How to choose the best spark plug. TECH

[WeaponX_Perf]

Hey everyone, I realize I am the new guy here so let me introduce myself. I am the owner and lead engineer of WeaponX Performance. WeaponX designs and produces equipment with the latest technology to ensure our customers get the most state of the art equipment to date. This along with a never ending R&D program ensures our equipment gets updated as new technology is introduced.

I thought I would jump in here and make a technical thread on spark plug design to educate the public on different designs as well as answer any questions anybody might have about this subject. I think the more everybody learns about this the more they can make an educated decision on which spark plug is superior in design and function for their application.

I thought I would start with one of the more important aspects of spark plug design.

INTERNAL RESISTANCE
Back in the 60's Champion introduced a spark plug with internal resistance. This was because they had found that the ignition system on vehicles back in the day would create noise in the radio system. The adverse effect of this is that the internal resistance spark plug dropped power output of the spark plug. Today we still use the same archaic spark plug design even though electronics and electronic devices have much better noise suppression techniques that no longer require the use of a resistor spark plug. Today the only device usually affected by a non resistor spark plug is a radar detector. Radios and other electronic devices usually have built in noise suppression techniques that DO NOT require the use of a resistance style spark plug.

So how much power is dropped through the use of a resistance style spark plug?
Federal noise emissions guidelines specify to spark plug manufacturers that all street oriented vehicles must use a resistor style spark plug. This means Denso, NGK, Champion etc must design spark plugs for sale on street oriented vehicles to include a 5,000-10,000 ohm internal resistance. WeaponX does not have to follow these guidelines since these spark plugs are advertised as race only, but they work equally as well on a street oriented vehicle.

All that being said our K6CF, K7CF and K8CF spark plugs all use an oxygen free highly conductive copper core with an Iridium / Rhodium fine wire electrode design where our competitors use a poor conducting carbon core with their Iridium fine wire design. I will explain more in the future about why we use an Iridium / Rhodium alloy tip. Typically these spark plugs display anywhere from 0.9 to 5.9 ohms of internal resistance.

So back to the main question, just how much power is lost because of the resistor. Well lets take a real world example. In the picture below the NGK spark plug measures 4.96k/ohms or 4960 ohms and ours measures 5.6 ohms. Using ohms law we can calculate the voltage loss at the resistor in the spark plug. Take a look at the attached pictures. These are examples of resistances in the ignition circuit including the plug wire and the spark gap. There are some other variables such as actual spark gap resistance and inductance but for our purpose this will give everyone a good idea of the power lost in the ignition circuit due to a standard resistor spark plug.

Notice in the supplied example a typical resistor spark plug circuit outputs only 2 amps of energy where the WeaponX spark plug in the same circuit doubles (over 4 amps) the available amperage in the ignition circuit.

Not only this but a resistor spark plug has a drop of over 11,000 volts of energy! The WeaponX spark plug in the same circuit only drops 23 volts of energy!

This means in this example while in the SAME circuit, with the SAME ignition there is an extra 11,000 volts of energy with 2 more amps of power. Total wattage increase is 22,000 watts of energy from spark plug to spark plug! This is a very substantial difference in power output.
This is only one of the main points and we will post more information on the designs and differences in the future but for the time being if anybody has any question please feel free to participate and ask any questions on the subject.

[third_shift|studios]

for a good read, and fellow sponsor!

[Spaz]

damn good read!!!

[WeaponX_Perf]

ok, i'll be the noob who asks:

what makes 1 plug better than the rest? Does it fire hotter? burn cleaner? Where is the the difference noticable? Only in dyno or mpg's? Or can you actually rev faster with better plugs? Will you really feel a difference between 2 performance plugs?

This is actually from another thread but thought this thread would be more appropriate for a long winded response.

It comes from here.
http://www.ls1.com/forums/showthread.php?t=91146&page=2

To answer fully the first is the resistance. As you can see in the post above amperage in the ignition circuit can double and voltage increases at the spark gap.

How does this make it better?

With more voltage at the spark gap the gap itself can be opened up more then a typical spark plug. As everybody knows the bigger the gap the greater the potential power output. This, in practice doesn't always hold true though.

