Catless Downpipe 2017-2025 BMW 320i/330i/420i/430i/520i/530i/Z4 - B48

A direct bolt-on catless downpipe for the BMW B48, built from 304 stainless steel and TIG-welded for a clean, durable fit. Replacing the restrictive factory catalytic converter frees up exhaust flow, spools the turbo sooner, and lets the B48 make the power it's capable of once tuned.

Replaces OE Part No. 18329797597

Specifications

• 304 stainless steel construction, TIG-welded
• Turbo side: 4.0 inch · Exhaust side: 3.0 inch
• Integrated thermal heat shield
• Direct bolt-on, no cutting or permanent modification

What it does

• Frees up exhaust flow by removing the factory cat, cutting backpressure so the turbo spools faster and holds boost more easily.
• Supports a tune, built for Stage 1, Stage 2 and beyond, letting a tuned B48 deliver its full horsepower and torque.
• Manages heat with the integrated shield, keeping exhaust heat inside the pipe to protect nearby wiring, sensors and intake parts and help hold lower EGTs under load.
• Sharpens the sound into a deeper, sportier exhaust note without constant cabin drone.

Build quality

Each downpipe is TIG-welded for clean seams, smooth internal transitions and reliable strength under high exhaust temperatures. It bolts directly to the factory location and works with both the stock and aftermarket exhaust systems. Backed by our Lifetime Replacement Guarantee.

Compatible Models

3 Series: 320i/330i (G20/G21 Pre-LCI & LCI, 2017-2025) · G28 LCI (2021-2025)
4 Series: 420i/430i (G22/G23/G26 Pre-LCI & LCI, 2019-2025)
5 Series: 520i/530i (G30/G31 LCI, 2019-2023)
X3: G01 Pre-LCI & LCI (2018-2024)
Z4: sDrive20i/30i (G29, 2017-2025)
Toyota Supra: 2.0 (A90, 2020-2025)