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The Duratec Sparkplug Sticky

157K views 255 replies 89 participants last post by  Billythakidd1113 
#1 ·
There is too much confusion and misinformation out there, so I'm going to simplify everything.

First off Here's a quick do and don't use
Do Use
OEM Plugs from the dealer
Autolite, "coppers"
NGK "coppers"
Don't Use
Anything made by Bosch
Designer plugs
Autolite Platinums

Secondly, I'm not going to touch Forced Induction, Nitrous, or 30+ hp gains

I'm going to base this off my 2006 D20 (vin N) non p-zev.

The Focus comes with "Motorcraft" Spark Plug made by NGK.
Yours may have come with a DOUBLE PLATNIUM plug.
The reason your Focus came with this type of plug is for 1 reason only. THE BEST SPARK OVER THE LIFE OF THE PLUG it is a tricky play on words but just read it it seems simple enough. They're not making any claims beyond long life. You can expect 80-100,000 miles out of factory plugs.
www.fordparts.com offers the OE replacement for $18.19


There are a few different options available out there. Other manufactures who make a factory replacement, there are cheaper options, and then there are designer plugs.

I'm not going to touch on the designer plugs because if it's too good to be true...

I will say that the Bosch +2 and +4 work wonders, on BMWs from the late 1990's to the early 2000's. BMW contracted Bosch to come up with a plug to help clean up emissions. Bosch, like any smart company decided well heck, we can make a fortune off this. However, BMW stopped using these around 2005 when they released their "N" generations engines. Now BMW only uses Bosch spark plugs in a 1 or 2 engines.

The bottom line is Bosch +2 and +4 plugs will never perform the way they were intended on any car other than what they were designed for.

To begin with there are many companies making a good double platinum spark plug, but I will say that with the double platinum spark plugs that modern cars are designed so tight that you really need to stick with the original manufacture of the plug to have the car running right. There is no government control over the spark plug industry and the thickness of the platinum from manufacture to manufacture is going to vary.

Now onto replacement options.

You're first replacement option is to replace the spark plugs with the ones it came with. In my previous rambling, as mentioned you really want to go with the plugs from the Dealer, yes I know it sucks. But when playing with platinum you're just that, playing. You can try the replacement plug from NGK in the NGK box, but you really don't know if you're getting their 100% quality. If you go to the dealer and buy them in a Motorcraft box you know for 100% fact you are getting the spark plug designed by NGK for Ford. Unless your parts guy is an idiot and there are a lot of them out there, so do your research and ALWAYS ALWAYS ALWAYS go into the parts counter with your vin#.

You're second replacement option is to go with an iridium plug. Iridium plugs have not been around that long, and were introduced to make the longevity of the plug last to a true 100,000 miles. I think we all know someone with 80,000 miles on there vehicle with double platinum plugs and it started running like crap, and the plugs were just worn out.
In my opinion, iridium plugs push the line of designer spark plugs, and only reason I included them is becasue, there are a few manufactures using them now.

Now onto the confusion. Copper spark plugs.

To begin I will only be covering Autolites, however NGK makes a quality "copper" plug as well.

Why copper?
Copper conducts electricity much better than anything else on the market.
Why not copper?
It's life is about 1/10 that of a platinum plug HOWEVER at 1/10th the price, you do the math, if you're time and labor are free you're not really losing anything in the end.

All copper plugs from Autolite, are part #'s A### OR AR###
That's it, if it says AP it's not, if it doesn't have an "A" or an "AR" infront of the part number it's not copper.
We have 3 choices when it comes to copper
The Autolite A104
The Autolite A103
The Autolite AR103

I will breifely touch on gapping after this next rambling.
I always gap my D20 non pzevs at .055"

The A104 is of the factory Heat range, it is considered a replacement plug. You may or may not feel a gain with this, but you will feel your vehicle idleing smoother and possibly a decrease in fuel consumption.

The A103 and AR103 are a heat range lower.

A lower heat range works by allowing the heat to dissipate faster across the spark plug. This is benificial to us.

The advantages of a lower heat range:
lowered combustion temps
lowers chance of pre-detonation
burns fuel more completly, this is the one that makes us power and decreases fuel consumption
lowered emissions
The disadvantages:
There is a higher chance of the spark plugs to become fouled because it is cooler and if you have OTHER ISSUES SUCH AS LEAKING INJECTOR, it's going to cause the electrode to get wet and it will never get hot enough to burn that wet fuel away. If you're fouling a 1 step colder range on your focus, you have other issues going on.

First the A103, a good plug you will notice results from this. Your car wil be quicker, it will idle better and you're fuel conspumtion will decrease.

The AR103 is identicle tot he A103, but it has a groove cut in the electrode and the electrode is nickle plated. It is also way more electro magnetic interferance resitant than any plug out there, which is not benificial to us using coil on plug, but still nice to know if there is ever an EMP attack our spark plugs will still be ok. lol The AR103 will be less prone to fouling and carbon build up, which may results in a little longer life. But the big thing for us is the groove cut in the electrode, the idea behind this is to make a wider flame front and it works well and will make 5hp over stock plugs on a stock car.