If I use less energy to start a spark (with a smaller gap) then the spark duration ends up being longer in time. So, even at the same gap, with our spark plugs the burn time goes from an average of 22 degrees of crankshaft rotation at our test conditions to 30 degrees of crankshaft rotation at the same spark gap with just a spark plug swap. This means the spark is lit for 30% longer then an average spark plug meaning a more complete combustion process. This also means the spark is more intense then before.

Does it burn cleaner and are the differences noticeable?

Yes, because the spark duration increases the engine lights off potential "mis-fires" more readily meaning more power, more performance, more mileage and crisper throttle response.


Does it increase power and mpg?

Because the air fuel mixture is lit off better the benefits make themselves known in mpg and power. Customers have reported as much as a 3MPG increase in fuel mileage and considerable amount of RWHP.

Will you really notice a difference?

Our very first LS1 customer came to our shop and we installed the plugs as a "test". The customer swore up and down we changed something other then the spark plugs but it was a direct before and after. If memory serves he was running the TR55's. He claimed throttle response was much crisper, power was better and has just recently reported a fuel mileage increase of 30 extra miles to the tank. The before and after seat of the pants feel was definitely there. He was actually one person that directed me to this site.

for a good read, and fellow sponsor!

damn good read!!!

Thanks guys!
I'll have more tech for everybody soon. The more you guys know the better.

[Sarge]

So if I embrace this theory....say I had a spark plug that produce a kabillion volts I would make a linear amount of RWHP? There is only so much fuel/air/compression to work with....at what voltage/gap is maximum or peak power made? There is a curve. I understand marketing and butt dyno statements. MSD has some really good tech papers on the subject......wide gaps/voltage/resistance versus multiple spark etc. Welcome by the way.

[WeaponX_Perf]

So if I embrace this theory....say I had a spark plug that produce a kabillion volts I would make a linear amount of RWHP? There is only so much fuel/air/compression to work with....at what voltage/gap is maximum or peak power made? There is a curve. I understand marketing and butt dyno statements. MSD has some really good tech papers on the subject......wide gaps/voltage/resistance versus multiple spark etc. Welcome by the way.

Got you.

First thing is that the spark plug does not produce voltage, it merely conducts energy from the ignition coils to the spark gap. The internal resistor wastes energy and diminishes it through heat generation. This is what in essence "supresses" noise. The adverse effect to the internal resistance is that it is harder on your ignition coils and there is a reduction in overall power available at the spark gap.

I will post our tech paper information which also shows ignitability potential through the reduction of resistance and the modification of the spark plug electrode. This is probably what you are after and I will have it all for you guys here in this thread tomorrow. If you want a quick rundown there is a quick whitepaper on our website. http://www.weaponxperformance.com under the spark plug section.

There are curves that show diminishing returns when it comes to some design parameters on the spark plug. Resistance is not one of them. The curve is very linear. As resistance drops, ignitability potential increases when the source energy stays the same.

Hope that clears things up a bit for the time being and thanks for the welcome.

[Sarge]

LOL....yeah I know a plug doesn't produce but conducts....my bad....I wasn't clear.....but I still struggle after all the plug "claims" over the years....PulStar etc. etc. that all come back to the same point.....0 resistance.... does not equal more or less RWHP .....many factors outside of plugs come into play and I am soliciting from you why your plugs are different than the many others that preceded you in this claim.

[WeaponX_Perf]

LOL....yeah I know a plug doesn't produce but conducts....my bad....I wasn't clear.....but I still struggle after all the plug "claims" over the years....PulStar etc. etc. that all come back to the same point.....0 resistance.... does not equal more or less RWHP .....many factors outside of plugs come into play and I am soliciting from you why your plugs are different than the many others that preceded you in this claim.

Totally understood. I know exactly where you are coming from and don't take offense to any of this. There are allot of other manufacturers that make some outrageous claims when it comes to spark plug designs so it's understood that there will be some scepticim and this is the reason I am here right now. It's advantageous to let everyone know the testing and engineering done in order to release a spark plug that actually performs better.

Of course you are right that the power level return is not linear with less resistance but the ignitability level is much greater with 0 resistance. I'll explain more in depth when I have an hour or so to write something more thorough.

[hamburger68]

well, from my understanding of the internal combustion engine, the perfect plug would be the one that produces a spark that lights an optimal burn and produces little or no misfire due to short or weak / too cold spark. above that, there's no gain in horsepower to expect.
with that said, i know the value of a good spark plug find this to be a really interesting thread, learned a lot already.

