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The Ubiquitous Jimmy V.
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Discussion Starter · #1 ·
I am confused :confused:
With 13 to 14 lbs boost..What Plug and What Heat Range.

I tried different Plugs with different gaps..What are your experiances??



jim v.
 

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Pushrod Dinosaur
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Yo JV!!

here's my 2 centz....... with a 2.8 pulley i was running TR-6's @.036 and they worked great. I have NGK BR7EFS #1094 @ .036 in there now, which are one step colder. Checked them for fouling at 300 miles and they looked fine. Gonna check em in another few hundred and if they are ok, im going go to Denso IT-22's (the same heat range as the BR7's). Some ppl are running the IT-20's but Denso finally responded to my e-mail and said that at 14-16 lbs, the 22's are the right plug. I wasn't sure about the heat range so I tried these BR7's before i spent 80.00 on plugs. Both of the NGK's idled fine BTW, i have read that the BR7 fouled with lots of stop and go driving but i haven't experienced any yet. Hope this helps.

gary
 

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The Ubiquitous Jimmy V.
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Discussion Starter · #3 ·
SVTyballz said:
Yo JV!!

here's my 2 centz....... with a 2.8 pulley i was running TR-6's @.036 and they worked great. I have NGK BR7EFS #1094 @ .036 in there now, which are one step colder. Checked them for fouling at 300 miles and they looked fine. Gonna check em in another few hundred and if they are ok, im going go to Denso IT-22's (the same heat range as the BR7's). Some ppl are running the IT-20's but Denso finally responded to my e-mail and said that at 14-16 lbs, the 22's are the right plug. I wasn't sure about the heat range so I tried these BR7's before i spent 80.00 on plugs. Both of the NGK's idled fine BTW, i have read that the BR7 fouled with lots of stop and go driving but i haven't experienced any yet. Hope this helps.

gary
Thank's ,,I am in same situation. The tr6's did fine.. I have a feeling my denso it 20's are too hot.I had a bad tank of fuel and got detonation with the denso's.

jim v.
 

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I am getting ready to install the Denso IT22's in my car as soon as we get some better weather around here.I am seeing 16 pounds of boost with my setup currently.

Matt
 

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What about when you up the boost?? I have the NGK TR-6's now with the Eaton.

When I put the AutoRotor in (SOOOOOOON), should I change plugs? Are there better for bigger boost applications?
 

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The Ubiquitous Jimmy V.
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Discussion Starter · #6 ·
When I put the AutoRotor

??? what's an Autorotor??

jim v.
 

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Jim Vaccaro said:
When I put the AutoRotor

??? what's an Autorotor??

jim v.
Autorotor is the oldest manufacturer of the twin-screw supercharger. Kenne Bell is the US distributor for Autorotor.
 

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The Ubiquitous Jimmy V.
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Discussion Starter · #8 ·
HAMMER said:
Autorotor is the oldest manufacturer of the twin-screw supercharger. Kenne Bell is the US distributor for Autorotor.
Thank's Rich..another Q...What is the Works Blower??

jim v.
 

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HIGH ROLLER said:
I am getting ready to install the Denso IT22's in my car as soon as we get some better weather around here.I am seeing 16 pounds of boost with my setup currently.

Matt
Mine are sitting waiting for a warm day - should be in the 60's here Sunday - IT22's we will see. My car is not pullied. Yet.
 

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Just some more input, U want a non plat plug, like a awsfa22c
awsfa12c, or rquiv. NO platinum, It goes by boost ! I use a 12c
heat range, Its cold, but at 22lbs its fine color good, I little verry little bucking , Surging, Verry slight. If the Denso is plat. dont use
peace Jim u may want to use a 22c or ngk.tr6
 

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nitrous pete said:
Just some more input, U want a non plat plug, like a awsfa22c
awsfa12c, or rquiv. NO platinum, It goes by boost ! I use a 12c
heat range, Its cold, but at 22lbs its fine color good, I little verry little bucking , Surging, Verry slight. If the Denso is plat. dont use
peace Jim u may want to use a 22c or ngk.tr6
Pete,

Aren't the denso's iridium? I was pretty sure they were, and if so, they are actually worse than plat, but as far as I know, the primary difference in plat/copper/iridium is in the size of the tip and melting point. Copper has the widest tip, leading it to "support" boost better due to the fact that when they get too hot and melt the tip, there is a lot of tip left. Plat has a higher melting point and smaller tip, which allows it to resist melting better, but causes more damage to the plug when it does. Iridium is even worse in this regard, with a very tiny tip, but a very high melting point. Again, there is a thread on SVTperformance where I linked to some good docs on this that go into it in much more detail than I have.
 

