Iridium Spark Plugs
LEONGSTER said:
Indeed good advice Roger. I used copperslip, just a tiny dab. When I first pulled mine they were the factory fitted ones I believe.
Do the NGK iridiums really make a difference? I have used Bosch platinum plugs with good results, but the effects are only temporary as the platinum seemed to act as a catalyst for better combustion but performance fell off quickly with use...
Since you pull your plugs time to time, have you tried Indexing them for more consistent performance between cylinders.
In a lot of my previous vehicles I have used the Bosch Platinum as well and always found them quite satisfactory.
Heard some good stuff about the Iridiums and decided to give them a try in the X-T.
Our Nissan dealers list 6 different plugs that are used in the QR25DE engine - in different Nissan vehicles. Here's a list (none of them are Iridium):
LZFR4AQP
LZFR5AQP
LZFR6AQP
LFR4A-11
LRF5A-11 (this is the OEM plug in the X-Trail)
LRF6A-11
My understanding is that these are really only 2 type of plugs, with the 4/5/6 numbers changing the heat range/temperature.
There is a conflict between my research on service life and that which the dealer states.
Info from the Internet suggests that a platinum plug, with a 0.8 mm diameter will give a service life expectancy of 100,000 kms.
The platinum plugs are touted to give better "ignitability" over a nickel alloy or nickel alloy V-Grove by virtue of their smaller diameter centre electrode.
The Iridium (non IX) are touted to give a service life expectancy of 160,000 kms., with the same level of ignitability as the Platinum.
The Iridium IX plug has a 0.6 mm diameter centre electrode and is "advertised" to give even greater "ignitability" over the other 2. However, their life expectancy is only rated at 60,000 kms.
I have used the Iridium IX now for about 30,000K in total (same set in 2 X-Trails). I looked for any "differences" when I first did the change over. It "seems" to me that the X-T would fire quicker (start), idle better (around 750 rpm) and "seemed" more responsive. But that is an unscientific and perhaps somewhat subjective assessment.
When I change or check the plugs, I have always replaced them in the same cylinder location. BTW, last time I looked at the plugs they were in "like-new" condition.
The OEM plugs from the dealer would cost me $6.83 Cdn. each. I got the Iridium IX from Auto Parts Warehouse in Garden Grove, CA (USA) delivered to my door for $8.69 Cdn. each.
For the price difference, limited amount of time required to do the change and the "potential" of more "fire-in-the-hole" I figured it was worthy of a try.
BTW - I did reset the ECU after the change over.
Hope this answers your questions and may be of some help to other members as well.
Cheers = Roger