[Sarge]

Totally understood. I know exactly where you are coming from and don't take offense to any of this. There are allot of other manufacturers that make some outrageous claims when it comes to spark plug designs so it's understood that there will be some scepticim and this is the reason I am here right now. It's advantageous to let everyone know the testing and engineering done in order to release a spark plug that actually performs better.

Of course you are right that the power level return is not linear with less resistance but the ignitability level is much greater with 0 resistance. I'll explain more in depth when I have an hour or so to write something more thorough.

I appreciate that......Old dogs can learn but them sum bitches are not trusting of anybody
Here is where my head is......
You only have so much fuel/air to compress and light off. the A/F mixture is pre determined so it doesnt change.
The combustion is set so that doesn't change.
So the "trick is to get your 14.8 A/F compressed to 10.5:1 to burn completely....in other words no unburnt fuel/air when the exhaust valve opens.
So we open up the gap of a plug to get a wider spark area.....or we utilize multiple firing coils.....and we are tuned to the 9's. I need to understand how a low/zero resistant plug will gain RWHP or any advantage over a properly tuned engine running a properly operating ignition system as described. Myself I have over 600 RWHP ( all motor and I aint alone here on this forum ) and get 25MPG cruising on the highway......now that is performance/efficiency at its best....Having been under a shade tree for over 30 years and having a peice of paper on the wall telling folks I sat in classes for a few years....I just fail to understand claims of increased performance and excellent butt dyno returns on anything other than a engine with worn out plugs/wires/tune getting a fresh set....of any type of plug.
I also see on your website you guys sell and recommend NGK's for your performance ignition parts......look forward to it.....

[hamburger68]

^^^ that's what i meant! only couldn't write it in that very detailed and elaborate way.

[Too Fast]

I appreciate that......Old dogs can learn but them sum bitches are not trusting of anybody
Here is where my head is......
You only have so much fuel/air to compress and light off. the A/F mixture is pre determined so it doesnt change.
The combustion is set so that doesn't change.
So the "trick is to get your 14.8 A/F compressed to 10.5:1 to burn completely....in other words no unburnt fuel/air when the exhaust valve opens.
So we open up the gap of a plug to get a wider spark area.....or we utilize multiple firing coils.....and we are tuned to the 9's. I need to understand how a low/zero resistant plug will gain RWHP or any advantage over a properly tuned engine running a properly operating ignition system as described. Myself I have over 600 RWHP ( all motor and I aint alone here on this forum ) and get 25MPG cruising on the highway......now that is performance/efficiency at its best....Having been under a shade tree for over 30 years and having a peice of paper on the wall telling folks I sat in classes for a few years....I just fail to understand claims of increased performance and excellent butt dyno returns on anything other than a engine with worn out plugs/wires/tune getting a fresh set....of any type of plug.
I also see on your website you guys sell and recommend NGK's for your performance ignition parts......look forward to it.....

That is what I have found out in my few years on this planet also. If the engine is not running bad already, how can a simple spark plug give your engine more power, if the combustion chamber is already optimized.

[Hot Black Trans-Am]

This is all very interesting.

[WeaponX_Perf]

I appreciate that......Old dogs can learn but them sum bitches are not trusting of anybody
Here is where my head is......
You only have so much fuel/air to compress and light off. the A/F mixture is pre determined so it doesnt change.
The combustion is set so that doesn't change.
So the "trick is to get your 14.8 A/F compressed to 10.5:1 to burn completely....in other words no unburnt fuel/air when the exhaust valve opens.
So we open up the gap of a plug to get a wider spark area.....or we utilize multiple firing coils.....and we are tuned to the 9's. I need to understand how a low/zero resistant plug will gain RWHP or any advantage over a properly tuned engine running a properly operating ignition system as described. Myself I have over 600 RWHP ( all motor and I aint alone here on this forum ) and get 25MPG cruising on the highway......now that is performance/efficiency at its best....Having been under a shade tree for over 30 years and having a peice of paper on the wall telling folks I sat in classes for a few years....I just fail to understand claims of increased performance and excellent butt dyno returns on anything other than a engine with worn out plugs/wires/tune getting a fresh set....of any type of plug.
I also see on your website you guys sell and recommend NGK's for your performance ignition parts......look forward to it.....

