This Alpha Competition decat Downpipe has been developed for BMW B58 models with OPF and offers a significant improvement in exhaust gas flow compared to the original Downpipe. Thanks to the large diameter (4" to 3"), back pressure is reduced, resulting in faster turbo response, increased power and a more aggressive exhaust note.
The Downpipe is manufactured from high-quality T304 stainless steel and is fully TIG-welded for maximum durability. A stainless steel heat shield is available as an optional extra for additional protection against radiant heat.
Benefits
• Reduced exhaust back
pressure• Faster turbo
Spool-up• Increased power and torque•
More aggressive exhaust
note• High-quality T304 stainless steel construction•
Handcrafted and
TIG-welded• Plug-and-play installation•
Lifetime warranty•
Optional stainless steel heat shield available
Technical specifications
• Type: decat
Downpipe• turbo-side diameter: 4" (100 mm)
• exhaust-side diameter: 3" (76 mm)
• Material: T304 stainless steel•
Manufacture:
hand-made• Welding:
TIG-welded• Fitting: direct fit
Compatibility
• BMW M240i G42 B58
OPF• BMW M340i G20 / G21 B58
OPF• BMW M440i G22 / G23 / G26 B58 OPF
Please note
• Not suitable for the facelifted BMW M240i G42 produced from
05/2026• This newer version features an additional pressure connection in the original exhaust system
Contents
• Alpha Competition decat
Downpipe• fitting kit
Frequently Asked Questions
Does this fit all M240i G42 models?
No, it does not fit models produced from May 2026 onwards with the new exhaust configuration.
Is software required after fitting?
Yes, ECU software is recommended for optimum performance and to prevent fault codes.
What is the benefit of a decat Downpipe?
Reduced back pressure, faster turbo response and increased power.
Are fitting parts included?
Yes, all necessary fitting parts are included.
