NGK Iridium Spark Plugs - better than normal plugs?

tallon · 5-10-07, 9:41

I've just bought 6 of these online for around £48 as I was told they would improve both performance and consumption - anyone have any experience of these plugs in an MX6? and do I also need to upgrade my leads?

**N0DDY** · 5-10-07, 10:12

As far as i'm aware, a spark is a spark, as such better quality plugs shouldn't improve performance or consumption, but may last longer than normal plugs. I might be a million miles off here, not entirely mechanically minded when it comes to cars.

**supersparky** · 5-10-07, 11:53

the idea in a petrol engine is to get a good strong spark with the largest surface area possible to ignite as much of the petrol as possible leading to better combustion , more power ect.

so you get the Bosch plugs with the 4 electrodes and Alfa's t-spark

the iridium plugs have better more durable contacts so in theory the spark will stay stronger for longer as the contacts/electrodes are less effected by the constant spark combustion process.
the temp of the spark and the explosion of the petrol take their toll on a spark plug.

as for if they improve performance or consumption in a lab or on a test track i would imagine they do, in the real world with traffic jams,weather and loads to lug i don't think you would See a difference just longer life.

i have them fitted in both my mx 6's

gareth

**Einstein** · 5-10-07, 18:03

Nope... Noddy is right, a spark is a spark..

As for the super 4's and other multi electrode plugs (splitfire etc)
they just last longer because of the erosion properties..

they will only spark to one electrode at a time, not all 4 (or 2) what happens is as the electrode wears, the spark will always go to the shortest path, hence another electrode, as that wears, it goes to another etc etc, so in theory, it should last 4x longer than a normal plug.

Irridium plugs have a very small electrode, giving less of a surface area to foul up, so stay cleaner for longer, also the irridium is very hard, so they last much longer..

There are no performance gains for any plugs, just some last longer than others.

The only thing I have noticed, is some engines don't like certain plugs.. and run better on those recommended by the manufacturer... early Bosch plugs were the cause of many problems in a lot of cars we had in the garage, changing them cured the bad running.

John

**JLCustomizing** · 6-13-07, 23:29

Ok all this is good and all but what ive been told is the spark plugs have hot and cold spark, i had bosch +2 in mine and the spark was so hot it killed my plugs in about 2 months. But NGK is a colder spark, which is what our car originally came with. So who knows the car better then who made them so NGK is the way to go on the mx6, however running iridium (which i have) just gives a stronger, more reliable spark.

**Einstein** · 6-14-07, 3:44

Nope...

You get hot and cold plugs, but it's nothing to do with the spark...
It is the length of the insulator that gives the temperature rating, and you put in the correct heat range for your engine... too hot, and the plugs will foul up easy, too cold and you risk detonation..

As a guide, an old lawn mower of an engine will use a hot plug, and a V8 F1 engine will run a cold plug.

As for the irridium plugs, (which I use as well) the spark is no better than a normal plug, but because of the very small electrodes, it will not foul as easy, plus the very hard material will make them last a lot longer... but that's it, no performance gains at all (when new) if you take a look after 10000 miles, then the irridium should be working better than a normal plug, but only for the reasons above...

John

Paula · 10-20-07, 16:36

My old standard NGK plugs that were in pretty good condition still were changed to NGK Iridiums by Nick Clulee in Sheffield on Tuesday.

The before and after is quite amazing and the car simply flies now.

The HT leads were replaced the previous week, so it was not them that made the huge difference, but they did improve the car quite a bit but not as much as the plug change this week.

Paula

tallon · 10-22-07, 5:22

Yes, I experienced the same thing when I fitted them in my MX6 - a definite noticeable improvement (when I wasn't expecting to notice any). Presumably my old plugs were really crap and this returned the situation to normal. I understand the tech rationale the other guys have written about, but it seems to me that since they will foul less easily and last longer they will probably perform better that std plugs when the engine is under a load and perhaps nearing a service date even if they don't add any extra power etc.

David