To be quite honest, on the bench the NGK has a very poor spark and I usually recommend Autolites or the BOSCH super over the NGK stuff after benching all of them. Take it for what it's worth. There are however certain circumstances where some of our vendors and customers don't want to spend the money or are die hard NGK copper plug "forever" individuals so we try to accomidate them as much as possible. That being said, the people that have listened to our recommendations usually end up with much better results then not.

As far as lighting off the A/F mix can I ask you. How long does it take for the A/F mix to properly reach the spark kernel and will the spark kernel still be lit when it does make it to the spark plug? Is every combustion stroke the same? I think we can agree that every stroke is different and so is the time frame for the A/F to hit the spark gap. That being said....

From personal experience we have seen systems light off for as little as 3 degrees of crankshaft rotation and show very poor drivability characteristics. This phenomenon can commonly be seen in CDI modules. The reason CDI's multi-spark is not because of improved performance but because when the spark kernel is only lit for 3 degrees of crankshaft rotation it doesn't always fire off the air fuel mixture making for the occasional misfire event. So in essence all the multi-spark does is give increased performance through reduction of mis-fire events. Also, the reason CDI's are not used on street vehicles with emissions is because of this very fact. Misfires will cause a vehicle to quickly fail an emissions test. Now can I ask you... If they know it's missing at low rpm what do you think will happen at higher rpm, with no multi-spark? If a couple misfire events happen, you would never feel it, but the fact of the matter is that it does happen.

On the other hand an inductive ignition system with smart coils can light off the air fuel mixture for ~20-30 degrees of continuous crankshaft rotation. Why do OEM's use inductive ignitions instead of CDI's when CDI's output 3 times the ignition energy? You would think that the CDI would be superior but since the inductive ignition has a longer spark, which lights off the A/F more reliably, it is the system of choice. Now ask yourself, would it be possible that a spark plug which allows more energy output and has a longer duration spark to light off more potential mis-fire events then another plug that eliminates that energy through heat and has a shorter spark duration? The answer is obvious.

That is what I have found out in my few years on this planet also. If the engine is not running bad already, how can a simple spark plug give your engine more power, if the combustion chamber is already optimized.

Keep in mind that OEM's, not tuners, not joe blow garage tech, but the people that design your engine specify a platinum fine wire spark plug. I can tell you first hand that the dyno operators and engine management calibrators TUNED YOUR ENGINE with something that isn't a copper spark plug. I will also tell you that by altering the dynamics of such WILL have an effect on your power level and tune. Infact there are some old cars that run like crap with a fine wire spark plug and this is because of this very reason.

When you say optimized, it was optimized with a fine wire design and your stepping into a copper. Is it still optimized?

Also, stock ignition systems are designed to output the proper amount of energy for stock levels of power. May I ask you... do you upgrade injectors? Of course you do, you want an optimal injector for the horsepower output. The last thing you want to do is bump fuel pressure to make a 19lb injector work for your app. That being said you CAN do it but would it be optimal? You can use a street style resistive spark plug but is it optimal for improved power output on a higher hp engine?

[0verkill]

I appreciate that......Old dogs can learn but them sum bitches are not trusting of anybody
Here is where my head is......
You only have so much fuel/air to compress and light off. the A/F mixture is pre determined so it doesnt change.
The combustion is set so that doesn't change.
So the "trick is to get your 14.8 A/F compressed to 10.5:1 to burn completely....in other words no unburnt fuel/air when the exhaust valve opens.
So we open up the gap of a plug to get a wider spark area.....or we utilize multiple firing coils.....and we are tuned to the 9's. I need to understand how a low/zero resistant plug will gain RWHP or any advantage over a properly tuned engine running a properly operating ignition system as described. Myself I have over 600 RWHP ( all motor and I aint alone here on this forum ) and get 25MPG cruising on the highway......now that is performance/efficiency at its best....Having been under a shade tree for over 30 years and having a peice of paper on the wall telling folks I sat in classes for a few years....I just fail to understand claims of increased performance and excellent butt dyno returns on anything other than a engine with worn out plugs/wires/tune getting a fresh set....of any type of plug.
I also see on your website you guys sell and recommend NGK's for your performance ignition parts......look forward to it.....