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If the Iridiums are so bad than tell me why JL & Sal who both are very knowledgeable tuners and are running very high boost levels both highly recommend either the NGK or Denso Iridium plug.From being a past lightning owner i can tell you that anyone running over 15 pounds of boost almost everyone is running either the NGK or Denso Iridiums,the others are using the tr6's until they use the Denso.These plugs are very expensive but you will not get the misfires at top end like you will with the other plugs everyone is experiencing.
 

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Jim Vaccaro said:
Thank's Rich..another Q...What is the Works Blower??

jim v.
Not sure, Jim. I have heard the term before...I think that is what the Saleen blowers are...

But if it's not a positive displacement blower like the roots and autorotor, no one's gonna like it.

Maybe it is positive displacement, I don't know.
 

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yes , i agree . they are worse, copper is the best i think.
as far as other people I dont know,
NetworkingGuru said:
Pete,

Aren't the denso's iridium? I was pretty sure they were, and if so, they are actually worse than plat, but as far as I know, the primary difference in plat/copper/iridium is in the size of the tip and melting point. Copper has the widest tip, leading it to "support" boost better due to the fact that when they get too hot and melt the tip, there is a lot of tip left. Plat has a higher melting point and smaller tip, which allows it to resist melting better, but causes more damage to the plug when it does. Iridium is even worse in this regard, with a very tiny tip, but a very high melting point. Again, there is a thread on SVTperformance where I linked to some good docs on this that go into it in much more detail than I have.
:)
 

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HIGH ROLLER said:
If the Iridiums are so bad than tell me why JL & Sal who both are very knowledgeable tuners and are running very high boost levels both highly recommend either the NGK or Denso Iridium plug.From being a past lightning owner i can tell you that anyone running over 15 pounds of boost almost everyone is running either the NGK or Denso Iridiums,the others are using the tr6's until they use the Denso.These plugs are very expensive but you will not get the misfires at top end like you will with the other plugs everyone is experiencing.
I never said the plat/iridium plugs were bad. WHAT I SAID was that they had more of an issue when the tip did finally melt. Here's a good explanation, copied out of an article I looked up for the previous two plug threads:

The shape of the plug electrode is important. The sharper the electrodes (both of them!) become, the easier it is to ionize the air between them. If I take two smooth brass balls of 3" diameter (like mine ) and put 10,000 Volts across them, I can get a spark to jump when I push them to within about 0.125" of each other. If I take two long, sharp needles pointed at each other, that same 10,000 Volts will still spark when they are 1.5" apart! (For the technically minded: this can easily be seen from Gauss' law if you compare E between the extremes of either two point charges or two equally spaced infinite parallel planes).

There is also another good reason for sharp points: "unshrouding" the spark. Imagine that we put a big flat plate over the tip of the ground electrode, thus shrouding the spark from the combustion chamber. The spark would still happen, and the mixture would probably still ignite, but the burn would have to go out, around the plate, and back in to the center of the combustion chamber, resulting in piston rock and detonation. We'd much prefer that the burn happen in a very smooth, ideally hemispherical manner to produce a smooth pressure curve inside that chamber. By keeping the electrodes sharp, we unshroud the spark as much as possible, allowing the maximum contact between the spark and the air/fuel mixture, making it ignite more easily and the burn spread more smoothly.

So it would seem that the sharper the electrodes, the better. This would be true except for two caveats having to do with heat. The very hot spark emanates from the electrodes at their tip. If this tip is very sharp, it will get extremely hot because there is so little metal to heat and there is not enough area to conduct that heat away. Think of it this way - if you unbend a paperclip and hold it's tip in a blowtorch, the tip will glow red hot in seconds, but you'll still be able to hold the relatively cool end. Now take a short piece of rebar and do the same thing. Long before the rebar gets red hot, you will have dropped it and will be sucking your thumb to quell the big, burned blister that is popping up. Why? Because the rebar had lots of metal volume to heat and plenty of area to conduct that heat to your hand, whereas the paperclip had neither. So the paperclip end got much much hotter in much less time. The paperclip is like a sharp tip and the rebar is like a fat tip (if you didn't get that already).

So, the caveats:
Caveat number one: Too sharp a tip will melt the electrode. If the temperature of the tip reaches the melting point of the metal that it's made of - you can kiss it goodbye. Here are the melting points of some commonly used metals (Celsius):
Zinc == 420
Aluminum == 660
Copper == 1083
Steel == 1400-1500
Platinum == 1772
Iridium == 2410
This problem is mainly concerned with the volume of metal at the spark tip - if the temperature even instantaneously reaches the melting point, some of that metal will disappear. You can see that Platinum and Iridium coated plugs can withstand significantly higher temperatures, and thus can have sharper tips than their steel or copper counterparts. To add insult to injury, if some of the metal does disappear from a very sharp tip, then you've actually opened up the spark gap some. To prevent that from happening, we have to start with a wider tip, such that any small amount that is eroded will not change the size or geometry of the tip by too much.

