BMW performance RSS

The BMW F90 M5 uses the S63B44T4 — a 4.4-litre twin-turbo V8 that produces 591–617 HP from the factory depending on variant. It is one of the most potent sedans ever built, and it has substantial untapped potential locked behind factory exhaust restrictions. The stock catalytic converters downstream of each turbocharger are the primary bottleneck, and replacing them with performance downpipes is the foundation of any serious M5 build. Why the S63 Needs Downpipes The S63 positions its two twin-scroll turbochargers outboard of the cylinder banks in a traditional hot-outside-vee layout. Each turbo feeds exhaust through its own catalytic converter...

The BMW G80 M3 and G82 M4 are powered by the S58 3.0-litre twin-turbo inline-six — BMW M Division’s most potent six-cylinder production engine. With two mono-scroll turbochargers, a closed-deck block, and forged internals from the factory, the S58 is engineered to handle serious power. But the stock exhaust system, specifically the catalytic converter section immediately downstream of the turbos, is the single biggest restriction holding it back. This guide covers everything about upgrading the downpipe on the G80/G82 platform. The S58 Exhaust Layout Unlike V8 twin-turbo engines with individual downpipes per bank, the S58 inline-six uses two turbochargers feeding...