Spark Plugs: Copper vs Iridium vs Platinum FF#32

[Sommerfeldt]

OE plugs may not be the best possible 'configuration' that can be achieved, but reconfiguring properly goes beyond simply throwing a different plug under there. With something as 'big' as the spark plugs you need to take the car to a tuner to have the ECU software/maps customized - else at best you simply won't likely gain the full potential advantage of using those alternate plugs, or at worst you risk engine and/or catalyst damage.

I use Denso Iridium IK20. They’re supposed to come gapped at .044, but didn’t - properly gapped, they’ve been excellent, though. I haven’t got a planned change interval - I’m going to pull them when I do the timing belt in a couple of thousand miles, and if they look good, they go back in. They should last a pretty while.

As to remapping for spark plugs, I don’t think that’s accurate at all. Spark plugs aren’t “big” - they don’t facilitate more airflow, more injected fuel, higher pressures or alter timing. Spark plugs produce spark. With better plugs, you can get a more reliable burn at the correct time, and better power that way, essentially just giving the engine and ECU what they’re expecting will happen, when it’s expected.

If you add fuel or air, need a different load request curve or TCV duty cycle for boost build or onset, that’s a remap. Spark plugs not so much.

- S

[KLR142]

You don't need anything re-tuned to use different spark plugs and you won't risk engine or catalyst damage if they have the right gap, measurements and heat range...

[mrbrian200]

You don't need anything re-tuned to use different spark plugs and you won't risk engine or catalyst damage if they have the right gap, measurements and heat range...

I might have agreed with that prior to ~y2k, particularly on NA engines dating to before modern computerized ECU fuel delivery/spark timing control, and early ECU designs that were by modern standards still pretty 'sloppy'. Not now though.

[KLR142]

That's ok, you don't have to agree. I'm just telling it like it is.

[precopster]

You're not the first to report this.

Just wondering what brand of coil packs you have. Are they all Bosch or is there an aftermarket one or two thrown in there?

[mrigmo]

See I agree with you about this aspect. Everyone is arguing that the plugs don't matter for fuel and air tuning. That may be true, but your ignition coils are tuned to produce a certain voltage for an exact duration and your ECU is assuming things down stream to be at a certain spec. Some components are designed to be tuned by the ECU, others are designed at exact specs that are assumed in all the tables that the calculations the ECU makes are based off of. If there isn't a sensor or a way to go in and alter that data then every calculation it makes will be wrong. A plug running really hot can cause the gas to pre-ignite before the piston reaches the apex of it's climb. It can cause hot spots, burning oil, metal fatigue etc. The impedance of the plug can cause arcing in the wire harness or even across the terminals in the ECU, if jumping that gap is easier then jumping the gap in the plug it will do it. Many things the ECU senses and adjusts dynamically while the car is running without any need to have the car tuned. If you provide more air and more fuel most often the computer will know what to do.