same thing i would like to know. like i asked in a difrent tread on tv the other day thay tested a standerd plug and one of the e3 plugs and got more power and beter mpg. i dont know plugs. thanks for all the info from evrey one thou

[Sarge]

To be quite honest, on the bench the NGK has a very poor spark and I usually recommend Autolites or the BOSCH super over the NGK stuff after benching all of them. Take it for what it's worth. There are however certain circumstances where some of our vendors and customers don't want to spend the money or are die hard NGK copper plug "forever" individuals so we try to accomidate them as much as possible. That being said, the people that have listened to our recommendations usually end up with much better results then not.

As far as lighting off the A/F mix can I ask you. How long does it take for the A/F mix to properly reach the spark kernel and will the spark kernel still be lit when it does make it to the spark plug? Is every combustion stroke the same? I think we can agree that every stroke is different and so is the time frame for the A/F to hit the spark gap. That being said....

From personal experience we have seen systems light off for as little as 3 degrees of crankshaft rotation and show very poor drivability characteristics. This phenomenon can commonly be seen in CDI modules. The reason CDI's multi-spark is not because of improved performance but because when the spark kernel is only lit for 3 degrees of crankshaft rotation it doesn't always fire off the air fuel mixture making for the occasional misfire event. So in essence all the multi-spark does is give increased performance through reduction of mis-fire events. Also, the reason CDI's are not used on street vehicles with emissions is because of this very fact. Misfires will cause a vehicle to quickly fail an emissions test. Now can I ask you... If they know it's missing at low rpm what do you think will happen at higher rpm, with no multi-spark? If a couple misfire events happen, you would never feel it, but the fact of the matter is that it does happen.

On the other hand an inductive ignition system with smart coils can light off the air fuel mixture for ~20-30 degrees of continuous crankshaft rotation. Why do OEM's use inductive ignitions instead of CDI's when CDI's output 3 times the ignition energy? You would think that the CDI would be superior but since the inductive ignition has a longer spark, which lights off the A/F more reliably, it is the system of choice. Now ask yourself, would it be possible that a spark plug which allows more energy output and has a longer duration spark to light off more potential mis-fire events then another plug that eliminates that energy through heat and has a shorter spark duration? The answer is obvious.




Keep in mind that OEM's, not tuners, not joe blow garage tech, but the people that design your engine specify a platinum fine wire spark plug. I can tell you first hand that the dyno operators and engine management calibrators TUNED YOUR ENGINE with something that isn't a copper spark plug. I will also tell you that by altering the dynamics of such WILL have an effect on your power level and tune. Infact there are some old cars that run like crap with a fine wire spark plug and this is because of this very reason.

When you say optimized, it was optimized with a fine wire design and your stepping into a copper. Is it still optimized?

Also, stock ignition systems are designed to output the proper amount of energy for stock levels of power. May I ask you... do you upgrade injectors? Of course you do, you want an optimal injector for the horsepower output. The last thing you want to do is bump fuel pressure to make a 19lb injector work for your app. That being said you CAN do it but would it be optimal? You can use a street style resistive spark plug but is it optimal for improved power output on a higher hp engine?

Well we still are not getting to the meat here....you are describing timing and knock retard etc based on various inputs such as air temp/MAF signaling etc. This will control the spark. Most of high performance riders have SD Tunes and we control/tune when and where the spark occurs. NASCAR far and away ( 800+RWHP) run Champion plugs. My car did not come with platinum plugs....2004 GTO....I do not doubt your belief in these things....but I am trying ( bear with me) to understand your rational to make a claim of additional RWHP by swapping plugs in a optimally tuned LSX motor. I understand timing and fail to see how if the timing is off your plugs would correct a cylinder firing at a few degrees of erroneus timing.....frankly my concern over what you describe is detonation.....a plug is only going to fire when it is "told" to fire and only fire for the cycle it is "told" to cycle.

[WeaponX_Perf]

0 resistance.... does not equal more or less RWHP .....many factors outside of plugs come into play

Back to this.

As I have previously explained there is a change when allowing more energy and a longer duration spark to enter the combustion chamber. Also, to clarify, every vehicle does not respond the same to resistance changes so there is no magical graph for this. The lower resistance doesn't always mean proportionally more power based on combustion chamber design, cylinder fill rate, engine efficiency, piston design, crevis volume and some other parameters. What it does do, without a doubt is improve cylinder ignitability.

