Robert56

iTrader: (2)

What you have to realise is the fact that on the spray the cly pressures can skyrocket which equals heat. Now when you have a tiny diameter electrode (material doesn't matter) that is in a projected tip, then the chances of it heating up to glowing hot become a reality. Then the blow torch effect comes into play. Hey, if ya guys are determined to run these plugs on the giggle gas, be my guest, but problems my arise, and that's why NGK does not rec this plug for nitrous application. If you don't believe me do your research over at NGK's site, it's spelled out in black and white what plugs for what use, check the racing plugs.
Robert

brad8266

iTrader: (23)

I didnt even see that it said dont use for nitrous, lol. If they say no, then i aint trying it. My copper tr6's work like a charm anyway.

Nick@HSW

iTrader: (4)

With all do respect to those involved I’m going to have to disagree with most of which is being said. Iridium gets a very bad rap from people that have little to no experience with the material itself. Most of the time people see the electrode and automatically assume since it is thin and narrow it cannot withstand heat. This is simply not true. First what one needs to realize is that the center electrodes primary duty is not to absorb heat and dissipate that energy. This is the primary function of the insulator, threads, head etc. Does this mean that the center electrode does not get hot, no, but its primary function is not to dissipate heat. 90% of the time the reason for a plug failure is incorrect heat range selection, gappage, over-useage, air quality or other mechanical failures. I can honestly say I have never pulled a plug to see the center electrode melted, its normally the ground strap that fails first. Second, it all does come down to the material. We’re talking about thermodynamics…how can you not take into consideration what type of material it is? That would be like a civil not taking into account the weight of the bridge itself while calculating load capability. The melting point for each of these materials is completely different. Iridium is at 4471*F and Copper is at 1984.32*F. Another key item to look at for the materials is heat of fusion. This is the amount of heat absorbed by a unit mass at its melting point in order to induce phase change. The higher this number the more energy required to phase change the solid to a liquid. Copper is 13.05kJ/mol and Iridium is 26.1kJ/mol. I really think that speaks for itself.
I also think the easiest way to illustrate this would be to take a look at fourier’s law.

-Qdot = -kA(dT/L)
Where Qdot is heat transfer per unit time
k = thermal conductivity of the material********
A = heat transfer area
dT = difference in temperature across material
L = material thickness*********

For simplicity sake lets concentrate on the two factors that are of concern in this thread. Material and thickness. What drives this equation is mostly that anyways. k for copper is 398 W/m K @ 225*C and iridium is 147 W/m K @ 225*C. What this, along with heat of fusion, illustrates most is the ability for a material to carry a smaller L to obtain sufficient qdot. Its simple physics really…if a material has this innate ability to displace energy, why can’t it be a smaller diameter? Why not take advantage of spark quality by utilizing an exotic material that allows for a smaller electrode?

Now please do not take this the wrong way…in no way am I saying a is better than b, because I’m not. I’m simply stating facts of material. I read by someone that if you were to heat up a x” thick piece of steel vs. a xx” thick steel which will hold up longer. In my opinion that proves nothing except for that particular material (steel) L matters. You’re taking two items of the same exact material! If you were to take a xx” thick piece of copper vs. a x” thick piece of iridium and super heat them to 1800*F I will tell you what the outcome will be and its all proven right above. I guess I just want people to see some factual information concerning the materials and let them judge for themselves what is better and I hope nobody sees this as an attack on other peoples opinions. Because its not, everyone is entitled to their own beliefs. I will state this though. Our shop truck routinely sees 15lbs of boost and two stages of nitrous. The plugs that reside in this motor are Denso Iridiums (which happen to have the finest thickness electrode of the bunch) and cylinder temperatures become outrageously high very quickly with the complex nature and behavior of forced induction and nitrous. The addition of this plug allowed me to run a larger gap without blow out, have a great idle quality and while our plug changes are just as frequent as copper, the plugs appear to be in better fashion. So just to initiate some friendly conversation I ask prove to me why Iridium is a poor choice in a nitrous application? Food for thought…and I’m hungry.

