Spark plugs

[Ianmc]

Thinking of replacing spark plugs and am considering NGK.
ECP list NGK Type Iridium "earthed electrode" at £13.99 and NGK Iridium Type Laser Line "middle electrode" at £25.49 each.
A significant difference in price, are the more expensive plugs worth while?
Grateful for informed views,
Cheers,
Ian

 

[Zephyr]

While I had the Z, I tested both types with my scan tool.
plugged them in and took readings from the “smooth running values” of the engine as also the correction of the afm and spark advance.
the laser line had higher readings (smooth from 0.14-0.25 in contrary to 0.05 to 0.1 that the iridium ones had and also it seemed that the ecu was trying to compensate adding air (+1) and retard the engine.
my very wise guru friends told me that this behaviour shows a more sufficient spark but I kept the iridium ones as the engine seemed to be happier with these.
FYI my Skyactive G 2.0 engine in the MX5 has Laser ones and book says they are good for 100.000 km whereas the 1.5 has Iridium and they need to be replaced ever 20.000 km.
So maybe long life is another variable to consider.

 

[Ianmc]

Many thanks @Zephyr , that seems useful research. As both types are Iridium, would we conclude that the Laser Line should offer better performance and could last significantly longer? I wonder whether the performance gain would be noticeable and worth the additional outlay?

 

[Zephyr]

I am not a mechanic and unfortunately am a software engineer (not the useful ones) but from what I understand since the engine asks for more air, there has to be a better combustion in the chamber.
on the other hand the ecu tried to retard the ignition (only by little but still some) so I understand the Laser lines do their job better and from what the Mazda manual says last longer.
if you decide to change them, reading the values with your scanner before and after will probably verify my “research” and maybe help others.

 

[elky]

Does anyone have any similar results/comparison for M54B30?