Iridium vs Ruthenium spark plugs

I have a 2012 Lexus IS350. OE plugs are Denso long life iridium's that have a triple ground configuration. Manual says to change every 60k miles. I did mine at 100k and the idle immediately changed from noticably rough through the steering wheel to butter smooth with the fresh NGK Rutheniums. Fuel economy got a healthy 1 to 2 mpg bump even with more aggressive driving.

I got about 15k on the plugs now. No issues. The Rutheniums are supposed to be harder and therefore more durable than Iridium's. I guess we'll see closer to 60k. Maybe these will be able to last longer than 60k because Ruthenium is harder than Iridium??
 
Now that NGK specs the Ruthenium HX PSPE #92400 in the correct gap for my car... I ordered them a while back and installed them.

I have had the NGK Iridium IX, and after 20,000 miles, the mpg always got bad. Maybe these will last the factory interval of 60,000 miles.
 
Originally Posted by slacktide_bitog
They know you'll have to pull the head anyway to do the head gaskets
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See that's the internet blowing things out of proportion as to how bad an issue really was... I've owned 6 Subarus (two currently) with somewhere around 500k total mileage under my use, and never had any issues with the HGs. One of them (Tribeca) was a 3.6 so not affected, but the other 5 were all the supposedly prone years: 2001, 2004, 2005, 2007, 2009. I have no qualms buying another EJ25 since between the SCC and the revised MLS gaskets put into circulation since somewhere in the 2007-2008 range have shown a majority of maintained engines have little issue. Sure, there was a campaign to fix the HGs which probably was needed due to a faulty initial design, but plenty have lived long happy lives.

The problems really seem to crop up on cars that have neglected cooling systems (spent coolant) and/or don't use SCC when the coolant is changed.
Yep- internet hysteria. One guy posts an opinion, 10000 internet experts repost it and now its a huge "issue". Happens a lot and clever parts purveyors exploit with "fixes" for non existent problem.
 
You can get 100k miles out of platinum plugs so I don't see the need to spend more for the "Ruth" plugs unless they were specifically spec'd by the auto maker.

I've only used copper, platinum, double platinums and iridiums plugs (as spec'd) so far in my lifetime.
 
The location of the spark on the Rutheniums does not look like it is the same exact location as the Iridiums. It is shifted away from the ground side by the length of the platinum ground electrode on the DFE designs.

How could this affect the way the engine runs?
 
The location of the spark on the Rutheniums does not look like it is the same exact location as the Iridiums. It is shifted away from the ground side by the length of the platinum ground electrode on the DFE designs.

How could this affect the way the engine runs?
I don't know, but with GDI engines I would not be wanting to experiment. The Laser Iridium or equivalent OE plug are all I would use. Some of these modern engines are pretty picky and a lot of BMW N54/N55/S55 guys try to "upgrade" their plugs and end up with worse results.
 
I don't know, but with GDI engines I would not be wanting to experiment. The Laser Iridium or equivalent OE plug are all I would use. Some of these modern engines are pretty picky and a lot of BMW N54/N55/S55 guys try to "upgrade" their plugs and end up with worse results.

I have a 2.4L I4 naturally aspirated engine. Been using standard plugs up until now, but was researching maybe switching to something super-long life like the Laser Iridiums or Rutheniums which is how I found this thread. I don't care about performance, just want to maintain current performance. I wouldn't mind a very long change interval though.
 
Iridium is already good for 100k, but the ruthenium is definitely worth it on cars where it's hard to do them on. Almost any transverse V6/V8, 4th gen Camaro/Firebird, Aerostar, Subarus, etc.

For cars where it's easy to do them, no need to waste the extra money on the ruthenium
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in long run ruthenium pays off.
 
Almost 5 years have gone by since the OP started this thread. In those 5 years I have not heard any negative news about Ruthenium plugs. AFAIK, they are still considered state of the art and are absolutely good for 100,000 miles. Most people will not have to pull a set out of an engine.
I did- but it was a non stock engine- I like my IX.
 
Ifaik, Ruthenium plugs are a bit better in ignitebility while maintain other qualities iridium plugs sport.
Change in design where there are two protruding tips helps with ignition yet little more.
I don't see any downsides in using Ruthenium plugs, running them in Forte and daughter's Acura, would in Sportage too if they had one for the engine.
 
I use Denso twin tip Iridiums. That's what came in the car OE. No waste spark. If it only has on special tip it's just cheaper to make.
 
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