$595.00 USD
$595.00 USD






Unlock hidden performance and improve turbo response with the MAD Catted Downpipe, specifically designed for U.S.-spec BMWs equipped with the B46 engine. This high-performance upgrade offers increased airflow, reduced turbo lag, and a sportier exhaust tone while maintaining emissions-conscious functionality for off-road and track use.
The integrated high-flow catalytic converter significantly lowers exhaust restriction compared to the factory downpipe, allowing your turbo to spool faster and produce more power. On tuned vehicles with the factory turbocharger, expect gains of up to 30 horsepower, with even greater improvements possible with upgraded turbo setups.
The inclusion of a flex section ensures durability by reducing stress from engine movement and thermal cycles. Engineered for precision and longevity, the MAD B46 downpipe is a bolt-on solution that delivers consistent results.
High-Flow Catalytic Converter
Improves exhaust flow and supports higher horsepower while remaining emissions-conscious for off-road use.
Up to 30 Horsepower Gains on Stock Turbo
Increased performance, improved throttle response, and reduced turbo lag.
Mandrel-Bent Construction
Smooth bends eliminate restriction for maximum exhaust velocity and a deeper exhaust note with no drone.
Reinforced Flex Section
Enhances durability by absorbing engine movement and thermal expansion.
Direct Bolt-On Installation
Designed for a seamless fit using OEM mounting points. No cutting or fabrication required.
Left- and Right-Hand Drive Compatible
Versatile fitment across multiple chassis and drivetrain configurations.
Built for U.S.-Spec B46 Engines
Not compatible with vehicles equipped with OPF (Gasoline Particulate Filter).
Material: Stainless Steel
Catalyst: Integrated High-Flow Cat
Fitment: Direct Bolt-On
Power Gains: Up to 30 HP on tuned stock turbo setups
Warranty: Lifetime warranty on fitment and manufacturing defects
Shipping Time: 1–2 business days
Return Period: 90 days
High-flow 200 cell catalytic converter
For U.S.-spec BMWs with the B46 engine only. Not compatible with vehicles equipped with OPF.
BMW 1 Series: 2016+ 120i, 125i
BMW 2 Series: 2016+ 220i, 230i
BMW 3 Series: 2016+ 320i, 330e, 330i (F30, G20, etc.)
BMW 4 Series: 2016+ 420i, 430i
BMW 7 Series: 730i (B46 engine only)
TOYOTA SUPRA 2020+ 2.0
Disclaimer:
This product is intended for off-road or racing use only. It is not certified for use on public roads and may not comply with local, state, or federal emissions regulations. Please verify local laws before purchase or installation.
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$595.00 USD
$595.00 USD
This product can expose you to chemicals such as lead and lead compounds, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
For a complete list of chemicals known to cause harm, visit https://www.p65warnings.ca.gov/chemicals.
Under the federal Clean Air Act (42 U.S.C. §7522(a)(3)), it is illegal to manufacture, sell, install, or use any part that defeats or alters a motor vehicle’s emission control system for use on public roads. Unless a product has received an Executive Order (EO) from the California Air Resources Board (CARB), it is not legal for use or installation on any pollution-controlled vehicle driven on public highways.
Some states have CARB-equivalent or independent emissions laws. Customers are responsible for verifying local regulations before purchasing or installing emissions-related products.
All performance, racing, or competition parts sold by this company are intended solely for off-road, closed-course, or competition use on vehicles that are never registered or used on public highways.
Kies Motorsports, LLC sells and markets these products for lawful use only. We do not condone or authorize the use of emission-control defeat devices or any modification that violates the Clean Air Act or state regulations.