Mercedes W177/C118, A45/A45S/CLA45/CLA45S AMG Catless Downpipe With Heat Shield

Unlock the M139 in your Mercedes-AMG A45 S or CLA45 S with this catless performance downpipe, supplied as a two-piece system with full woven heat shielding across both sections.

The M139 is the most powerful series-production four-cylinder ever built, and in standard form the factory downpipe is the one thing most obviously holding it back. Replacing it is the first hardware step almost every tuned A45 S and CLA45 S takes, and on this engine it matters more than usual: the turbocharger sits at the back of the head, hard against the bulkhead, so a freer path out of the turbine has an immediate effect on how quickly it builds boost.

Manufactured from premium T304 stainless steel and precision TIG welded throughout, with heat shielding wrapped over the full length to keep radiant heat off the bulkhead and the components packed in around it.

Key Features

Catless Configuration
Removes the restrictive factory catalyst entirely for maximum exhaust flow and a much harder tone. (For off-road or track use only.)

Full Woven Heat Shielding
Both sections are wrapped, not just the elbow. On an engine with its turbo against the firewall that is a genuine requirement rather than a styling touch.

Premium T304 Stainless Steel
High-grade, corrosion-resistant material built to withstand the exhaust gas temperatures a tuned M139 produces.

Flexible Braided Joint
Absorbs engine movement and driveline flex so the system is not stressed at the turbo flange, a common failure point on rigid aftermarket pipes.

Two-Piece Design
Splits into two sections for installation, which matters in an engine bay this tightly packed.

Direct Bolt-On Fitment
Mounts to the factory turbo flange and mid section using the original brackets and hangers, with no cutting or fabrication required.

Performance Benefits (When Tuned)

• Increases of 30-40 HP and 50-70 Nm of torque

• Noticeably faster turbo spool and sharper throttle response

• Deeper, harder exhaust note with far more turbo and wastegate character

• Lower exhaust gas temperatures and reduced heat soak under sustained load

Vehicle Fitment

• Mercedes-AMG A45 / A45 S - W177 (2019-2025)

• Mercedes-AMG CLA45 / CLA45 S - C118 (2019-2025)

• Mercedes-AMG GLA45 S - H247 (2020-2025)

• 2.0L Turbocharged M139 Engine

M139 Only - This Will Not Fit an Earlier A45

The M139 turns the cylinder head around compared with the M133 that came before it. The intake sits at the front and the exhaust side faces the bulkhead, so the turbocharger is mounted at the back of the engine rather than the front. That is why the M139 makes so much more power from the same capacity, and it is also why the exhaust hardware is completely different.

This downpipe fits the W177, C118 and H247 cars only. If you have a W176 A45 or C117 CLA45, that is the M133 and it takes our W176/C117 downpipe instead. The two are not interchangeable in either direction.

Please Note

This is a catless downpipe intended for off-road or motorsport use only and may not comply with local emissions laws. An ECU tune is strongly recommended to realise the full benefit of the part and to manage the check engine light that removing the catalyst will otherwise trigger. Professional installation is recommended.

Why Choose Proven Performance Parts

We specialise in high-performance parts for European vehicles — Volkswagen GTI & R models, Audi S/RS platforms, BMW M cars and Mercedes-AMG. Every product we offer is carefully selected for its quality, fitment, and real-world performance — tested by enthusiasts, for enthusiasts.