Iridium vs Platinum

[nthach]

Originally Posted by PimTac

There is nothing wrong with platinum plugs.

++. I wouldn't lose sleep over it. Change the plugs at Hyundai's recommendation or when you see the CEL blink and P030x misfire codes are present for troubleshooting.

 

[kschachn]

Originally Posted by nicholas

Its platinum in the manual. I came here to see if anyone knows why a platinum was used as an OEM plug......... Lots of conjecture and judgement but no real answer to my question...

Again, there is no performance difference between the two. If you perceived one then it was due to one being worn and the other one being new. They use platinum plugs because they are less expensive than iridium and they are acceptable for use to achieve the specified replacement interval in the owner's manual (and emissions warranty requirements). No other reason. My two Toyota cars specify platinum plugs and both go the 90,000 or 100,000 mile interval without problem. I could use an iridium plug instead but I really don't want to leave them in the head any longer from personal fear of seizing.

 

[Jimzz]

Originally Posted by nicholas

Its platinum in the manual. I came here to see if anyone knows why a platinum was used as an OEM plug......... Lots of conjecture and judgement but no real answer to my question...

Iridium is in the Platinum group. That and iridium plugs are iridium on the tip and platinum on the ground.

 

[Dave9]

Platinum is used because it works acceptable for the warranty period. Platinum works equally well as a fine wire plug except does not last as long as a fine wire iridium. Since you don't get to pick which plugs come from the factory, you should consider how often you are going to replace the plugs. If the vehicle burns oil for example you are going to need a shorter replacement interval and may be wasting money on iridium. If it does not, it is arguably worth using iridium on the first plug change. On subsequent plug changes, 2nd/3rd/etc, I'd just go platinum fine wire and change them more often. It's good not to leave them in too many years so they aren't seized in place and to examine for hints of an engine problem. At least that is my strategy, I tend to get newer vehicles every few years so the older a vehicle gets the fewer miles are put on per year so the more years before X # of miles would otherwise wear out spark plugs, then with either type it has been long enough that I'm replacing the wires while I'm at it, and on some vehicles with a coil on each plug, it may be time to replace the coils too... replacing something old before it fails can be cheaper than a tow, but of course there is only so much it's reasonable to do but I'm talking about well over 100K mi by that point.

 

[Gimpy1]

Why are you trying to out engineer the engineers? Its a brand new vehicle leave it alone don't fix what isn't broken and simply follow the owners manual. If you switch to a different plug it may invalidate your warranty. Throttle response can be affected by a ton of things from the TPS all the way to the shape of the throttle body and intake.

 

[Kestas]

Originally Posted by nicholas

I came here to see if anyone knows why a platinum was used as an OEM plug......... Lots of conjecture and judgement but no real answer to my question...

You want to know why platinum was used versus what?... iridium?, or regular untipped plugs?

 

[UG_Passat]

Originally Posted by kschachn

Originally Posted by UG_Passat

The spark plug makers did find decreased center electrode diameter requires less energy to spark and produced a "more concentrated" spark for a better start of the flame kernel.

It is about geometry. Iridium has a much higher melting point than platinum and as a result the electrode can be made smaller despite poorer overall heat conduction.

It's not about heat conduction. That is a property of the heat range of the plug, defined by the geometry. Iridium alloy is expensive and not as good as a conductor, so the tip is small for cost, and it's only the tip. The rest of the core is still nickel alloy. The byproduct of the reduced diameter is less energy to spark and a "more concentrated" spark (in laymen's term).

 

[kschachn]

It is about heat conduction, a small tip is desirable for several reasons and that isn't achievable with a standard nickel electrode. The heat cannot be conducted away fast enough and it will melt, but this won't happen with a platinum group metal. The one thing it is not about is electrical conductivity. The overall electrical resistance of the plug is far higher than anything going on at the tip. Besides, all the platinum group metals are excellent electrical conductors.

 

[Mad_Hatter]

Originally Posted by Gimpy1

Why are you trying to out engineer the engineers? Its a brand new vehicle leave it alone don't fix what isn't broken and simply follow the owners manual. If you switch to a different plug it may invalidate your warranty.

If the design engineers felt the cost to benefit favoured iridium, I'm guessing they would have put them in there. Especially when you consider putting in iridium at the factory isn't exactly going to move the production cost all that much. That said, if the marketing dept thought they could charge $10k more for the vehicle because it has iridium plugs, they'd push for having them in there....‚ But hey, it's your car now and your money... you do you! It's a waste of money IMO, but you know what they say about opinions.....

 

[Snagglefoot]

Why are you old boys talking about Platinum and Iridium? Ruthenium is where it's at!

 

[ARCOgraphite]

I use a micro MASER injector to ignite my spark! Ceramic plugs are like 2 centuries ago. Static electricity - Ha! So Ben Franklin.

 

[Mad_Hatter]

Originally Posted by Snagglefoot

Why are you old boys talking about Platinum and Iridium? Ruthenium is where it's at!

Because I've never been fond of the name Ruth. I'll pass until they come out with a Nancyinium or better yet Vibranium. If it's good enough for the Cap', it's good enough for me! ...‚

 

[UG_Passat]

Originally Posted by kschachn

It is about heat conduction, a small tip is desirable for several reasons and that isn't achievable with a standard nickel electrode. The heat cannot be conducted away fast enough and it will melt, but this won't happen with a platinum group metal. The one thing it is not about is electrical conductivity. The overall electrical resistance of the plug is far higher than anything going on at the tip. Besides, all the platinum group metals are excellent electrical conductors.

Heat range is all about heat conduction, which is usually related to nose insulator length. For a specific heat range, spark plug manufacturers will offer different choices in the tip material for different costs and performance. Platinum group metals are not good in terms of electrical conductivity, or thermal conductivity either, which is why modern precious metal plugs use very little of it and alloyed with other metals to improve conductivity. This is why for modern precious metal plugs, the core is still primarily nickel alloy. The precious metals are used for hardness, for the durability, not the thermal or electrical conductivity. I say "modern" to exclude the old Bosch Platinum plugs which they claimed had a full platinum core. If they are excellent electrical conductors, why haven't we seen Platinum group metals replace copper when it comes to electrical wiring, circuit boards, etc? If the EGT's are so high that you're melting spark plugs, something is wrong.

 

[DoubleNickels]

Originally Posted by Gebo

I am of the "opinion" to only replace spark plugs with OEM. Many people don't hold that view, however. I believe ignition systems are designed with a particular type of plug in mind. Be it platinum, IR, etc.

It varies. Depending on the manufacturer. Depending on the specific car. Maybe a different plug could work better. Maybe the OEM plug was the least costly option, because not every car is sold with your satisfaction in mind. Look at some of the OEM spark plugs, all the problems they had with them, and you may scratch your head a little.