Spark plugs for the Kizashi

[SamirD]

Some others like the NGK V-Powers are made in the USA.

That's the funny thing. The Honda and Nissan parts are just NGK v-powers, but made in Japan. And there's a huge quality difference just looking at the tolerances between a usa v-power and the dealer part.

It's crazy, but I've even seen high end Accel plugs just rebadged made in Japan Denso plugs. From what I've found, it's more important to look at the plug itself than anything else. Even Denso's made in Japan plugs available at part stores that are their equivalent to the made in usa NGKs aren't that great.

[murcod]

Exactly.

My personal preference are NGK Iridium IX. They are only several bucks and they last quite a while. There are better iridium plugs out there, but I'm just more eager to change plugs sooner so I use the IX which are rated up to 75,000 miles. I usually change them sooner. That being said, I'm using what came from the factory. My car has less than 25,000 miles.

http://www.ngksparkplugs.com/pdf/DYK_La ... m%20IX.pdf

Iridium IX are rated at only 40 to 50 thousand miles, Laser Iridium are 80 to 100 thousand miles. There's not a huge price difference between the two, but the Laser has twice the life.

The Laser Iridium is also listed as being the OE spec part.

PS: On Rockauto you're looking at US$6.83 ea (Iridium IX) vs US$9.73 ea (Laser Iridium)

[KuroNekko]

Exactly.

My personal preference are NGK Iridium IX. They are only several bucks and they last quite a while. There are better iridium plugs out there, but I'm just more eager to change plugs sooner so I use the IX which are rated up to 75,000 miles. I usually change them sooner. That being said, I'm using what came from the factory. My car has less than 25,000 miles.

http://www.ngksparkplugs.com/pdf/DYK_La ... m%20IX.pdf

Iridium IX are rated at only 40 to 50 thousand miles, Laser Iridium are 80 to 100 thousand miles. There's not a huge price difference between the two, but the Laser has twice the life.

The Laser Iridium is also listed as being the OE spec part.

PS: On Rockauto you're looking at US$6.83 ea (Iridium IX) vs US$9.73 ea (Laser Iridium)

Laser Iridiums used to be more expensive several years ago. I used to see them sold for close to $12 each. I like the IX because I like to change plugs more frequently than a long interval anyways. I always knew they had a shorter lifespan than other iridiums as they were cheaper and more geared for enthusiasts than OEM applications. I guess I got their lifespan mixed up though I used to change them out around every 50,000 miles or earlier anyways.

While getting "better" plugs hardly improves performance as in power, getting newer plugs do. By the time the Laser Iridiums have something like 60,000 miles, they are not good, but more "good enough". This is why I rather change out the plugs more frequently even if the plugs going in are not as good. After all, the condition of the plugs appear to be more important than type and technology of the plug. Yes, it costs more money, but I like this kind of thing anyways. I'm a car enthusiast as many of us here are.

I also wanted to share this with you guys: My mother sends me JDM car magazines from Japan and I often pay attention to the ads. There was an ad for a new kind of NGK plug. I have not yet found any English sites on this product. The plug is called "NGK Premium RX" and its special feature is a "ruthenium center electrode"... whatever the F that is.
Here's the translated blurb they have about it: "Adoption electrode outside + Oval shape protruding platinum and new material ruthenium center electrode formulated the world's first. It is the birth of the next generation premium plug to operate with ignition and outstanding, was extremely low fuel consumption, fouling resistance, long life, etc., the total performance."

Here's the Japanese site on it. http://www.ngk-sparkplugs.jp/products/s ... index.html

Oddly, clicking on "English" at the Japanese page merely takes you to a dumbed down site which does not cover the new Premium RX plug at all. However, there they warn you of the risks of imitation NGK plugs. I had no idea people bothered to counterfeit spark plugs. LOL.
Google translate can get you some info on the Premium RX plug from the Japanese site.
There is also some discussion on the plugs among Subaru Legacy owners here:
http://legacygt.com/forums/showthread.p ... l?t=220656
Reading them bitching about how hard it is to change the plugs on a Subaru boxer reminds me of what I don't miss on my Subarus.

Imported prices for these are ridiculous. I may see how much they cost in the JDM when I visit (hopefully in the next few months). However, I highly doubt they will make any car significantly better in terms of performance. Smoother idle and slightly better fuel economy are more likely than anything.

[SamirD]

Iridium IX are rated at only 40 to 50 thousand miles, Laser Iridium are 80 to 100 thousand miles. There's not a huge price difference between the two, but the Laser has twice the life.

The Laser Iridium is also listed as being the OE spec part.

PS: On Rockauto you're looking at US$6.83 ea (Iridium IX) vs US$9.73 ea (Laser Iridium)

Interesting. How much is the dealership list for the plugs?

[murcod]

While getting "better" plugs hardly improves performance as in power, getting newer plugs do. By the time the Laser Iridiums have something like 60,000 miles, they are not good, but more "good enough". This is why I rather change out the plugs more frequently even if the plugs going in are not as good.

Applying the same logic to the Iridium IX you'd be replacing them at 30000 miles..... and you're making a lot of assumptions regarding the spark plug life!

If they're ever not firing properly you'll quickly get engine fault codes logged as your O2 sensor readings will be going crazy from unburnt fuel exiting via the exhaust.

[bootymac]

Exactly.

My personal preference are NGK Iridium IX. They are only several bucks and they last quite a while. There are better iridium plugs out there, but I'm just more eager to change plugs sooner so I use the IX which are rated up to 75,000 miles. I usually change them sooner. That being said, I'm using what came from the factory. My car has less than 25,000 miles.

http://www.ngksparkplugs.com/pdf/DYK_La ... m%20IX.pdf

Iridium IX are rated at only 40 to 50 thousand miles, Laser Iridium are 80 to 100 thousand miles. There's not a huge price difference between the two, but the Laser has twice the life.

