BMW M5 F90 / M8 F92 Heat-Shielded Stainless Steel De-cat Downpipe

Engineered for BMW M5 F90 and M8 F92 Coupé owners, this Heat-Shielded De-cat Downpipe removes the OEM catalyst entirely for maximum turbo outlet flow, while the heat-shield coating supports engine bay thermal management. Manufactured in Europe and quality-controlled by BYC Performance.

The F90 M5 + F92 M8 share the S63B44T4 4.4L V8 biturbo (600-625 hp). The de-cat downpipe eliminates catalyst restriction entirely for aggressive turbo spool, a deeper exhaust note, and contributes to power gains with a proper tune. The heat-shield coating noticeably lowers engine bay temperatures — critical thermal protection for track use.

Key Features

• Full De-cat (No Catalyst): Maximum turbo outlet flow, aggressive spool.
• Heat-Shield Coating: Noticeably lowers engine bay temperatures.
• T304 Stainless Steel: Lifetime rust-resistance.
• Maximum Flow: Noticeably less backpressure than the 200-cell variant.
• CNC-Bent Piping: Smooth internal surface, flow-optimized geometry.
• V-Band Connections: Direct turbo and catback connection.
• Tune Required: De-cat may trigger MIL — a custom ECU tune is recommended.

F90/F92 Downpipe Lineup — Three Variants

• 200-Cell Catalyzed Heat-Shielded: Emissions-preserved
• De-cat Heat-Shielded (this product): Max flow + heat shield, track-focused
• De-cat Standard (no heat shield): Most affordable, no thermal protection

Vehicle Fitment

This BMW M5 F90 / M8 F92 de-cat downpipe fits the following models:

• BMW M5 F90 Sedan (2018-2024) — S63B44T4 600 hp
• BMW M5 F90 Competition (2018-2024) — 617 hp
• BMW M5 F90 CS (2021 limited) — 625 hp
• BMW M5 F90 LCI (2020-2024)
• BMW M8 F92 Coupé (2019-2025) — S63B44T4 600 hp / 617 hp Competition

Important notes:

• BMW M8 F93 Gran Coupé and F91 Convertible share the S63B44T4; geometry likely compatible. Verify before ordering.
• NOT compatible with the BMW M5 F10 / M6 F06 (S63B44T2).
• NOT compatible with the BMW M5 E60 (S85 V10).
• De-cat is subject to street-legality restrictions; intended for track or closed-course use only.

Technical Specifications

• Material: T304 Stainless Steel
• Catalyst: None (de-cat)
• Heat Insulation: Thermal coating
• Connections: Turbo outlet + catback v-band
• Manufacturing: CNC-bent, robotic welded
• Origin: Europe

Installation Notes

1. Lift the vehicle, access the downpipe area from below.
2. Disconnect the OEM downpipe v-band clamps and oxygen sensor connectors.
3. Remove the OEM downpipe + primary catalyst.
4. Align the new de-cat downpipe to the turbo flange, torque v-band (12 Nm).
5. Install oxygen sensors in the bosses (lambda spacer or tune recommended).
6. Torque the catback v-band.
7. Inspect for leaks.
8. Install custom ECU tune.

Care & Maintenance

Re-check bolt torque after first 500 km. Replace heat-shield coating if damaged.

FAQ

Does it fit the F10/F06?
No.

Does it fit the E60?
No.

Does it fit the M8 F93 / F91?
Same S63B44T4; geometry likely compatible. Verify before ordering.

Is a tune required?
Yes. De-cat triggers MIL — custom ECU tune is recommended.

How much more power vs the 200-cell?
De-cat delivers more flow and a deeper, louder exhaust note.

How does it differ from the non-heat-shielded version?
This product includes the heat-shield coating — noticeably lowers engine bay temperature.

Shipping time?
1-3 business days via partner couriers.

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

Why BYC Performance?

BYC Performance is a Turkey-based performance tuning specialist sourcing premium exhaust parts from leading European manufacturers. Our catalog includes BMW M5 F90 de-cat downpipe, BMW M8 F92 heat-shielded downpipe, BMW M decat, and more.