I know im If the Iridium is supposed to be a far more rare metal than platinum, why is the Platinum PFR7G-11S about the same $$ per plug. At least at the auto parts store.

 

I can't get this across in a poll, so here is my opinion. If you are the type to install your plugs and don't look at them for 100k miles go wtih the stock platinums, they will last longest before the gaps increase. They are expensive because you have platinum on both ends.

If you don't mind pulling the plugs every 1-2 years to inspect and adjust and replace when necessary, then I like the slight performance increase of an Iridium plug. You get a thin yet strong center electrode and a tapered ground electrode - the NGK IX Iridium series. I run them in my S2k, and I will run them close to the maximum gap .043" as I'm checking them on a regular basis. The other plugs will start at the lower end of the gap spec which gives them time to grow (widen)

 

thanks. i pmed you back about the rad.

 

I've been running NGK Platinums for a year or so now with no complaints.

 

I'm under the impression both go the same distance.

I cannot tell the difference between plugs.

 

I think both of those plugs do last equally long as they each have a platinum disc on the ground electrode to reduce erosion of the ground electrode. The Iridium plug center electrode should exhibit less erosion over time being a harder metal. I can't tell if the center electrode of the iridium plug is thinner than the platinum plug, they are both labelled as fine-wire, they usually are thinner with Iridiums which gives them a performance benefit.

The Iridiums I use are NGK BKR7EIX-11, they have a tapered ground electrode along with a thinner ultra-fine .6mm Iridium center electrode designed for the best performance. They don't have platinum discs on the ground electrode, hence changing them every few years is needed.

 

I have put 100k miles on NGK Iridium plugs and the center electrode was just like new after 100k miles, the ground electrode was almost gone(non-platinum). Great plugs.

ROD

 

I always assumed iridiums were a fair price difference. Is the benefit of ix plugs the longevity or performance? From a harder metal and smaller electrode equals better combustion?

What gains did you notice?

 

The benefit of the NGK IX series of Iridium plugs is mostly performance. They have a thinner centre electrode (ultra-fine wire) with a tapered cut ground electrode, which gives the benefit of a more focused spark, less quench etc.... , firing with less voltage requirements, less misfires and better combustion in general. The ground electrode will wear over time as it is just regular steel, they are not designed as 100k mile plugs. The centre electrode should wear well as Iridium is harder than steel and plat. The 100k mile plugs seem to use a plat. disc on the ground electrode and they typically do not have a tapered cut ground electrode.

I use the IX series plugs in hopes of getting a better performing plug, I like the design of the plug, and I'm willing to change them every few years. When I put these plugs in my engine they replaced the 7 year old factory plugs, which had gaps opened up to well over .051" after 55k miles. My car definitely performed better but I'm comparing new plugs with old plugs. I don't want to promise any definite gains but the design of the plugs are designed to improve performance, much like Denso Iridiums (which use the thinnest centre electrode in the market). I also like Champion Iridium plugs which are designed similarly to the NGK IX plugs, but Champion's heat ranges seem more confusing to me so I'll stick with NGK where you can stick with heat range 7 and be sure of it.

 

went with the iridiums guys. $40 bucks at O'reilly's