People use different intake manifolds (with shorter runners than the Evo) and cams and pistons and head porting on the 4G63T in DSMs, but they almost always use NGK copper plugs because they just work.

 

Just to reverify I check the Service Manual
Pg 16-35
Gapping Standard Value: 0.7-0.8mm (0.028-0.031inch)

 

I would have to dissagree with this statement, according to the manufacturers test data, and the design trend with racing plugs indicate that the opposite is true.

Exactly, irregardless of what type of plug you use, if you select the proper heat range for your application they should all work just as well regarding detonation suppresion.
So a cooler heat range copper plug had less detonation than higher heat range iridium plug, that's hardly an argument against iridium plugs.
Plug heat ranges actually indicate the measured/estimated electrode tip operating temperature. Each manufacturer has there own method for indicating heat ranges so it is difficult directly compare heat ranges. You just need to find the best heat range with a specific manufacturer and plug type for your application.

Maybe because it's not hype? If they do not become fouled irdium plugs will last several times longer than conventional plugs. In the long run you will actually spend less money, time, and effort.
The problem I have with conventional plugs, is that in these high energy(turbo) applications the electrode begins to deteriate very quickly. So while they may work well when first installed they require constant monitoring and regapping to maintan performance. As the electrode tip losses it's sharp edges they become harder to fire, increasing the risk of missfires which can be very damaging to the engine under high boost/RPM.

Yeah, because Mitsu put all sorts of unnecessary, high priced performance components in the EVO

Considering all of the other items we spend money on for high performance the cost plugs (even iridium plugs) is relatively very small. Yet a good spark plug is so critical to proper engine performance. IMO it is not a good place to try and save a couple of dollars, especially when over time the actual savings aren't really there.

 

Clinton "worked" in the White House, but that damn sure doesn't mean he was the best choice. My point is not that your choice in plugs is wrong... it is that for those who really know engines, saying that the engine in the Evo should use the same plugs as any DSM, because the engine is the same, is ignorant. It may, it may not. I highlighted you posting proof of that. The dynamics of the airflow change so does the requirements for the most efficient combustion. Will a million and one combinations work? Of course they can. I wish I had a dollar for every shad tree monkey who pulled 500whp out of a four banger... wish I had ten dollars for every one of those who left a safe 50 to 100whp on the table due to inefficient parts combination, and esp. tuning and component prep...

Again, I'm too old to argue. It's my opinion. Maybe it is the Gov't work, but you got to step back and veiw the "big picture".

 

50 to 100hp isn't going to come out of your spark plug choice. Either it fires or it doesn't. Copper plugs fire, and are cheaper. They do wear out more quickly than iridiums, which is why I change them often. At $8 a set and 10 minutes of labor, it isn't exactly a hardship.

So, after acting all high and mighty in your post regarding "shade-tree monkeys," and talking about the "dynamics of airflow," what exactly have you tuned or prepped?

This is what I have done:
http://www.geocities.com/shaperebuild/

I've run 118mph on a 16G turbo in a full weight 2G Eclipse GSX. You don't do that if you have left out 50 to 100 "safe hp" due to inefficient tuning. Tuning isn't that hard. It is just that you have an entire industry full of tuning shops telling a ton of fanboys that in order to be safe and get the most power, you have to let their shop tune your car. It is a self-perpetuating line of BS.

Screw that. If you built your car, you know it the best. Learn about it and do it yourself and you will make the most of your own car in all conditions. The shop isn't going to be there to tune your car when the temperature drops at the track and you can run more boost than before and make more power. And you know what? 95% of shops out there don't know any more about the "dynamics of airflow" than you or I do. There are precious few people that I would choose to work on porting a head, for instance.

The shape of the DSM and Evo combustion chambers are the same. The bore is the same. The stroke is the same. The head and intake manifold are a better design for sure. But that isn't going to change whether or not a certain spark plug will light off your mixture.

2G DSMs came with a dual ground electrode spark plug called an NGK BPR6EKN. They used dual ground electrodes because they wouldn't wear out as quickly as single electrodes. The platinum (which is not as good a conductor as copper) on the ground electrode of an iridum plug serves the same purpose, to lengthen their life.

Personally, I don't give a crap about how long my spark plugs live. If I get a misfire on the way to work, I'll stop by the local NAPA at lunch, pick up a set of 4 NGK BPR7ES plugs and have them installed a few minutes after I get home.

 

In this case, they put in a set of spark plugs that will last quite a bit longer than a set of copper plugs. But possibly at the cost of some extra knock. This is probably acceptable for the average car owner.

Show me the data that shows that sharp points in the combustion chamber do not promote hot spots and thus detonation.

 

Guys..these are spark plugs we are taling about here...get some perspective!!!

We sell the Iridium for the sheer reason they are easy for us to get, and people ask for them. Are they needed? Nope, I do not think so. A properly running car will be able to run copper NGK's just fine. Have I put Iridiums in a car and been pleasantly surprised - yes sir, absolutely. Does that mean they work magic in every car, or in every Evo...by all means no.

For Iridium's, we always go to one step colder than stock as a matter of course. We do the same with the NGK copper's when we run those.

As for gap, you ALWAYS check the gap before putting it in, regardless if they come "pregapped" or not. It takes less than 5 minutes to do, and saves you (potentially) from doing the same job twice.