The Laser Iridium is also listed as being the OE spec part.

PS: On Rockauto you're looking at US$6.83 ea (Iridium IX) vs US$9.73 ea (Laser Iridium)

100% increase in lifespan while only costing 42% more. In terms of cost per distance, the Iridium IX costs $1.52 per 10000 miles while the Laser Iridums cost $1.08.

The Laser Iridium plugs are making a lot of sense

[LPSISRL]

Exactly.

My personal preference are NGK Iridium IX. They are only several bucks and they last quite a while. There are better iridium plugs out there, but I'm just more eager to change plugs sooner so I use the IX which are rated up to 75,000 miles. I usually change them sooner. That being said, I'm using what came from the factory. My car has less than 25,000 miles.

http://www.ngksparkplugs.com/pdf/DYK_La ... m%20IX.pdf

Iridium IX are rated at only 40 to 50 thousand miles, Laser Iridium are 80 to 100 thousand miles. There's not a huge price difference between the two, but the Laser has twice the life.

The Laser Iridium is also listed as being the OE spec part.

PS: On Rockauto you're looking at US$6.83 ea (Iridium IX) vs US$9.73 ea (Laser Iridium)

100% increase in lifespan while only costing 42% more. In terms of cost per distance, the Iridium IX costs $1.52 per 10000 miles while the Laser Iridums cost $1.08.

The Laser Iridium plugs are making a lot of sense

Or .000044 cents per mile.

[KuroNekko]

While getting "better" plugs hardly improves performance as in power, getting newer plugs do. By the time the Laser Iridiums have something like 60,000 miles, they are not good, but more "good enough". This is why I rather change out the plugs more frequently even if the plugs going in are not as good.

Applying the same logic to the Iridium IX you'd be replacing them at 30000 miles..... and you're making a lot of assumptions regarding the spark plug life!

If they're ever not firing properly you'll quickly get engine fault codes logged as your O2 sensor readings will be going crazy from unburnt fuel exiting via the exhaust.

Well, you are assuming that mileage and use duration has no effect on performance degradation. You are approaching it like as if 30,000 miles will affect a plug the same way as 60,000 miles. While there is some difference between the plugs, I believe that the IX will be in better shape after 30K than the Laser at 60K given the Laser went through twice the amount of miles, regardless of its better materials. Keep in mind that over time, plugs degrade at a faster rate due to building amount of wear and increased gap.

Also, spark plugs rarely suddenly fail and then cause issues that throw CELs. They typically degrade over time in a gradual process. Over time, their gap erodes and this erosion is actually what makes them less efficient in fuel economy, power, and ignition. The spark plug materials wear out, but it's the gap that's main factor.

While I agree with you all that the Laser Iridium is the better economic choice and it lasts longer, I'd rather change my plugs out more frequently to maintain optimal performance. I've been using Iridium IXs for years in at least three different cars. I've always liked them. I also note a good amount of performance restored when I change the plugs at my intervals. It it well known that plug condition matters far more than plug type. A new copper plug will be better than an old Laser Iridium plug in an engine.

I also consider inline 4 cylinders the simplest engine to change plugs on. After owning Subarus with boxer engines and working on my ex-GF's transversely-mounted V6, inline 4's are child's play for plugs. Simply put, I don't mind changing the plugs and plugs are cheap for how long they last, regardless of the type.

That being said, I'm curious about these new NGK Premium RX plugs though I doubt their price justifies any increase in any kind of performance.

[bootymac]

I also note a good amount of performance restored when I change the plugs at my intervals. It it well known that plug condition matters far more than plug type. A new copper plug will be better than an old Laser Iridium plug in an engine.

This is why I ran copper core plugs on my (heavily modified) GTI. The frequent change intervals ensured that I constantly had fresh plugs for optimal performance. It also allowed me to examine the plugs more frequently to monitor for any potential problems. The price difference in the long run was insignificant and it gave me an excuse to wrench in the garage

The same logic can be applied when comparing Iridium IX to Laser Iridium. Despite the savings, I'm personally going to use Iridium IX as well. They last plenty long already given that I only drive 5000-6000km per year

[murcod]

I also note a good amount of performance restored when I change the plugs at my intervals. It it well known that plug condition matters far more than plug type. A new copper plug will be better than an old Laser Iridium plug in an engine.

Using a calibrated butt dyno?

NGK are in the business of selling spark plugs. They're hardly going to over spec the life of said plugs and loose sales.

Having said that, in the Kizashi owner's manual there are Severe driving condition servicing schedules in addition to the Normal driving condition servicing schedule. Each person should stick to whatever applies to their Kizashi.

Severe driving is described as:

Severe condition code:
A: Repeated short trips
B: Driving on rough and/or muddy roads
C: Driving on dusty roads
D: Driving in extremely cold weather and/or salted roads
E: Repeated short trips in extremely cold weather
F: Leaded fuel use
G: Repeated high speed drive or high engine revolutions
H: Trailer towing (if admitted)

I've attached both servicing schedules for reference.

Servicing Intervals Normal.pdf

(57.61 KiB) Downloaded 806 times

Servicing intervals Severe.pdf

(41.72 KiB) Downloaded 700 times

In addition, these are the plugs Suzuki are referring to when mentioning Iridium and Nickel:

Spark plug specification
Iridium type : NGK SILFR6A11
Nickel type : DENSO K16HPR-U11

http://www.ngk.com/product.aspx?zpid=10146
http://www.gsparkplug.com/shop/denso-k16hpru11.html