Product Specifications
BMW B48 Catless Downpipe for Selected 2016–2021 Models
A less restrictive exhaust path can give a modified B48 a quicker, more direct response while adding a deeper and more noticeable exhaust tone. This Flashark catless downpipe is designed for selected 2016–2021 non-US BMW models equipped with the 2.0L B48 TwinPower Turbo engine and a compatible non-OPF exhaust layout.
The straight-through stainless steel pipe replaces the factory catalytic-converter section between the turbo outlet and the remaining exhaust system. It uses mandrel-bent tubing, TIG-welded joints and pre-welded oxygen-sensor ports.
Specifications
| Product Type | Catless Turbo Downpipe |
|---|---|
| SKU | FLJN-EXS22-00043003 |
| Engine Compatibility | BMW B48 2.0L TwinPower Turbo |
| Vehicle Market | Selected non-US vehicles only |
| OPF Compatibility | Not compatible with OPF-equipped vehicles |
| Drive Position | LHD intended layout; RHD steering-column clearance check required |
| Material | Stainless steel |
| Construction | Mandrel-bent tubing with TIG-welded joints |
| Oxygen-Sensor Ports | Pre-welded O2 sensor bungs |
| Exhaust Connection | Designed to connect to the compatible factory exhaust layout or a compatible aftermarket exhaust |
Key Features
Catless Straight-Through Design — Eliminates the factory catalytic converter, the B48's largest exhaust restriction. Unrestricted flow from the turbo outlet means faster spool, lower EGTs, and measurable power gains — especially above 3,000 RPM where the OEM cat is most restrictive
25–30 WHP Gains with Stage 2 Tune — Dyno-validated power increase when paired with a proper ECU tune (BM3, MHD, or bootmod3). The catless downpipe + tune is the single highest-ROI modification on the B48 platform
Mandrel-Bent Stainless Steel Piping — Smooth radius bends maintain consistent inner diameter through every curve — no crush-bent restrictions, no turbulence pockets. TIG-welded joints for leak-free sealing under boost
Direct Bolt-On for LHD Models — Precision-engineered to replace the factory downpipe using OEM mounting points and flange patterns. No cutting, no welding, no fabrication required on Left-Hand Drive models
Universal Cat-Back Compatibility — Bolts to both the stock OEM cat-back and all aftermarket exhaust systems (Akrapovič, Remus, Armytrix, etc.). No adapter needed
Pre-Welded O2 Sensor Bungs — Factory O2 sensors thread directly into the pre-welded bungs at the correct depth and position. No drilling, no welding — simply transfer the sensors from the stock pipe
Aggressive Exhaust Note — The catless design unlocks the B48's turbo spool whistle and deeper exhaust tone. More aggressive on throttle, sporty pops and burbles on deceleration — without the highway drone that plagues poorly designed systems
Built for Better Exhaust Flow and Sound
The factory downpipe routes exhaust gases from the turbo through a catalytic converter before they enter the rest of the exhaust. This catless B48 downpipe replaces that section with a more open path, helping exhaust gases leave the turbo more freely.
Drivers can expect a sharper exhaust character and more audible turbo sound. Final volume, rasp, burble and cabin drone depend on the remaining exhaust components, ECU calibration and whether the vehicle retains its factory resonator and muffler.
| Area | Factory Downpipe | Flashark Catless Downpipe |
|---|---|---|
| Catalyst | Factory catalytic-converter section retained | Straight-through catless path |
| Exhaust flow | More restricted through the catalyst section | Less restrictive turbo-outlet path |
| Sound | Quieter factory character | Deeper, louder tone with more audible turbo sound |
| Emissions behavior | Factory catalyst and monitoring retained | May trigger a catalyst-efficiency warning and is not intended for emissions-controlled street use |
| Exhaust smell | Catalyst helps reduce raw exhaust odor | More noticeable exhaust odor should be expected |
Installation, Tune and System Effects
Installation requires removal of the factory downpipe, transfer of the original oxygen sensors and inspection of the turbo-side and exhaust-side connections. Work around the turbo, sensors and exhaust fasteners is best handled with the vehicle safely raised and the exhaust fully cooled.
An ECU tune is not required to physically install the downpipe. A catless downpipe can, however, trigger an emissions-related check-engine light. Calibration choices, vehicle diagnostics and local emissions requirements should be discussed with a qualified BMW tuning professional.
Right-hand-drive cars need additional attention around the steering-column area. Stop the installation if the pipe contacts the steering system, bodywork or nearby components.
Who This Downpipe Is For
- Owners of a listed non-US BMW with a compatible B48 non-OPF exhaust layout
- Drivers building a performance, track or competition-oriented B48 setup
- Owners who want a less restrictive downpipe and a more aggressive exhaust character
- Drivers who understand the possible CEL, odor, sound and emissions tradeoffs of a catless system
Who Should Choose a Different Option
- US-spec BMW owners
- Vehicles equipped with an OPF or a different factory downpipe connection
- Drivers who require an emissions-compliant or street-legal replacement
- Owners who want minimal exhaust smell, factory-level sound or the lowest possible risk of a catalyst-efficiency warning
- Vehicles whose year, engine, market specification or exhaust layout does not match the listed fitment
Emissions and Street-Use Notice
Removing a catalytic converter can affect emissions compliance and may not be legal for public-road use. This product is intended for off-road or competition use where permitted. Check the rules that apply in your location before purchase and installation.
Shipping Information:
- Delivery Time: 3–5 business days
- Shipping: Free Shipping
Shipping & Returns
Free U.S. Shipping: Orders are typically processed within 1–2 business days and delivered within 7–9 business days. Additional charges may apply to remote areas.
30-Day Returns: Unopened and unused items in their original packaging may be returned within 30 days of receipt. Return shipping is covered for verified quality issues.
Worry-Free Delivery: Optional protection against eligible loss, theft, delay, or transit damage is available at checkout.
Duration of Warranty: 1 Year
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