http://www.acdelco.com/html/pi_plugs_rap_main.htm
From the Horse's Mouth... These plugs have had a lot of good feedback.
Spark Plugs
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From the Horse's Mouth... These plugs have had a lot of good feedback.
How long do platinum plugs last? My 2003 Toyota Echo is equipped with factory platinum plugs. The dealer suggests to replace them after 60k miles. They also suggests my fuel filter in the gas tank is lifetime and no need to replace it. My car has about 32k miles now. Should I replace my plugs now?
BTW, the older model of Echo received factory Iridium plugs good for 100k miles. Not sure why Toyota switched to platinum plugs later. Cost cutting?
Denso seems to have three iridium series. I'm looking at the picture of the "Iridium Long Life", and there seems to be some sort of spot fused to the ground electrode. Then there's the "Iridium Power" and "Iridium Racing" series. If the long life version isn't available for the original poster, then I'd think NGK or Denso platinums, or NGK Iridium IX would be the ideal choice.
The pics are on the front page of the website:
http://www.densoiridium.com
I realize that sometimes the factory O.E. spark plug is where you can't go wrong. However - NGK was known to make many of the factory long life spark plugs for GM vehicles.
Platinum plugs come standard in millions of cars from the factory. Of course they work well.
It is not the best possible conductor, but lasts a longtime, and work very well because plat plugs have very narrow firing tips. This offsets the slightly worse resistance.
It is not the best possible conductor, but lasts a longtime, and work very well because plat plugs have very narrow firing tips. This offsets the slightly worse resistance.
Platinuim plugs were a godsend to me (typical oiling late 70's Chev 350), as two cylinders had to be changed every 6m or else. The BOSCH Platinums held that off for a good 15m miles which made for an annual tune-up instead of a spring/summer deal.
The Iridiums I have pulled from cars (all with in excess of 60m) have looked and worked fine. I therefore went with the DENSO Iridiums in my DODGE V8-318 when I did a major tune recently. Two cylinders are affected by an intake manifold leak, and the plugs were carboning up.
Expensive, but I can't really work on cars anymore due to health, so I try to keep owner service to cool days and easy jobs. Plus, the dealer charge for sparkplug replacement, even once, pretty well covers that cost. I expect to go 60m prior to inspection once manifold problem fixed.
As to fuel mileage, on an OBD car, chances are good that the EXACT plug as came from factory is the best choice. Not to mention for cleanest cylinders as well. Modified cars are another story.
The Iridiums I have pulled from cars (all with in excess of 60m) have looked and worked fine. I therefore went with the DENSO Iridiums in my DODGE V8-318 when I did a major tune recently. Two cylinders are affected by an intake manifold leak, and the plugs were carboning up.
Expensive, but I can't really work on cars anymore due to health, so I try to keep owner service to cool days and easy jobs. Plus, the dealer charge for sparkplug replacement, even once, pretty well covers that cost. I expect to go 60m prior to inspection once manifold problem fixed.
As to fuel mileage, on an OBD car, chances are good that the EXACT plug as came from factory is the best choice. Not to mention for cleanest cylinders as well. Modified cars are another story.
I can't imagine that the difference in resistance between nickel, platinum, iridium, etc would be any more than 1 ohm (if that) for the small lengths used in the electrodes. The vast majority of plugs these days have a series resistor in the range of 5,000-10,000 ohms. Typical spiral-wound plug wires will add at least that much resistance depending on length.
The hardest thing for the ignition system to overcome is that it has to create current across a compressed fuel/air mixture and a coating of oxidation on the electrodes. If you take a look at a double platinum plug, there's usually not much oxidation on the platinum. A standard plug will be covered with a nice layer on the ground electrode, and a thinner layer on the center electrode.
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Bosch +4 spark plugs were crap in my 2.8 V6 12 valve Audi engine. The puny center electrode burnt off, the other electrodes fouled each time I used a fuel system cleaner (Techron). OEM nickel-plated NGK tri-electrode spark plugs perform way better.
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The Bosch code looks, for example, like this:
F7LTCR
in this case, 7 is the heat index number.
the +4s are working perfectly in my Camry after about 10k miles.
Spiral wound wires sound good, but the energy actually travels on the outside of the windings with a plasma field - the windings don't do jack squat.
Spiral wound sounds good, though.
Spiral wound sounds good, though.
I probably should have also mentioned resistive plug wires in general; I believe most are carbon doped to increase resistance? I used an ohmmeter on a set of plug wires, and they measured from 5K to 10K ohms per wire. The basic point I was trying to make is that the resistance of the body and electrode metals is going to be neglible compared to the high resistances intentionally placed in order to reduce electronic interference.
OK - I still can't figure out how they're supposed to control heat. It's barely any metal, and none of it is sticking out past the insulator. I looked at one (Bosch +2) in the store yesterday.
My apologies about the heat range comment. A little research did me some good. I was under the impression that more than nose cone size controlled heat; I had the incorrect impression that the electrode tip length also varied. However - I still have my doubts as to whether that thin platinum wire can remove enough heat during varying conditions. A more conventional platinum plug has a wider nickel alloy sitting outside the insulator. My concern is that the only path for heat transfer is through this thin platinum wire.
I'm not sounding any alarm bells. Most people seem to be using them with no problems. It's just that my mechanic tried Bosch platinums in the late 80's/early 90's and had quite a few spectacular failures. The platinum would loosen or vaporize. From then on, they went with ND (now Denso). Most of the warnings I've heard against using Bosch platinum plugs are with Japanese makes. NGK and/or Denso are so easy to find, so why risk it?
This guy had one that jumped out of the insulator and apparently banged against the ground electrode until it was shaped like a mushroom. He's still happy to use them after Bosch sent him 8 plugs for sending the one failing one in.
http://www.deathstar.org/~flash/bosch.html
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y_p_w, I second your concerns regarding the Bosch +4 spark plugs. The center electrode burnt off and was miles buried in the insulator after only 12k (I think). Even Bosch Service guys have repeatedly told me not to use the +4 plugs and said the amount of platinum used was miniscule. I know the +4 spark plugs work well in some cars, but for my Audi they are a bad choice.
Found another quote in the Denso Iridium FAQ. The Denso "Long Life Iridium" also has a platinum tip on the ground electrode. The "Iridium" and "Iridium Power" plugs have the "U-Groove" ground electrode.
http://www.densoiridium.com/faq.php
My experience with platinum tipped ground electrodes is that they stay very, very clean. I've got a few pulled out after about 70K miles, and the nickel portion is covered with lots of oxidation, but the platinum tip still looks like metal.
I regularly use Techron to clean the fuel system. I have used two 12 oz bottles of Techron back to back currently because of pinging problem. With 32k miles on the factory platinum plugs I wonder if I should replace them. What kind of syntoms do your engine show when its plugs are fouled by carbon?
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Rough idle, hesitation, and poor performance can be caused by fouled plugs. Driving the car at high RPM may help clean deposits off spark plugs.
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