Fresh OEM leading and trailing plugs restore correct Renesis ignition, addressing hard starts, rough idle and overdue plug services on all RX8 models.
Independent reviews of this product gathered from other stores and owner communities.
If you ever do replace them, go OEM only. As I understand it, the plug is actually part of a feed-back system for the ignition stuff. I am unsure if Mazda tweaked the plugs from what you can buy off the shelf generic, or not, but I don't want to play that game.
I now definitely would use OEM PE5R-18-110 plugs although they cost a lot more than NGK's.
I went ahead and replaced them on our 2014 Grand Touring AWD after almost 5 years and 60k miles. I know the manual says 75k miles but I figure it was time given the high compression ratio SkyActiv engines and the lots of stop and go seen by this car (my spouse's hour long city commute). I got the Mazda OEM plugs (PE5R-18-110) despite their high cost, given the experience of others on this forum. Very straightforward job: remove the cover, remove the bolts holding the ignition coils, unplug connector for each coil, and remove and replace plugs. After seeing them I'm glad I replaced them.
$290
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.
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.
Independent reviews of this product gathered from other stores and owner communities.
If you ever do replace them, go OEM only. As I understand it, the plug is actually part of a feed-back system for the ignition stuff. I am unsure if Mazda tweaked the plugs from what you can buy off the shelf generic, or not, but I don't want to play that game.
I now definitely would use OEM PE5R-18-110 plugs although they cost a lot more than NGK's.
I went ahead and replaced them on our 2014 Grand Touring AWD after almost 5 years and 60k miles. I know the manual says 75k miles but I figure it was time given the high compression ratio SkyActiv engines and the lots of stop and go seen by this car (my spouse's hour long city commute). I got the Mazda OEM plugs (PE5R-18-110) despite their high cost, given the experience of others on this forum. Very straightforward job: remove the cover, remove the bolts holding the ignition coils, unplug connector for each coil, and remove and replace plugs. After seeing them I'm glad I replaced them.
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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.
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.
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.
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.
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).
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.
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.
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.
