GENUINE MAZDA OEM Spark Plugs for Mazda RX8 (Series 1 & 2, 2003-2012)

Part details

RX8 spark plugs from Mazda are the factory-correct ignition service solution for the Renesis rotary engine. Each set includes two RE7C-L leading plugs and two RE9B-T trailing plugs, matching the engine's dual-position ignition layout exactly. These are sourced direct from Mazda Japan and feature a patented electrode design and gap specification. Worn or incorrect plugs are a leading cause of hard cold starts, rough idle and misfires on the Renesis. Genuine RX8 Spark Plugs Set Features The RE7C-L and RE9B-T pairing matches the Renesis leading and trailing ignition positions exactly. Neither position is compromised by an incorrect substitute. Mazda's patented tip geometry and gap specification delivers a factory-correct heat range calibrated for the Renesis combustion cycle, not a universal aftermarket approximation. Each plug shell carries a nickel-plated finish over a precision-formed body, with a ceramic insulator and interference suppression resistor built in. Replacing all four plugs together removes age and condition as variables. This gives you a known ignition baseline when diagnosing starting or idle behaviour. Finally, sourcing as a complete OEM set means both plug types arrive together, making your Renesis plug service straightforward and eliminating the risk of ordering mismatched plugs. For RX8 enthusiasts, fresh plugs make the biggest difference on the first cold start of the day. The Renesis depends on both leading and trailing positions firing correctly. Fitting a genuine set restores that balance in a way an aged or incorrect set simply cannot. A complete ignition refresh pairs naturally with a healthy fuelling system. Pair these RX8 spark plugs with a GENUINE MAZDA OEM MAF Sensor to keep air-metering accurate. A GENUINE MAZDA OEM Fuel Pump is worth considering if the fuelling side is overdue. Genuine parts for the RX8 are becoming progressively harder to source, so keeping a spare set alongside your service schedule is worthwhile. For further Mazda ownership and service information, visit Mazda Australia .

Listed fitment

Model

Series 1 (2003-2008)

Model

Series 2 (2009-2012)

Part information

SKU

OM-SPL-S1S2

Brand

GENUINE MAZDA OEM

Which spark plugs does the Renesis rotary engine use, and are the leading and trailing plugs different?

Yes, the Renesis uses two distinct plug types. The leading position uses RE7C-L plugs and the trailing position uses RE9B-T plugs. They are not interchangeable - fitting the wrong type to either position will compromise ignition performance, so a matched OEM set is the safest approach.

How many spark plugs does an RX8 have?

The RX8 Renesis rotary engine has four spark plugs in total - two RE7C-L leading plugs and two RE9B-T trailing plugs. The genuine Mazda OEM set includes all four, covering both ignition positions across the two rotor housings.

Will worn spark plugs cause hard cold starts and rough idle on an RX8?

Yes. Worn or incorrect spark plugs are one of the most common root causes of hard cold starts, rough idle and misfires on the RX8. The Renesis ignition system depends on both leading and trailing positions firing correctly, so aged plugs in either position can disrupt the entire combustion cycle.

Are these spark plugs genuine Mazda OEM parts, or aftermarket alternatives?

These are genuine Mazda OEM spark plugs, not aftermarket substitutes. They carry factory-correct heat range and electrode design calibrated specifically for the Renesis combustion cycle, rather than a universal aftermarket approximation.

Do these plugs fit both Series 1 and Series 2 RX8 models?

Yes. The genuine Mazda OEM spark plug set is correct for all RX8 models across both Series 1 (2003-2008) and Series 2 (2009-2012).

How often should RX8 spark plugs be replaced?

The Renesis rotary engine is harder on spark plugs than a conventional piston engine, so plugs typically need replacing more frequently. Fitting a complete set of four at each service interval removes plug age and condition as variables when diagnosing any starting or idle issues.

Should I replace all four RX8 spark plugs at the same time?

Yes. Replacing all four plugs together establishes a known ignition baseline, which makes diagnosing any future starting or running issues significantly more straightforward. Mixing old and new plugs, or plugs of different conditions, can make fault-finding more difficult.

What other parts should I replace alongside the spark plugs for a full ignition service?

A fresh set of spark plugs works best when the rest of the ignition and fuelling system is in good condition. If you are addressing hard starts or rough running, it is worth checking the MAF sensor and fuel pump at the same time, as faults in either can mask or replicate ignition-related symptoms.