On to life and gapping.

If you gap the spark plug to the factory recomendation of .050" you should see 30,000 miles from them, however reducing the gap will reduce your hp gains, as you want the spark to jump as far as possible without extinguishing it's self to create a better flame front.

If you gap the spark plug to .055" you should see 15,000 miles. This is the best compromise in my opinion. The gap make the spark huge and will give you a much improved gain over stock.

You can also gap to .060" however I do not recommend this unless you keep a set of hand tools in your car. This will make a very nice gain, however life until the gap becomes to large is very short. When I ran .060" I swear it felt so much better and was getting around 38mpg highway. However, after 8,000 miles started to misfire. and when I checked the gap they had grown to .062" and i guess .062" is just to much for the coil on plug to handle.

Conclusions
If you want longeveity, go to your ford dealer and suck it up and buy the OE plugs
If you want more power and better fuel consumpion, go with the A103 (or AR103 if you can find them)

Hope you enjoyed. Any questions feel free to PM me.
 
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#2 ·
Good info.

I used Autolite 104's when I was NA and now use 103's with the boost.


When I go to the parts store; I DO NOT tell them what car it is for. I simply ask them, "Can I get the 4 pack of Autolite 103's (or 104's)?" No questions asked; I don't let the guy tell me whats best for my car.
 
#4 ·
Wicked, I just started clapping in my cubicle as I finished reading this thread. Your information has greatly sorted this out. I need to explain my clapping to them now.
 
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#8 ·
If I may. Actually, it's not a stupid question. The answer is > it was tried. The result was less or same power due (it is believed) to be the nature of how a plat or iridium plug 'creates' the flame kernel (i cannot recall all the detail. sorry). the key is the electrode size, and is the reason they have to use rare earths (heat and wear). There is a vid on the net (somewhere) using a highspeed camera that shows the diffs. I have no idea where it is though anymore.
This is an area with a lot of conjecture. If you find the vid, watch and make your own conclusions.
 
#6 ·
Sorry if this is a dumb question but is that gapping recommendation applied to all of the plugs including the AR103?
 
#11 ·
http://www.nology.com/silver.html

All this sparkplug talk, recently, jogged my memory regarding SILVER spark plugs.

SIlver is the best conductor- bar none.
Opinions????
To be truthful, gold is the best conductor for electronic components, but who can afford gold core spark plugs. Plus they would not last long in their true form. The problem with silver, it is a soft metal like gold and could burn out quicker. Not saying they are worthless, but I would go with copper before silver any day. That is if I did not put the OEMs in it.

I have 100,000+ on my 08, with the original plugs. Time for a tune up soon.
 
#19 ·
Okay, I'll bite. I've seen posts here that say no gain in a stock engine, others say there is a gain from the coppers gapped at .055. My engine is bone stock, no tune, nothing; was that the baseline for the dyno pulls that showed the ~ 5 hp gain? I've got no problem with going to a 103 (colder) plug, used to do it all the time as I tend to drive "enthusiastically" and my parts guys already think I'm crazy and will sell my whatever I ask for.
 
#24 ·
Ok, so even if silver is the best conductor, we can all agree that the cost of such plugs would make plats and iridiums look like pennies on the dollar and way out of 99% of our cost ranges for plugs. True?

130k on stock plugs. My change will be to 103s.
 
#25 ·
Ok, so even if silver is the best conductor, we can all agree that the cost of such plugs would make plats and iridiums look like pennies on the dollar and way out of 99% of our cost ranges for plugs. True?.
False.. ANywhere from 8-15$ a plug- and NOlogy isn't the only one marketing silver electrode plugs. In the Goog search below, I spotted Bosch on the first page of search results.

Wasn't an earlier post quoting 18$ a plug at the dealer for some plat Motorcrafft ? I could be off by a few bucks, and it might have been in another thread- ther's been a spate of "sparky" threads in the past couple of days. The price of Ag plugs is below that- the "pennies on the dollar" (by comparison )is just not r valid.

ANyway, this is a good thread, not everyone needs Ag plugs. There is such a thing as bang for the buck regarding HP and mileage. But ,if the goal is to get all you can get out of the engine( and it seems like there's a few on this board with that goal) it is an option to consider.

My goal, presently, is to keep the skinny pedal steady, and stretch out as long as possible my visits to the gods of petroleum distillates.

http://www.briskracing.com/product.php?productid=48

http://www.google.com/search?source...rlz=1T4ADFA_enUS368US368&q=silver+spark+plugs
 
#26 ·
I take it billie pretty much quoted from the nology and brisk ads...
The plugs liquid tagged are available easily, most likely within a couple miles of peoples homes, unlike ordering and waiting many days.
there was another company that came on here touting their plugs and what they had done on the bench and that they outdo anything... pretty much fell flat on their face when it came to dyno comparison, they slightly outdid stock (IIRC 1HP), while the 103s decimated both.
unless there is real world side by side tests, dont believe the designer hype about their ratings (most are bench tests where there is no actual load or heat stresses on the plug).
That is unless you like having sunshine blown up your butt.
 
