Exhaust› Catalytic Converters

CTS Turbo

4.5" to 3.15" High-Flow Catted Downpipe

$459.99

SKU: CTS-EXH-DP-0024

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Special Order
Ships in 4–6 weeks
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$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The CTS Turbo 4.5" High-Flow Cat is a downpipe designed for BMW B58 engines. It is constructed from T304 stainless steel and features TIG welded, back-purged construction for durability. This downpipe includes a high-flow 200-cell catalytic converter and measures 4.5" in diameter, reducing to 3.15" (80mm) to fit factory or aftermarket exhaust systems.
Show original supplier description
The CTS Turbo High-Flow Catted Downpipe is engineered to significantly improve exhaust flow and unleash the performance potential of your BMW B58 engine. Constructed from premium T304 stainless steel, the downpipe features robust hand TIG welding with back-purging, ensuring long-term reliability and performance. It measures 4.5 inches in diameter, tapering down to 3.15 inches (80mm) to ensure a perfect fitment with either the factory or an aftermarket exhaust system. The integrated high-flow 200-cell catalytic converter offers an improved flow rate over stock while still providing emissions control. The product is confirmed to fit both Rear-Wheel Drive (RWD) and xDrive all-wheel-drive models. A 12-month warranty is included, covering manufacturing defects. Please note that installing this downpipe may trigger a Check Engine Light (CEL). Proper tuning software is required to address this. Applications include the 2016-2019 BMW 340i, 440i, 540i, 740i, M140i, and M240i, all equipped with the B58 engine.
Vehicle Symptoms
  • Check engine light on (P0420)
  • Sluggish acceleration & loss of power
  • Decreased fuel economy
  • Exhaust odor or sulfur smell
  • Poor turbo response / lag
Diagnostic Codes
  • P0420 – Cat Sys Efficiency Below Threshold (B1)
Relevant Conversations
  • BMW B58 P0420 fix – replace downpipe?
  • B58 4.5" high-flow cat downpipe review
  • CTS Turbo B58 downpipe install time
  • Will aftermarket downpipe cause CEL on B58?
  • Best downpipe for B58 2024
  • B58 downpipe vs stock – power gains
  • How to install CTS Turbo B58 downpipe
  • B58 downpipe with tune – experience
  • P0420 B58 catalytic converter replacement
  • B58 exhaust upgrade – downpipe & cat-back

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandCTS Turbo
Part NumberCTS-EXH-DP-0024
CategoryExhaust
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Shipping

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