I've been readin up on this topic, but some sites (team-integra) favor platinum over everything else, while the majority favors iridium over all. Now I'm wondering whether they say platinum over all, because the article is old, or if there's a particular reason why I should use platinum, even when iridium is out. Can anybody shed some light on the matter? Which is better, platinum, or iridium. Thanks in advance

 

I <3 the "stock" NGK Iridium plugs.

(NGK + I believe they are called).

Whatever you do...please don't do the multi-headed platinum plugs.

IE: Bosch Platinum +2 or +4

 

I know about the multi headed, and why it's bullcrap. The spark doesn't go through both heads anyway, so having 2 heads is useless.

 

Can't really go wrong with NGK man.

 

what about denso. has anyone had experience with these plugs?

 

denso and ngk are both OE for hondas. my 02 crv has the denso iridium plugs from the dealer.

 

all right, thanks for the input here guys.. I appreciate it
Looks like i'm going for copper core iridium coated from either denso or NGK

 

NGK'S

 

yeah, my brother used to use NGK iridium on his starlet GT but recently switched to denso for no apparent reason

 

This thread isn't helping the problem. Yeah, everyone loves Iridium over platinum. But why?

The only thing I can think of is because with a smaller electrode, the spark will be more intense on that point.

Am I right?

 

copper is the better heat conductor from what i've read. with how easy it is to change plugs on our cars, and how cheap a good set of copper NGKs are, i see no reason to spend $ on platinum or iridium plugs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DamnYank! &raquo;</TD></TR><TR><TD CLASS="quote">copper is the better heat conductor from what i've read. with how easy it is to change plugs on our cars, and how cheap a good set of copper NGKs are, i see no reason to spend $ on platinum or iridium plugs.</TD></TR></TABLE>Although it's a better heat conductor, unfortunately it's melting point is much lower than that of platinum or iridium, and if you have a performance car, the higher the melting point, the better. Although i keep reading that for street cars, there is little difference in using Iridium or platinum, because it just doesn't get hot enough (on most applications) to melt either one of them.

 

Well, using http://www.webelements.com, I compared the Electrical Resistance for each element; Copper, Platinum and Iridium.

Definition of electrical resistivity:
The electrical resistivity, or specific resistance, ρ, is the resistance between the opposite faces of a meter cube of a material.

Copper: 1.7
Platinum: 10.6
Iridium: 4.7

By those numbers Copper is the least resistive metal. HOWEVER, as mention above, heat is a factor in the ability to conduct electricity.

Here are the melting points of each element.

Copper: 1984 degrees F
Platinum: 3214 degrees F
Iridium: 4471 degrees F


Now, based on that you can obviously tell that an Iridium tipped plug is going to withstand any heat and a normal combustion engine with give. Same goes for platinum. Now, Copper, most likely will have issues with hot applications, especially in Forced Induction.

So, given Iridiums lower electrical resistance and higher melting point that Platinum, it surely possesses better qualities. But, I would be willing to bet that both of the specs are so high that you will not notice a difference in these plugs if you switched

 

platinium cost $400/ounce so yeah that's why it so expensive...i just got NGK laser platnium that goes for $15 each

 

For the metal conductor in a spark plug, resistance is completely unimportant. It is not a factor. Remember, normal spark wires are resistor wires to suppress ignition noise from radios. The difference between the 1" long copper, iridium, or platinum conductor in a plug is the difference between 0.02 Ohm and 0.06 Ohms - effectively a dead short in both cases. Resistor wires have up to 1000 times as much resistance. Even non-resistor spark wires have more resistance than the plug electrode.

Standard plugs will wear at the edges of the electrode where the spark perfers to jump from. Lower temperature metals will wear faster. Years ago, it used to be that plugs needed changing every 15,000 to 30,000 miles. Some auto makers starting using platinum plugs to increase the mainatinence cycle to 100,000 miles.

Even though copper is a better thermal conductor, the iridium and platinum plugs are designed with different dimensions so the heat conductance from the tip to the body thread will remain the same.

I have heard some people claiming that under very cold starting conditions, they find that platinum plugs may misfire for a few seconds until they warm up.

What I would like to find out is if the multi-electrode platinum plugs work better? It's basically a question of fuel-mixture flow around the plug tip over RPM. I.E - the whole reason for porting some engines is to get a more effective purge of the cylinder in the exhaust cycle so more fresh air/fuel is pull in. Does the additional electrodes block fresh air/fuel flow around the plug tip?

 

whatever you do DO NOT get bosch platinum plus plugs.... they made my car sound like a subaru they misfired so badly/often!

keep it simple and you will be fine... go with NGK v-power and you will be happy!

 

ngk ftw