Caveat number two: Too sharp a tip will create a "hot spot" in the combustion chamber. Even if you don't reach the melting point of the metal, you can still get it glowing hot. If that tip is still glowing red hot when the next compression stroke comes about (two full engine revolutions since the last spark) that residual heat can actually ignite the air/fuel mixture before the spark is supposed to occur. This is pre-ignition. It generally creates even more heat - leaving the spark plug even hotter than the last time thus repeating the cycle until you melt a piston. Ouch!

To avoid this, we want a wide area near the tip to conduct as much heat away from the tip as possible. Here are some of the thermal conductivities of some commonly used metals (Watts / centimeter*Kelvin) :
Zinc == 1.16
Aluminum == 2.37
Copper == 4.01
Steel == 0.70 - 0.82
Platinum == 0.716
Iridium == 1.47

From the following article: http://www.automotivearticles.com/get.php?action=getarticle&articleid=18

Cliff Notes:

Copper uses a "dull" tip, which doesn't ignite the A/F mixture as well, and produces a less powerfull spark. Copper also has a lower melting point, meaning that the tips melt faster under high heat. However, since the spark isn't as "hot" due to the dull tip, this lower melting point isn't as much of an issue as it could be. The dull tip also means that melting a bit off of the tip doesn't cause as many problems (like increased gap) as it would for a smaller tip. Plat has a smaller tip than copper, and a higher melting point, meaning that it produces a more powerful spark, a more efficient burn, and higher temps. Unfortunately, the small tip also means that when some does burn away, it causes the gap to widen more than copper. Finally, Iridium takes all of the benefits and disadvantages of plat to the next level. What's the best? Depends on what you need.
 

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HAMMER said:
Thanks for the education, Network man.

:D :D

Very informative technical write-up.
NP Hammer :) I just try to help when I can with my limited automotive knowledge. :D Running no chip, plugsare something I had to play with a bit....
 

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NetworkingGuru said:
NP Hammer :) I just try to help when I can with my limited automotive knowledge. :D Running no chip, plugsare something I had to play with a bit....
Great article!!

What a/f #s are you running with your mods and no chip? Those mods should make scary a/f #s without a chip.

Now for my question. I am running CAI, 9" K&N, 2.93, tuned chip, and cat back. I have the stock plugs (AGSF22FM1) gapped at the factory setings of ..044 So far I have not detected any detonation issues on the dyno or street. From what I have read in this post I either should see a problem or will have a problem.

I have another set of the AGSF22FM1s gapped at .038 to put in as soon as I get chance. Which I am doing just as a precaution from the posts I have read.

FYI I have been running the stock belt, but just put a 74 Gatorback on and haven't had chance to run it. I saw 13.9 lbs of boost on the dyno (which dropped to 11 at higher rpms) with the stock belt.
 

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trmn8r said:
Great article!!

What a/f #s are you running with your mods and no chip? Those mods should make scary a/f #s without a chip.

Now for my question. I am running CAI, 9" K&N, 2.93, tuned chip, and cat back. I have the stock plugs (AGSF22FM1) gapped at the factory setings of ..044 So far I have not detected any detonation issues on the dyno or street. From what I have read in this post I either should see a problem or will have a problem.

I have another set of the AGSF22FM1s gapped at .038 to put in as soon as I get chance. Which I am doing just as a precaution from the posts I have read.

FYI I have been running the stock belt, but just put a 74 Gatorback on and haven't had chance to run it. I saw 13.9 lbs of boost on the dyno (which dropped to 11 at higher rpms) with the stock belt.
Trmn8r,

My A/F is scary until about 3K, then it goes from OK to optimal. I was getting light detonation with the stock plugs (detectable as a small crack on the tip of the leanest plug after about 500 miles), due to the plugs being too hot (pink porcellin). I swapped them out with the 12FM1's gapped at .038, and the plugs look perfect.

As for your car, I would take a look at the plugs, and if they look fine, I'd leave them. I would imagine that the 22's might have some slight pink in the rear banks in your case, but I can't see it being much worse than that.

Belt wise, I put on the 74.5 Gatorback a day after the pulley swap because I smelled the stock belt burning when I got on it. However, I measured both belts, and my stocker was 74.5 as well. I don't smell my new one slipping, however, so I guess it's an improvement.
 
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