BMW F8x M3 / M4 Equal Length Valved Sport Exhaust System

BMW F8X M3/M4 Valved Cat-Back Exhaust System Equal-Length 2.75" Mid-Section with H-Pipe and 3.5" Axle-Back (T304 Stainless Steel or Grade 5 Titanium) Overview The S55 engine powering the BMW F8X M3 and M4 is a performance masterpiece, but its stock exhaust note has long been criticized for excessive rasp and a lack of tonal depth. The Valvetronic Designs Equal-Length Valved Cat-Back is the definitive solution—eliminating the factory harshness and unlocking the rich, balanced sound the S55 was always capable of producing. This system features a 2.75-inch equal-length mid-section with an H-pipe feeding into a 3.5-inch axle-back. The equal-length design smooths the exhaust tone across the rev range while preserving the aggressive character owners love. With valves open, gases exit freely from the passenger-side tips for maximum volume and performance. With valves closed, flow is routed through our quad-chamber muffler to the driver-side tips for a quieter, more refined note—ideal for daily driving. No cutting or welding is required—this is a true direct bolt-on system designed to mount to factory points. Why It Works Equal-Length Mid-Section: Balances pulses for a cleaner, smoother tone without losing aggression. H-Pipe Design: Improves scavenging for a fuller, more refined sound. Dual-Mode Operation: Raw and loud (open) or subdued and civilized (closed). Sound & Control Valves Open: Aggressive, free-breathing tone with reduced rasp and improved high-rpm clarity. Valves Closed: Stock-like sound levels for stealthy driving. Electronic Valve Control: Includes standalone controller; OEM integration available. Construction & Options Materials: T304 stainless steel or Grade 5 titanium. Weight Savings: –21.7 lb (Stainless) / –49.2 lb (Titanium) vs. OEM. Craftsmanship: Precision TIG welds and fully mandrel-bent tubing for maximum flow. Tips: Multiple premium finish options to complement your M3 or M4. Fitment 2015–2018 BMW M3 (F80) 2015–2020 BMW M4 Coupe (F82) 2015–2020 BMW M4 Convertible (F83) Installation Notes Direct bolt-on; no cutting or welding required. 100% reversible—return to stock at any time. Note for S55 Owners: On free-flow/race downpipes, “2k rpm rasp” may be present during low-rpm shifts. For the most refined tone, we recommend high-flow (200 cell) catalytic converters. What’s Included 2.75" equal-length H-pipe mid-section 3.5" axle-back with quad-chamber muffler Electronic valve system with controller (OEM integration optional) All necessary clamps and hardware Specifications Mid-Section Diameter: 2.75" equal-length with H-pipe Axle-Back Diameter: 3.5" Material: T304 stainless steel or Grade 5 titanium Valves: Electronic, rapid open/close Weight Savings: –21.7 lb (Stainless) / –49.2 lb (Titanium) vs. OEM Design: Quad-chamber muffler for refined closed-valve tone