Worth the $$$ - NGK Iridium Spark Plugs?

[JimX]

Maybe my feeler gauges are wrong, but I couldn't fit the 0.8 measurement into the gap. I decided not to force it due to the sensitive iridium, so I tried 0.7 and it fit in nicely without any slack.

[ScarifieR]

nup no difference between the 2 plugs (plat and irid)

i gapped the iridiums at .9mm

they come 1.1 standard if u have the plugs with 11 at the end

they run fine

[Zensoku]

After reading all of these posts, Lunatic Dancer appears to be the most informed, and is pretty much spot on with what he is saying.

I hate to be thrown into the basket as being the "self confessed know-it-all" but where i work every day, i am faced with making recommendations on spark plugs to normal every day drivers and enthusiasts alike, i am bored and have got time to kill, so here goes...

1. You can put in NGK "R" copper plugs, just don't expect a very long life, as the electrode isn't as fine as the Iridium IX plugs in particular, and generally wear and foul very quickly. Depending on the condition of your engine, and how you drive your car (ie: hard all of the time?) expect in between 10,000km-15,000km life.

2. NGK Platinum plugs are the "old school" plugs and have been around for over 15 years now. they basically addressed the problem of copper plugs generally fouling and wearing out due to their platinum coating. (expect up to 100,000km in a standard, well maintained and tuned engine)

3. NGK Iridiums are the newer technology plugs, they come in IX, Iriway and Iritop variants. Most commonly sold are the Iridium IX's due to their long life (around 150,000km, again in a well maintained and tuned engine) and ability to provide a sharper, stronger spark due to their ultra fine tip on the electrode which requires less voltage to create a good spark, hence, make slightly more power and stable combustion. Also, in their design nature, they "self clean" the carbon buildup around the electrodes to avoid fouling.

4. They can be bought pre-gapped at 0.8mm and 1.1mm as the most popular preset gaps. the dash eleven on the end of the part number designates a 1.1mm gap. no dash and a number on the end defaults to a 0.8mm gap.

5. Going to a colder heat range (going up in the number) generally allows for more power, less economy. this alters the length of the combustion process. Going to a hotter heat ranger is required when you need a hotter combustion to control oil fouling the plugs in tired engine which uses oil (rings aren't sealing well, and getting a little bit of blow-by)

6. Iriway and Iritop NGK's have a lower life than the IX's and are meant for race use. Note that all of the Japanese name brands like HKS, TRUST, etc have NGK "rebadge" these plugs as their own...

7. Some engines that have higher boost than standard suffer from misfires, so a slightly smaller gap helps. (ie: Down from 1.1mm to around 0.7mm-0.8mm usually)

8. Regap platinum and Iridium plugs at your own risk, as you can scratch the coating off both the electrodes and the grounds.

9. NGK V-Grooves were introduced for economy reasons and are still the same as regular coppers, but with a "V" cut into the end of the electrode tip to allow a btter way for the spark to jump across and ground itself.

Make up your own decision with plugs, taking into consideration, cost, life expectancy, your intended driving style. (track, drag, street)

From memory:

NGK "R" copper: BCPR6ES-11

NGK Platinum: PFR6A-11

NGK Iridium IX: BCPR6EIX-11

remember to remove the -11 if you want the default 0.8mm gap instead. and the IX's are now generally cheaper than the platinums now. they RRP at $18.50 each AUD.

This will be my last post on plugs, as i have posted before on this topic numerous times, hope that this is all of some help and consideration...

Zen..

[ricknismo]

So what makes iritops twice the price of iridiums??

[GR33DY]

i got HKS spark plugs in my SR.. massive difference over what ever was in it before... much smoother but were $25 each =( lol

Rob