Apex1.0

In my experience nothing beats a fresh copper plug for engine performance. I know platinums and iridiums increase the service interval. But do they increase engine performance?

I am interested in hearing other opinions.

Syn

As I've understood it, they break down as such:

Copper: Cheapest, best performance, shortest lifespan
Iridium: Most expensive, nearly as good as copper performance, long lifespan
Platinum: Nearly as cheap as copper, average performance, longest lifespan

If your car is not boosted I don't see a need to run anything other than a quality platinum plug. It meets the performance needs and lasts forever. Then again these cars are easy to service so I wouldn't fault someone for running coppers and changing them every 5-10k.

zeroptzero

Everyone will have their preference, here is my two pennies.

Copper plugs are the lowest cost, they tend to give a good spark, but you will have to replace them more often. They usually have wider center electrodes and wide ground electrodes. As the center electrode wears it becomes shorter and your gap opens up, the plug gap service limit on these engines is about .051", use that as your replacement parameter. I don't mind changing plugs but I don't want to be doing it all the time.

Higher end platinum plugs like the oem variety wear longer than lower cost copper plugs, and they cost more. The center electrode is a bit thinner which helps performance, the ground electrode is about the same width as copper plugs. Oem plugs are rated for 100,000 miles, mine were worn past the service limit at 55k miles, but who really wants to keep the same plugs in their engine for 100,000 miles anyways ?, not me.

I run NGK Iridiums Hyper IX series. They have a thinner center electrode which is better for performance. Iridium is harder than plat and copper so they can use a thinner electrode because of that. But it isn't too thin like the Denso Iridiums which have been known to break. The center electrode wears slower than plats or copper so the gap remains stable over a longer period of time. The NGK Iridiums in the Hyper and IX series have tapered ground electrodes which is better for performance for better quench properties. I'll probably change my plugs every 3 years for peace of mind.

Some say copper is a better conductor than platinum, I'm don't know for sure either way, but performance is also affected by the design of the plug not just the material. I don't push any plug on anyone, use whatever you feel is best and depending on your situation. I do think that NGK makes the best plugs for our vehicles, and they make plugs in all three varieties.

redlineracing

On the "Butt Dyno" ,I doubt if you could tell much diff between materials.On a real dyno,maybe 1 or 2 hp.

I run NGK BKR7E Gap .040 on my 03 with 99k miles.Good,cheap ($2 ea) and have a service life of approx 25k miles.

That's just my opinion.I run NGK coppers on all my cars listed below EXCEPT the '13 EXV.After the warranty is up,I'll switch it to them as well.

\rlr
Carolina

Eluded

personally i like the rhodium spark plugs.

Saki GT

Fwiw, for all the talk, I've never seen anyone dyno a car with different plugs to show any differences.

zeroptzero

The difference would be minute if any, but over the long term having a plug with a more consistent gap is likely where the benefit lies. If you change your plugs before the plug gap grows too far then they all should be sufficient, but many people don't bother to check and that is where performance differences can show up.

Apex1.0

That was my thought too. Assuming equal gap and good condition, power wise they are all the same. I know when I was more involved with FI and drag racing. Many of the fast 8-9sec guys, would only use copper plugs. Most likely because they change them all the time.

Saki GT

If that's the case, I'd just stick with Iridium.

Merknsissys

From all my boosted B-series days copper plugs are the way to go since changing plugs in our cars takes less than 5 mins and plugs are cheap and proven.