IRIDIUM's ??

Tweety · Post by **Tweety** » Sun Feb 03, 2013 2:19 pm

I've has NGK iridium plugs in my Supercharged ea81 now for about 12,000kms. These have a preset permanent gap of 44 thou ".

When I first put them in I felt there was an increase in performance. However today I replaced them with the same relatively new stock NGK plugs (gap 38 thou".) Seems to em the performance overall is now better. Smoother and revs out noticably better. Maybe low down in the rev range it isnt as good.

Anyone know any more about the benefits? Maybe the extra gap has something to do with this ?

Post by **TOONGA** » Sun Feb 03, 2013 3:13 pm

NGK iridium plugs with a gap of 44 thou are for fuel injected late model cars as I understand it.

Stock NGK with a gap of 38 thou are used in small carby motors.

TOONGA

steptoe · Post by **steptoe** » Sun Feb 03, 2013 6:26 pm

Time to upgrade the sparks to handle the iridiums for a bit more than 12,000km ??

Have you been to NGK's website - some great info, maybe even an email to their techies ?

Wre the riridiums compared to new plugs just coming out of it back then or compared to crappy old ones ?

tambox · Post by **tambox** » Sun Feb 03, 2013 7:31 pm

Ive been running Iridiums in my bikes for years, I could not get more than about 10-12 ,000km for one bike and 4-5000 out of another, before they had problems, I replaced them with new Iridiums and the power/smoothness was back again.

I would get poor low down smoothness,slight miss under low revs load/idle.
At high revs they were ok.

They are better than standard plugs for power/smoothenss and economy, when they work properly.

Tweety · Post by **Tweety** » Mon Feb 04, 2013 7:05 pm

the old stock plugs had only done 4000 kms and were running fine. Think I'll stick to them too. Just overall seems smoother revving. will read the web site though Steppy. Thankx Toonga/Tambox

RSR 555 · Post by **RSR 555** » Tue Feb 12, 2013 3:31 pm

Remember any forced inducted engine will require cooler type plugs and Platnium or Iridium plugs are highly recommend. Also need to sure the gap isn't too big as forced engines have a lot more compressed air in the cylinder and make it hard for the spark to "jump".

Finding the correct gap size can be tricky, as this depends on boost pressures and ignition system. I'd set at 75% of standard and try to tune using the lowest grade fuel and under heavy load.