IGNITABILITY POTENTIAL


Ignitability is a measure of how effectively and efficiently a spark plug can ignite the air fuel mixture in the combustion chamber. The best way to measure ignitability is to lean out the air/fuel mixture until misfire occurs. This is because lean mixtures are difficult to ignite. This gives engineers an indication of which spark tip style will gives better overall ignitability characteristics. These characteristics allow spark plugs to perform better under normal operation. The end result is more power, lower emissions and higher efficiency of the ignition system. Spark plugs with a smaller center electrode diameter and a lower resistance offer better ignitability results. (image attached)

As you can see the fine wire designs can ignite an A/F mixture as high as 17.3:1 where an equivlant copper design can only ignite a mixture as lean as 15.1:1 with the same test conditions. Also, a standard spark plug's center electrode of 2.5mm diameter has more than 15 times the surface area of a fine wire center electrode. You can see that moving from a standard 2.5mm electrode plug to a fine wire plug results in a dramatic improvement in ignitability.

In back to back comparisons of a 0.4 / 0.5 and 0.6 tip diameter the voltage required to fire the spark plug are all almost identical. Only when you take a spark plug with a common size center electrode (such as a copper or standard style spark plug) does the voltage requirement increase to a point where there is a compromise in power output. (image attached)

In addition, electrons are emitted where the electrical field strength is greatest, this is from wherever the radius of curvature of the surface is smallest, for example, from a sharp point or edge. It would be easiest to pull electrons from a pointed electrode but a pointed electrode would erode after only a few seconds. Instead, the electrons emit from the sharp edges of the end of the electrode and as these edges erode, the spark becomes weaker and less reliable. If electricity prefers to jump from a smaller edge which spark plug design would be considered superior? Copper simply cannot be made smaller because of it's poor resistance to erosion. The Iridium design wins in 2 areas. The voltage requirement for Iridium is much less and the electrode can withstand erosion due to it being a harder alloy.

[Sarge]

SWRI found the same thing....I'll find their paper for you......but the conclusion was/is to properly gap your plug and more results were derived from tuning, plug gap and coil voltage than a plug design or material used to manufactuer.....yes many here run Iridium plugs....Your charts reflect a power to gap differential....in extremes that really do not translate to the LSX world......you will not get any questions nor arguments from me about the end results of "tuning" your gap....we all do..... .035 to .050 gaps deliver different results for sure....
I enjoy these discussions very much and appreciate your time and effort to share.....
I gotta go to a meeting ( lawyers suck) and will pick it up later this afteernoon....maybe get one of the engineers from SWRI to join in....

[WeaponX_Perf]

SWRI found the same thing....I'll find their paper for you......but the conclusion was/is to properly gap your plug and more results were derived from tuning, plug gap and coil voltage than a plug design or material used to manufactuer.....yes many here run Iridium plugs....

There is a major flaw with this statement. The ignition coil does step up voltage BUT spark plug design and electrode gap is what dictates overall spark voltage. With the same ignition coil and 2 different spark plugs there will be a different power requirement to start the spark and to sustain the spark. This is non debatable for anybody that truly knows ignitions. This is also highly reflected in the charts provided. As I stated before, the more energy required to start the spark means less overall spark duration at the gap. As a side thought, to prove my point even further, I can also supply a 10,000 ohm spark plug to Mr. Lous. If he is willing to test those as well.

Your charts reflect a power to gap differential....in extremes that really do not translate to the LSX world......you will not get any questions nor arguments from me about the end results of "tuning" your gap....we all do..... .035 to .050 gaps deliver different results for sure....
I enjoy these discussions very much and appreciate your time and effort to share.....
I gotta go to a meeting ( lawyers suck) and will pick it up later this afteernoon....maybe get one of the engineers from SWRI to join in....

I have to disagree, they translate quite well for the LSX world. How exactly do you find they don't? Test conditions are suppose to measure extremes, not nominals.

[0verkill]

im with sarge on this one i dont see how your plug would make more power in a lsx engine, mabe a carbed set up but with a computer it will just cange the setings to get the tuned af ratio any way. i dont know mabe im just geting lost