A 400 cell catalytic converter packs a higher cell density into the same housing than a 100 or 200 cell unit, giving exhaust gas more surface area to react with before it exits the tailpipe. That makes it the go-to choice when emissions compliance is the priority, such as roadworthy inspections or replacing a factory-fitted cat on a later-model petrol vehicle. It runs slightly more restrictive than a low-cell-count unit, so it suits daily drivers and compliance-focused rebuilds rather than all-out performance builds. Browse our full range of catalytic converters, or compare against our 100 cell catalytic converters if flow matters more than emissions coverage for your application.

What does "400 cell" mean on a catalytic converter?

Cell count refers to the number of small honeycomb cells per square inch inside the converter. A 400 cell unit has more, smaller cells than a 100 or 200 cell unit, giving it more surface area for emissions conversion but slightly more back pressure.

Is a 400 cell catalytic converter legal for a roadworthy or pink slip in Australia?

Generally yes, as 400 cell converters are favoured for compliance-focused replacements. Requirements vary by state, so it's worth checking with your inspecting mechanic if you're unsure.

400 cell vs 100 cell catalytic converter — which is better?

A 100 cell converter flows more freely and suits performance-focused builds, while a 400 cell converter prioritises emissions compliance. The right choice depends on whether your vehicle needs to meet strict roadworthy or ADR requirements.

What size catalytic converter do I need?

Measure the inside diameter of your existing exhaust pipe at the cat location, or check compatibility by vehicle model. Contact our team if you're unsure of the correct diameter or bolt pattern.