Re: Advice Requested / Spark Plugs

[Ambitious1]

I would like to ask for some advice. I am going to be putting in some new spark plugs in my 2003 naturally aspirated Mercury Marauder soon. I have been using the Denso 5326 IT20 Iridium Power Spark Plugs. However, I have been reading that many Marauder owners have switched to the NGK 4177 TR6, gapped at 0.45. I was under the impression that the Denso, being Iridium would be better? Would a NGK Iridium spark plug be best, like the NGK TR6IX? Would I need a tune if I switch to the NGK 4177 TR6 since it is "one heat range colder"? Cost aside, which spark plug would be best in terms of performance? Thank you in advance.

[fastblackmerc]

I use either NGK or Autolite plugs. If you go with a colder plug it won't buy you anything unless you have a tune that takes advantage of the colder plug... ie... more timing.

I have a Marty tune, use colder plugs and change them once a year, regardless of the mileage.

[justbob]

Honestly, unless it’s a small high performing 2 stroke engine on like a dirt bike, or even a weed whacker for that matter, I’ve never noticed any change whatsoever in one plug to the next in all the cars I’ve ever owned. Not in drivability or longevity, only the price. I’ve seen countless plugs with well over 100,000 miles that look and perform flawlessly. Now on a boosted car I’d yank them yearly just to read them, re set the gap, and quite often reinstall.

Just my opinion.


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[blazen71]

I prefer copper plugs and replace yearly