G-Series)/ Toyota Supra (A90) High Flow Downpipe

Milltek Sport BMW B58 (G-Series)/ Toyota Supra (A90) High Flow DownpipeMilltek Sport BMW B58 (G Series) Toyota Supra (A90) High Flow Downpipe The Milltek Sport high flow downpipe is a direct upgrade for the BMW B58 (G Series) and Toyota Supra (A90), designed to free up the restrictive factory downpipe and let the turbocharged straight six breathe properly. With a larger 90mm bore and smoother internal flow, exhaust gases exit the turbo more efficiently, supporting stronger power delivery, sharper throttle response and a

Milltek Sport BMW B58 (G-Series) / Toyota Supra (A90) High Flow Downpipe

The Milltek Sport high flow downpipe is a direct upgrade for the BMW B58 (G-Series) and Toyota Supra (A90), designed to free up the restrictive factory downpipe and let the turbocharged straight-six breathe properly. With a larger 90mm bore and smoother internal flow, exhaust gases exit the turbo more efficiently, supporting stronger power delivery, sharper throttle response and a deeper, more characterful exhaust note.

The downpipe is available in two configurations to suit different builds and driving environments. Choose the version that best matches your needs and local regulations.

Off Road/Motorsport Use Only

This product does not have EC type-approval and alters a factory emissions control device. It may not pass emissions laws and tests in your country. 

Available Options

• 200 CPSI Race Cat (SSXTY168) – Uses a high-flow 200 cell sports catalytic converter to reduce back pressure compared with the OEM cat, while still providing some emissions control. A balanced choice for road-driven cars wanting more performance without going fully de-catted.
• Decat (SSXTY119) – Removes the catalytic converter entirely for maximum flow and the most aggressive sound. Intended for off-road or track use only.

Why Fit a Larger Bore Downpipe?

The downpipe is the first section of exhaust after the turbo, and the OEM part is one of the most restrictive components in the system. Replacing it with a larger diameter, mandrel-bent pipe reduces back pressure (the resistance the engine works against to push gases out). On the B58 platform, this is particularly effective because the engine responds well to improved exhaust flow, especially when paired with an ECU remap.

Expected benefits include:

• Improved turbo spool and throttle response
• Greater potential power gains, particularly when tuned
• A deeper, fuller exhaust tone with more turbo presence
• Better compatibility with stage tuning and full Milltek cat-back systems

Build Quality

Manufactured in the UK from high grade stainless steel, the downpipe uses TIG welded construction and mandrel bends to maintain a consistent internal diameter throughout. It is engineered as a direct bolt-on replacement, retaining factory mounting points and sensor bungs for a clean fit.

Technical Specification

Important: This is classified as a race product and is not E-marked. The decat version is intended strictly for off-road or track use and is not legal for road use in many regions. Always check local regulations before fitting. A supporting ECU remap is strongly recommended to get the most from this downpipe and to manage any cat-related fault codes.