Rx8: Changing the spark plugs

Changing the spark plugs on the Rx8 is an important part of your regular maintenance (around every 30.000km/18.000miles).

If you drive in a more adventurous way, like me, or daily your Rx8, well, you want to change them yearly even. Why? Let me explain.

Spark plugs put out an electrical spark and ignite the fuel/air mixture in your combustion chamber, where pressure then builds up and forces your rotor to move. Basically, it is what helps fire up your engine. Bad or old spark plugs will lead to a lot of inconvenient problems for your car:

• loss of acceleration power

• bad fuel economy

• rough idling and misfiring

• a hard to start engine…

So yes, better change them on time before you regret it later.

NGK Laser Iridium Racing Spark Plugs

After using the OEM Mazda spark plugs for years I decided to try out the NGK Laser Iridium Racing Spark Plugs. People in the Rx8 community have been recommending them a lot and so does Charles from Black Halo Racing, my main reference for upgrades to my girl. I ordered them from the internet and of course I was excited to see if they made a big difference! Read on to learn which ones I prefer: NGK or OEM?

Changing the spark plugs on the Rx8 is rather easy.

First you put the car up (I always recommend working on a lift) and turn the steering wheel all the way to the right to free up your front left wheel hub. The plugs themselves are located at the drivers’ side, right behind a little plastic flap you simply unhinge. You will recognize them by the wiring that sticks out of them. Gently take off the wiring by unplugging the caps and start screwing them off!

Advice 1: Please make sure to change one plug at a time, so you don‘t mix trail and lead plugs up. The plugs themselves are marked T for trail or L for lead and have different lengths/forms, so identifying them is quite simple.

Advice 2: It is also strongly recommended to use a specialized spark plug wrench to not damage the plugs during the install.

If you are brave like me and have tiny delicate asian hands, you can kinda do without.

I unscrewed the old ones with a classic wrench (hulk must have screwed them in because they were stuckkk) and used the torque wrench to screw the new ones back in.

Afterwards put the wiring back and tada; you are done!

Moving on to the fun part: is there a difference to the standard OEM plugs? Well, hell yes, there is! My baby starts up almost instantly, and she accelerates even better than before. I felt it most while accelerating in lower RPM and higher gears on the highway: you feel the cars’ pull immediately with these new plugs. People did not exaggerate, and I love it!

Now a few last words of caution from someone who did her research: when choosing your Rx8 spark plugs make sure you consider your daily driving style!

I use the NGK Laser Iridium sparks because although I love to drive my babe in high RPM, I only do it in shorter bursts and, I daily drive her around 3-4k RPM. So the medium heat range from the NGK is perfectly fine. If you choose a plug with a very high heat range (e.g. Denso Iridium Racing) and you don‘t drive accordingly in constant high RPM, your plugs will quickly foul, and you‘ll find yourself back with the issues I mentioned at the beginning.

Thank you for reading this far and if you have any questions or comments, feel free to contact me!