On a side note, I would not consider longevity to be the best quality of Iridium…I would have to say the improved spark control and energy consumption are the two leading benefits.

Nick

TwoFast4Lv

iTrader: (8)

well I stand corrected.

Still not going to use them Seems like every time We see a hurt engine it had the latest and greatest plug's. IF you are lucky they just took out the vavle seats and burned a valve. I might try a set on our twin turbo shop truck but I figure on rebuilding that engine again soon after anyways

CAT3

iTrader: (9)

I cant recall seeing any damaged engines, from nitrous use, using anything other than NGK TR-6 (or colder) plugs. Hell, I melted all 8, yep, everyone of them, but I sustained ZERO engine damage. Whereas my buddy melted one TR-6 and chunked his head and block. I am sure your not incorrect, I can only imagine the numerous failures and other than TR6 plugs, but I am also confident the overwhelming majority, at least in the LS1 community, will be using TR6.

Nick, good info there, glad someone has the technical knowledge to explain things. I used them, and would again. I also seen the "back it up with science/fact" bullshit coming. More times than not products are bashed, or rejected by people who never used them. Hell, if fear were the reason not to use something new, where would we be?

blacktransam

iTrader: (13)

i have run iridiums in my car since i started spraying.. 150 on the heat range 6 and 200-250 on PUMPGAS 93 octane.. and the heat range 7's..

with a heat range 7 plug in my car i would foul the coppers out in about 2000 miles of daily driving.. i'm at 8k miles on this set of irridiums and pulled the last set at 10k..

they are all i will run.. when i called ngk and asked that was there recomendation..

mike

brad8266

iTrader: (23)

Thanks nick for priving my points.

Robert56

iTrader: (2)

I still contend, which nick never addressed, that projected tip plugs are not great nitrous plugs, period. The NGK irdium in question does state what thay are rec for, not what they are not rec for. If you do a little research at their site you will see that the rec racing plugs for nitrous are non projected tip, and as far as I could find, non iridium. can someone find a projected tip plug, that has a center electrode tip that is of iridium that NGK rec for nitrous?
Matt has some good stuff on the heat thing, but still the fact that a glowing center electrode out in the middle of the combustion chamber is less than optimum spraying nitrous, maybe not to bad on small hits, but over all not the way to go. My point on the irdiums was the small diameter will heat up quicker, not that it isn't a better coper of heat compared to copper. When I said heat a 1'4 stock to a 14 gauge, the point was which will heat up easier and quicker, not which could withstand prolonged heat. So, in conclusion, some good tech from many, and much to mull over for all. Hey, some guys run 200rwhp shots on 91 octane gas and no problems, does this make it optimum cause they had no issues?
Robert

V6 Bird

iTrader: (15)

Just because everyone is spraying or running big boost on TR6's doesnt make them the brightest light buld in the group. If everyone jumped off a cliff, would you follow suit. i sure the hell wouldnt put my motor through a projected tip spark plug catastrophe!

If you out to make any kind of power, you run a non-prokjected tip plug. If you want fuel economy and idle like a caddy, you run projected tips. Which group do you fit?

V6 Bird

iTrader: (15)

dumb choice.

brad8266

iTrader: (23)

Sine I stated that I use the non-projected TR6's you make that decision, try reading everything before you open your mouth smartass.

02 Pewter LS1

iTrader: (8)

I run this plug in my car with no problems and it has a better idle than the TR6 for my car. I really like the TR6IX plugs I would recommend them but I only spray a baby 100 shot.

Robert56

iTrader: (2)

Well on a 100 shot you can run the stock projected plugs if you feel lucky, and many have. A buddy in his Z06 ran a 11.47 100hp dry with stock plugs and gap, so it can be done, but the point here, is it done the optimum way, no.
Robert

Nick@HSW

iTrader: (4)

I apologize, I was not aware that the whole conversation was about projected tips vs. non projected. I assumed that iridium was in question, which it still appears to be with your reply which I’ll get to later. Can I ask this…what plugs do you run in your car now? If I remember correctly you’re spraying quite a bit on a projected tip TR6, no? And they were very decent results. So why question something that is currently working great in your car along with 99.99999999% of the LSx’s on this board? I’m not saying that to inhibit technological growth, I’m just curious is all.