#27 ·
I take it billie pretty much quoted from the nology and brisk ads...

Nope, I quoted from no links. I provided links to back up my statements regarding conductivity, resistivity, and thermal conductance, though. Had I quoted from any website you would have seen """""""""""""""""" with writing in between the ""'s.

You can check any text on electronics, physics, WIKI ,or Google "best electrical conductor". Let me help you....
http://www.google.com/search?source...ADFA_enUS368US368&q=best+electrical+conductor

Or talk to anyone involved in semiconductor manf/ packaging
 
#30 · (Edited by Moderator)
loco said:
While your at it, why not explain to them about the heat cycling and erosion properties in different metals under combustion properties. explain to them what annealing means in metallurgy.
Metallurgy in electronics is completely different than in a combustive environment.
Annealing basically softens metal. I only offerred up the semiconductor analog, because, if it wasn't the best conductor, manf's would use something different.
 
#35 ·
Sorry, when changing plugs becomes more than changing my own oil, rationally I need to go to a cheaper plug. Regardless of how soon they need changed.
 
#36 · (Edited by Moderator)
As for the Metal Society text being out of date, I will admit it's old.

I was not aware that there's a new type of silver compared to 50 years ago, -and that is not the best conductor of heat or electricity.
My apologies for not knowing that old knowledge is not worth knowing.

So , to my detractors, where's info refuting anything I've said. Please show me the error in my thinking. If Cu is a better conductor than Ag, surely there must be a link, so that we can correct Google, Wiki, the entire semiconductor industry and the American Society for Metals- which reminds me- in what latter edition of that voluminous text( It takes up 2 feet of my bookshelf) are the obviously incorrect properties of silver corrected and in which they hail Cu as the best conductor?.
 
#37 ·
Well, since Tungsten has the highest melting point, it doesn't mean all steel should be made with it.
Similarly, even if silver is the best conductor, doesn't mean it should be used for all applications.

Thanks again to wicked for the great info on page 1.
 
#40 ·
Thanks to Wicked for some really good information about spark plugs.

You've been on this forum for long enough, you should know by now that any thread on spark plugs will end up like this. There is simply too much half-science information out there on the subject, and too many theories and marketing without independent dynos to back up the claims. It's confusing to everyone. Even TurboTom's dyno tests were done on AR plugs, not A or AP plugs, and the gain was 4 hp not 5.

Your heat range information was mostly correct, although the reason colder plugs work better has more to do with low quality fuel and the high compression of our engines than the spark plugs themselves. Lower heat range plugs produce more power on low octane fuel because spark knock is decreased, timing is not pulled, and therefore you get more power.

There's also a difference you barely scraped on about what the short length of the back-strap. I'm only mentioning that because there are so many things that make up a good plug, or make more power out of a plug. Multi back-strap plugs, for example, are marketed as producing multiple sparks, but this doesn't jive with basic electrical theory of seeking the path of least resistance. What it does is offer more than one resistive path so that if one path becomes more resistant, spark goes to the lower resistant path. That would make these plugs more reliable in the long term.

Finally, nobody has mentioned that the actual conductor at the tip of every spark plug is neither copper nor silver in any case. It's always the same- a nickel/iron alloy. The difference is in the core itself. On the platinum/iridium side, most platinum plugs are copper core plugs with coated tips/back-straps. In a few cases, a small point of p/i is the center conductor. This offers a more reliable sparking point in the situation where fouling is reduced because of the metal used at the tip.

Now if everyone would please stop trying to make points that have already been made and sway everyone to your specific opinion. It's completely pointless and no e-thug is going to learn anything from another e-thug. It just ends up in horribly childish banter that doesn't promote anything but wasted bits on the server. I can't clean it up and delete everything that doesn't agree with the OP because that's a violation of free speech. Everyone has a right to their opinion, and everyone has a right to not change that opinion if they don't wish to.

The bottom line is that spark plugs are very important, and horribly misunderstood most of the time because there are so many factors besides the actual makeup of the plug. Companies out there who want to make a buck abuse this lack of general knowledge by promoting science half based in verifiable facts.

So who's going to start an oil thread now?
 
#41 ·
I would be interested to know about the heat range 'debate?'. SPECIFICALLY > IF you run 103's (A103's, AR103's). Has anyone in this (prob) select group ever suffered fouling?
I recognize it could be an issue, but in a real world scenario does it really occur?
I ask only in that I have read that I should not run the AR103 due to stated concerns (by whynotthinkwhynot and others). But I have never read about anyone ever actually suffering from this. So on a scale of 1 to 10 (1 being almost never), what are the chances normal street cars would have a problem running the cooler 103?

Thanks much! [cheers]
Add > Not to get ahead of myself. IF a cooler plug is used. Would the tune need to be changed to take advantage?
 
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