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The MagnaFlow 51578 is a direct-fit replacement catalytic converter for specific cars, built from stainless steel and designed to bolt onto the factory exhaust flanges without cutting or welding. It uses a ceramic substrate sized to the vehicle's federal emissions requirements, so it is a stock-style repair part rather than a performance upgrade. It suits owners replacing a failed or rusted converter on a federally certified car who want a fit that matches the original. Compared with universal converters, it costs more but avoids fabrication; compared with OEM parts, it is a common aftermarket alternative, though it is not legal for California or other CARB states.
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Lowest price we've seen: $564.12 on Nov 9 at TWIST. Tracked across 4 stores since Nov 9.
Owners of direct-fit MagnaFlow converters generally report a clean bolt-on fit and quiet, stock-like operation after replacing a failed unit. Complaints center on fitment on some vehicles and on the part not being legal in CARB states.
The Magnaflow Direct-Fit Federal Catalytic Converter 51578 is a bolt-on catalytic converter for cars. It is designed to meet exact original equipment specifications and has a federal emissions compliant design.
The case is stainless steel and the substrate is ceramic. Magnaflow uses ceramic and metallic substrates with different cell density and wall thickness combinations to meet vehicle-specific requirements. The converter is formulated for gas and diesel applications.
It is a direct-fit design intended for easy bolt-on installation by a professional installer. The inlet is a 2-1/2 inch 3-bolt flange, and the outlet is a 2-1/2 inch bolt-on connection.
