NGK Platinum vs NGK Iridium? Worth it?

[fdhj324]

Originally Posted by Blue Bomber

To get a better spark, you need to use a good conductor. Copper is one of the best conductors available for spark plugs

Sorry, but I came across this in a Google search and it is complete nonsense. The resistivities are Platinum = 1.06×10^−7 Ωm vs Copper = 1.68×10^−8 Ωm.

The total resistance of the copper/platinum/iridium conductor is maybe billionths of an ohm. Meanwhile, it's in series with the spark plug wires, which typically have a resistance of 10,000 to 15,000 ohms. So you're talking about a difference between 10000.000000001 ohms and 10000.000000006 ohms. The difference between the conductivity of copper and platinum is totally irrelevant, and couldn't even be measured.

Platinum is used because it's more durable, not because it's a better conductor. (Same for gold-plated audio cable connectors, incidentally.) This allows it to be made into a narrower electrode without eroding away as quickly as copper would, to make it sharper (higher electric field strength = easier to arc), and to absorb less heat.

[ShadeTreeMech]

the only advantage I can think of of iridiums is the possible longevity of iridium vs platinum vs copper. Some cars require an act of congress to change the plugs, and for not needing to change pugs for 100k miles, I would gladly pay more. That and the iridiums/platinums are supposed to give a stronger spark when worn out compared to same miles of copper plugs.

[mwebb]

as a long time scope guy , i will say most
(but not all)
of the info in this thread is pure nonsense

what is true is that copper plugs do not last as long as the others
unless
the engine is using a wee bit of oil
then
all three last about the same amount of use / miles

platinum plugs tend to foul easier and stay fouled once fouled
iridium are not much better

copper is the cheapest and electrically the best of the lot , but

the spark plug that was designed for the system by the engineers who designed the system is always the best choice for that particular system

use the OEM recommended brand and part # ONLY for best results

if any one of you can post a scope waveform showing any inaccuracy in this post
do it now -
allow me to save you the trouble
there is no waveform that will invalidate this post

stop this nonsense - use the OEM recommended spark plugs only.
there is no super plug , only snake oil .

or spend the dollars , acquire the skill and learn about ignition , then with your new skills and equipment , out engineer the engineers who designed your system - rots a ruck with that .









the last image shows a "bad " secondary spark waveform 1st caused by leaking valve , 2nd secondary spark waveform is a "good" waveform ,2 cylinders of 8 culled from a much larger file using a high resolution scope .

you can not fool an ignition scope
there are no better spark plugs than those the system was designed around

do not attempt to out engineer the engineers
unless you enjoy chasing your own butt .

[Phileaux]

Mwebb,
So you have the OEM: tires, filters, dealer supplied fluids in your car?? Unfortunately, vehicles are designed by engineers but built by business men. When CompanyX needs tires for 400,000 vehicles they get bids for the lowest cost option that satisfies the minimum required standard. I was a service writer at Sears during the upsurge in H,V,Z speed tire. Watching high speed video of the distortion of a tire, at highway speeds, you can see the difference between 'Ok' and 'Better'. If engineers had the final say so every car sold would have a reusable air filter. I'm saying, don't look at the vehicle as a feat of design & engineering, it's a creation of design, engineering & marketing.

[mja1]

Originally Posted by Phileaux

Unfortunately, vehicles are designed by engineers but built by business men.

this is true. I've never understood why more companies don't listen to their most educated/respected sales persons on product design. These are the guys that really know what needs to be done for the business men to make money and to bring the engineers back to reality.

Engineers/mathematicians have a tendency to over-analyze just about everything, then we end up with much more than needed for a lot of things that aren't used. Add to that business men that try to cut costs on those unnecessary/superfluous/over-engineered pieces, its a wonder how more products and vehicles don't end up heaping piles of dog crap.

[Marc F.]

For 21 years I did specialized metal casting. Copper is relatively easy to melt. I had to cast platinum, its melting point is about 3220 degree F. I think. I can see that making the plugs last longer. Each time its fired a fractional amount of metal is erroded by the very hot spark.

I have no idea about irdium. Also the alloys make each metal behave differently.

Metallurgy has advanced quickly from when my car was built to now (1982). The original engineers didnt know about the plugs we have now. But as its pointed out profit is involved too. While we can afford more $ per plug for a better product if you multiply that by 300,000 units yearly it makes sense to use a cheaper plug if it does a good job.

I can't agree that only using a manufactures recommended plug is the only way to go. We are modifying our engines/cars and running them in ways never even concieved by the original engineers. Learning to read the plugs like hot rodders do is what I would do. The original may be the best choice but it may be the wrong heat range after you tweak everything else on the engine.

By the way I chose the OEM recommended spark plugs, money was a concern. But with some of the engine mods I may have to change them.

I have noticed a trend in various threads to state "this is the only way to...you have no idea what your talking about, etc, etc". The problem is that our personal way of driving, modding, and where live is never considered. I am trying to add to information, not tell anybody they are wrong.

[Fosters80]

+1 for OEM plugs, especially in a Honda. Not sure why, but I would say 95% of the misfire complaints I dealt with were the result of aftermarket (Bosch, Autolite, Mighty, Champion,..) plugs. The other 5% was worn standard OEM plugs.

Honestly I can't say I've done any comparisons as far as economy or performance goes to compare the different types of plugs. I can say though that the Iridium plugs last a really long time! I think alot of it has to do with manufacturers trying to lower the cost of ownership for J.D. Power ratings.

[straight5]

I'll stir this pot a little more lol
In my Saab,

The system puts a low voltage over the spark plugs when they are not fired to measure ionization in the cylinders. The ionic current measurement is used to replace the ordinary cam phase sensor, knock sensor and misfire measurement function.

Saab Direct Ignition - Wikipedia, the free encyclopedia

So yea, some of us have to use the recommended plugs.

But I also believe that wear in the engine, age, modifications, and other factors may be considered.
After changing plugs many vehicles, I believe that indexing works for some cars, but not all. The gain for me was quite small, but the cost was small too - only 1 extra spark plug. Neither gains nor cost are enough to argue.