My NGK iridiums lasted 20k. After that they looked beat up. I suspected I was losing some horsepower and the starts seemed to take just a little too long. When I moved from the stock champions to the ngk iridiums my fuel eco went up 2mpg.

But, I read many articles on various web sites about not using iridiums in the srt-4. So, I went with NGK v power this time. I don't think I lost any horsepower or fuel eco.

Now, about spark plug gap.... the iridiums were stock at .045 I left them there. The champions were at .050 I have a stage 1, mopar intake and exhaust. It is really cold here in Indiana, and when the temp got around 20 degrees and I dropped the hammer the car did some hesitating at around 17psi. So, I moved the gap on the v powers from .048 to .036 (again after reading some reviews on line). This cured the hesitation at high psi. I am thinking about getting the msd ignition pack and moving the gap back to .048

 

the only time it's not suggested to use irridiums is on a big turbo, for whatever reason those seem to work better with a copper plug. that's not always the case of course, but often it is.

 

well i ordered the 4306's and the ngk iridiums the stock heat range now the delimma comes into play which ones do i want to use first any suggestions i have both sets sitting in front of me

 

i just put the 4306's in my car......gapped.050 seems to run good

 

well my car still feel' like it's missing......seems like more than with the stock spark plugs.....i also put msd wires.... any suggestions people?

 

Mine felt like it was missing at low idle. Seemed ok when I got on it. I also replaced plugs & wires and no improvement. Found out it was a weak fuel injector. Might not be your trouble but if it's still under warranty, let your dealer do the guess work. Good luck.

 

I just love how most everyone rags on Champions saying what crappy junk they are and I've never had a problem with them. I've tried just about everything out there and I've always been brought back to the cheapy Champions. I usually would change plugs once a year out of routine, which I think anyone should with any high performance car, and with averaging only between 6,500 and 7,500 miles per year it doesn't really leave much time for failure. I have waited longer and I currently have never changed my plugs in my SRT-4 and it just topped 14,000 miles without any noticeable performance loss. I also haven't changed the Champions in my Roadrunner in years, mainly due to the difficulty with the headers in the way and having to extract most from below, but it starts and runs perfectly still. Most if not all serious racing types use the basic cheapy Champions and if it's good enough for them, then it's good enough for me. And if you want to compare prices, changing the cheapy Champions every year or so is still far cheaper than buying the high dollar plugs every several years and it has the added benefit of letting you see exactly how the engine is running when running and changing the Champions every year while still being cost effective. I think the Champions get a bad wrap because they are so cheap and are the stock plugs, which most tend to think because they are stock and cheap that they are automatically considered junk. I'm here to say that the cheapy $0.99 Champions cannot be beat and are reliable and unfairly discredited.

 

Congrats Roadrunner... since I work for NGK... I am forced to say Champion suck

seriously though... you are an oddity for it... (and that isn't a slam). a large percentage of people have trouble with the Champion's... at least in these cars. Use what works best for you! No harm there!!

 

For years it was known that copper plugs make the most horsepower. Other types may last a lot longer, but you lost a little bit of power. But now, even everyone in the NHRA has changed to iridium plugs because they make more power than a copper plug. Every dyno test I see shows how just changing to iridium plugs gained them a few HP.

So unless you want to pay extra for iridium spark plugs, just stick with copper. I use Champion copper plugs all the time, no issues. You are right 71RoadRunner, change your cheap plugs often, and see how your engine is running.

 

As I have said, I've used most of the plugs out there at one time or another, but I have never tried the iridiums, so I cannot say how they are.