Mazda RX-8 Catalytic Converter Replacement Parts

Yes, every Mazda RX-8 sold in the UK was fitted with a catalytic converter as standard. The RX-8 uses a 1.3-litre Wankel rotary engine (engine code 13B-MSP) across all variants, and because it is a petrol engine it relies on a catalytic converter to meet emissions regulations. There is no diesel or hybrid variant of the RX-8, so all examples have a cat.

The RX-8 ran from 2003 to 2012 in the UK, with a significant facelift arriving for the 2009 model year that brought emissions and engine management changes alongside a power increase on the higher-output variant. Because of those emissions-era changes around 2009, a cat from a pre-facelift car may not be a straight swap onto a post-facelift car and could affect your MOT emissions result. Name the exact year boundary when speaking to the breaker and ask them to confirm the part matches your specific registration before purchasing.

Yes, this is worth checking — the RX-8 was offered in two power outputs, often referred to as the 192 and 231 (later revised) variants, which had different engine maps and exhaust configurations. The exhaust system, including the catalytic converter, can differ between these outputs even on cars of the same year, so you cannot assume they are interchangeable. Always tell the breaker your exact power variant and registration so they can confirm the correct cat.

No — trim level alone does not affect catalytic converter fitment on the RX-8. Trims such as the standard, Sport, and PZ do not change the engine or exhaust specification in a way that alters the cat itself. What matters is the engine output variant and the model year, so focus on those details when sourcing from a breaker.

A used catalytic converter from the correct variant and era should allow the car to pass MOT emissions if it is in good working order, but the RX-8's rotary engine is known for running slightly rich and can damage or clog a cat over time, so condition matters greatly. Make sure the breaker can confirm the cat came from a car matching your power output and model year, particularly if your car is a post-2009 facelift example where emissions calibration changed. Fitting a cat from the wrong era or a worn-out one is a common MOT failure point on these cars, so confirm specifics with the breaker against your registration before buying.

The 2009 facelift is a known boundary on the RX-8 where engine management and emissions-related components were updated, which means cats from either side of that cut-off may not be directly interchangeable. Whether a specific unit will physically fit and meet your car's emissions requirements is strong confirm-with-breaker territory — give the breaker your full registration and ask them to cross-reference the part against your exact build. Never assume a visually similar cat from the other era will pass your MOT emissions test without that confirmation.