 

If your using the same heat range there is no reason (or proof) to indicate that a copper plug will be any more or less prone to detination than an iridium plug? Correct? If no, please show us the test data indicating otherwise.

If your getting detination caused by the iridium stock plug, then go with a cooler iridium plug heat range.


Ok SA show me the proof that it does! My proof is this: Take a look at any plug manufacturers race designed plugs, do they actually have larger blunt tip electrodes? I guess they don't care about smaller sharp point electrodes causing detonation in there customers high compression race motors, huh.

The only reason old style copper electrodes are so much larger is because they break down so fast, larger electrodes take longer to break down.

Tha fact is iridium plugs have several industry established and accepted advantages over old style copper plugs. That is why every manufacturer offers them, and many high end cars are starting to use them.
IMO The time and money you spend trying to run copper plugs more than offsets the initial cost difference, and honestly I do not believe that copper plugs have any added performance benefit, in fact just the opposite appears to be true.

Sure there are a few individuals who have had problems with iridium plugs, but these were hardly controlled testing situations. Under cirtain conditions any spark plug can fail, if anything the iridiums have several characteristics which should allow them to hold up better under adverse conditions.

 

I guess the guy can't see the fact that I'm not arguing the point of the spark plugs... I'm not arguing, or name calling, as it was perceived. I'm simply stating (poorly I guess) that you can't say that X will necessarily work with Y because they are similar. Never did I say X will not work, or work well, as Y. Matter of fact, my point was so far off topic, I probably should have kept it to myself. My retort was was solely in regards to a blanket statement made that the two different engines are the same... Esp. while listing the reasons they are not. I, at no time, stated one was "better" than the other. "High and mighty" are terms best left on SuperHonda. This is a classic example of "my dick" is bigger than your dick" when dick has nothing to do with it. I think ShapeGSX was too quick to be defensive when there was no need. He is one of the more practical people posting here and I respect him for that reason. "Shade tree monkeys" was not directed at him or anyone on this board per se. It was a poor example of the fact that it is easy to make big power these days with a little chunk of money.

Back to the subject. I still maintain that you may pick your poison when it comes to plugs... the NGK coppers work well in many different engines. I'm running them in my 10:1 boosted SC GSR that kicks the **** out of my Evo... a good example? No.

PS I've built a 900hp VR4 but never really cranked out anything special in a 4 cylinder... Now my acid etched stamp is on quite a few Pratt & Whitney’s cranking out over 25,000lbs of thrust... not that it matters...

 

People polish the sharp edges off of pistons and in combustion chambers to keep hot spots from contributing to knock. Why would spark plugs be any different? They are also in the combustion chamber.

If your spark plug fires, it fires. If it doesn't fire, you get a misfire. A different type of spark plug isn't going to give huge benefits in torque or power unless it causes misfires or knock (which would indicate to me that it is a bad choice ).

As for racing plugs, different types of racing have different requirements. Top fuel dragsters don't even use their spark plugs for half the run. They are burnt away and the engine diesels its way to the finish line.

Zeus, sorry for taking your statements wrong. It smelled like an attack, so I somewhat treated it as such.

 

They are different, plugs are self cleaning, piston surfaces are not, plug electrodes are designed to regulate temperatures to induce ignition at the optimum momment. Piston surfaces should not induce ignition, spark plug electrodes on the other hand...

It seems to me that you ideally want the combustion chamber surfaces to maintain even consistant temperatures. I could see how a sharp edge on the piston surface could build up deposits creating hot spots and possibly interrupting flow patterns. I just do not think you can compare that logic to the function of a spark plug.

I am just saying that iridium plugs have some very real well established benifits that justify there additional cost. There is also no proof that they are harmful or perform worse than a standard plug in any way, provided your comparing plugs with identical heat ranges.

In some cases the most expensive option is not alway better, in this case I think it is.

 

I think the first part of your post is one of the most widely neglected areas in rebuilds today. People will run race gas at the drop of a hat, but will throw fresh cut pistons right in an engine with out any attention to "deburing" them... esp. around the valve reliefs. Makes no sense to me what so ever as "deburing" the combustion chamber will have a dramatic effect on lowering the knock count alone. (Steps off soapbox).

...Middle is spot on in layman’s terms...

As to the last, I'm one of those old ****** who's idea of attacking someone is simply to say, "your a dumbass!" as apposed to "crafty linguistics"... of which I have little to none. Hell, if you haven't noticed, I frequently forget the beginning of my sentences before I get to the end of them (probably why my statements unintentionally offended).

To the original poster... use what you can afford right now. That is, the ones suggested here. You can experiment with the cheaper ones as they are cheap. As for the more expensive OE's, well, they have gone 11 seconds...

 

let snot forget NGK also offers tons of their plugs in a pertruding and non pertruding version as well..I ahve played with both on one of my own cars, and have found pretty significant differences...not sure if they do it for the Evo or not though

 

You gotta love typos.
Sorry adam couldn't resist.

 

Cool my P&W makes 29000lbs thrust .. hmm .. yours is 5 stage turbo vs my 8 stage ??

Maybe I can use the ignitors from the augmentor section ??

Viper driver ??