Catalytic Converters

Which catalytic converter does your project need – a model developed specifically for your car, or a universal unit you adapt to the pipework yourself? This category brings together catalytic converters for you who need to replace a faulty original or build a new exhaust system.

What a catalytic converter does in the exhaust

The catalytic converter converts part of the harmful substances in the exhaust gas, typically carbon monoxide, unburned hydrocarbons and nitrogen oxides, into less harmful compounds. It sits after the exhaust manifold or headers, and its construction affects both emissions and back pressure. A clogged or damaged catalytic converter can cause loss of performance, fault codes and problems at the vehicle inspection.

How to choose a catalytic converter

The choice depends on more factors than just the pipe diameter:

• Fitment: direct-fit catalytic converters are made for specific models, e.g. Subaru WRX 2.0L, and typically use the original mounting points.
• Universal solution: universal catalytic converters are available in different diameters and lengths, e.g. 2 and 3 inches, and normally need to be welded in.
• Cell density: stated e.g. as 400 cells, it affects the balance between cleaning and flow. The right choice depends on the engine, power goals and the other exhaust components.

Installation, inspection and brands

Whether a catalytic converter is legal for road use depends on the product and the car, and approval, e.g. E-mark, must be checked for the specific part number before you install it. Lambda sensors typically need to be positioned correctly in relation to the catalytic converter, otherwise the engine management may report faults. In this category you will find brands such as Magnaflow, Remus, HKS, aFe and Flowmaster.

Frequently asked questions

What is the difference between a direct-fit and a universal catalytic converter?

A direct-fit catalytic converter is developed for specific car models and is typically mounted in the original hangers. A universal catalytic converter is chosen based on pipe diameter and length and normally has to be adapted and welded into the exhaust.

Is the catalytic converter approved for road use and inspection?

It depends on the product and the car. Check the approval, e.g. E-mark, for the specific part number, and make sure the car still meets the emission requirements after installation.

How can I tell that the catalytic converter needs replacing?

Typical signs are rattling from loose internal parts, fault codes from the lambda sensors, loss of performance or increased emissions at inspection. The cause may also lie elsewhere, so have the fault diagnosed first.