Concerning nobody offering a racing iridium plug…Denso offers numerous resisted iridium racing spark plugs that have non-projected tips. They offer quite a few different firing end constructions to suit any need. I have a feeling NGK is going to follow suit in the near future perhaps even playing around with some titanium. But again, I think that the concern for using these plugs rests with the guys spraying large amounts of nitrous.

I hope I understand where you’re coming from so I can fully engage this question, so let me run this by you first…you’re saying that since both the tr6 and tr6ix are projected tips that the tr6ix is more susceptible to heating up quicker because of its thinner center electrode, correct so far? And you’re using the example of two thickness’ of stock that are heated at the same rate to show that the thinner piece will heat more quickly than the thicker, yes no? If this is correct so far, what I think you’re failing to fully understand is the nature of the beast itself. Yes the thinner piece of stock will heat more rapidly because L is far smaller, BUT you’re still comparing the same material so the metallurgic properties are identical in the equation. Iridium is far different than most metals. Its hard, brittle and withstands a tremendous amount of heat. What I don’t think that you’re seeing exactly what you’re comparing. Again, take a 20 thousandths thick piece of iridium and a 100 thousandths thick piece of copper superheat them and see which heats “quicker”. I guarantee you’ll be surprised by the results…when you can compensate L with k. And again, the concern really isn’t with the center electrode. The problem lies with the ground strap. When a projected tip plug is made, they need to extend the ground strap out along with the center electrode. The ground strap then becomes the weak link on the plug. I hope this makes sense and again this isn’t meant to be any sort of personal attack, just trying to feed some info.

brad8266

iTrader: (23)

EDIT:foot in mouth.

brad8266

iTrader: (23)

nevermind

Robert56

iTrader: (2)

Nick, correct, I run the standard tr6, however, the size of shot I am running now this will be changing to a true nitrous plug. Look at how many have turned their plugs (tr6) into a blow torch on this forum, we see it all the time in pics. I believe the projected tip is a fault, and the begining of the end when an issue arises. Meaning, say it's a hot day and your motor is running hot, you max timing without kr, well this day things come together and cause a little detination, now you have a glowing red hot projected tip (whether electrode and/or strap) what happens, the blow torch effect and pieces soon come loose and go through engine. This is why, imo, projected tips are not great for nitrous. Most of the irdium tipped electrodes I have seen are rec for turbo and blower applications, but not nitrous, and there must be a reason?
Lets say the iridium electrode gets red hot but holds together, then you have a high overlap cam, well now you have a ignition source at the wrong time, and when a mix of fuel and nitrous meet this ignition source at the wrong time you could be looking at a serious repair bill, whereas the copper would have allready blown apart and went through engine, maybe doing damage, maybe not. Preignition on a nitrous car can/is devastating and can easly melt a piston down at it's easiest damage scenerio. Nick, I never once took anything you said as a slam, but rather a nice addition to a civil tech talk that everyone has had good input. Are any of us plug engineers, no, so none of us are absolute know it alls on the subject and can learn from this talk. I know I have picked up a few facts to add to my knowledge base.
Robert

brad8266

iTrader: (23)

I picked up some too.

BTW, I am an Internet spark plug engineer so i know what Im talking about.

Robert56

iTrader: (2)

Yea, we see this often, "Internet Engineers", and if ya heard it on the web it must be true.


That's why I started this thread, I thought about the projected tip iridium being the end all plug for the lt1's on the spray and it just didn't seem correct. Mostly it was a "Internet Engineer" in another site pushing is skewed view in a manner that sounded good to most, but sometimes we have to ask questions to find the real facts.
Robert

brad8266

iTrader: (23)

Like the Internet Engineers here that claim that headers will make you run rich, even at idle, regardless of the fact that the PCm will adjust fuel trims to stay at 14.7:1. People just repeat stuff they hear on the net.