Wagner Tuning Monolith 300CPSI EU6 Ø150×120

Wagner Tuning Monolith 300CPSI EU6 Catalyst – Ø150x120mm

The Wagner Tuning Monolith 300CPSI is a universal high-flow catalyst module, designed to be welded into a custom or modified exhaust system. With a 150mm diameter and 120mm length, it suits a wide range of performance builds where a standard catalytic converter is too restrictive for the power being produced.

At its core is a 300 cells per square inch (CPSI) substrate finished with a EURO 6 compliant coating. Compared to a standard road catalyst (typically 400 or 600 CPSI), the lower cell density allows exhaust gases to flow through more freely, reducing backpressure and helping the engine breathe better. The result is improved exhaust efficiency, which can support modest power gains and a sharper throttle response, particularly on tuned and turbocharged engines.

Key Features

• 300 CPSI metallic substrate for a strong balance between flow and emissions control
• High-quality EURO 6 catalyst coating
• 150mm outer diameter, 120mm overall length
• Universal weld-in design for custom downpipes, mid-pipes and full exhaust fabrication
• Helps reduce exhaust backpressure and supports higher gas flow on tuned engines

What It Does and Why It Matters

A catalyst’s job is to clean up harmful gases before they leave the exhaust. Higher-cell catalysts clean more thoroughly but restrict flow. Lower-cell motorsport catalysts like this 300 CPSI unit are designed for performance applications where reducing restriction is the priority, while still providing a meaningful reduction in emissions thanks to the EU6 coating. This makes it a sensible choice for tuners who want better flow than a 200 CPSI sport cat, but more emissions control than a decat or straight pipe.

Typical Applications

Because this is a universal weld-in module, it can be used in fabricated downpipes, sports exhaust systems and bespoke motorsport builds across a wide range of petrol vehicles. Use the vehicle lookup or check the Vehicle Fitment tab to confirm suitability, or measure your existing exhaust to ensure the 150mm diameter and 120mm length will work in your build.

Specifications

Important: This catalyst is intended exclusively for motorsport vehicles used outside of public road regulations (StVZO). By purchasing, you confirm that this item will not be fitted to a vehicle used on public roads. Installation should be carried out by a qualified exhaust fabricator to ensure correct welding, alignment and sensor placement.