A question for tuners or anyone using these plugs.
Are they any good?
I read that they are prone to damage when detonation occurs but is that the fault of the plug or incorrect set up of the fueling system? Basically the car needs to be tuned properly as I understand it.
Any comments please?
Cheers
Simon
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hi,,sorry for the ignorance,,,
can you confirm what you mean???
surely they all detonate??
every time the piston compress's the gas it detonates???
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To light a (stoichiometric) petrol-air mixture under pressure, such as with a medium to large amount of throttle in use, is easy, in as much as the plug-gap/spark-length can be quite small. However, when you throttle back and get to low cylinder pressures and mixtures that are polluted by the remains of the previous burn, due to less than perfect scavenging, it is a different story. You need the large gap, as specified, because the the mixture is difficult to light and the electrodes are dipping into the initiating fireball and can quench it if too close.
Detonation occurs when the flame is well advanced and the iniating spark will have no effect, other than lighting the mixture, or not lighting it. It does not occur with low throttle settings so spark quality is not a factor.
The penalty of needing a large plug gap (for low throttle) is the higher voltage you need to spark the plug when on full compression and that is where the ignition will flash over if it has a weakness.
Plugs need to run hot enough to stay clean without being so hot as to cause pre-ignition. I don't know the plugs you mention. But if they get damaged by detonation, I assume they have thin electrodes.
Thin ones have some possible advantage with low throttle uses in lighting poor mixtures but as the existing plug gaps have taken that into account with the engine in question, I would be a bit sceptical of actually getting it. You will notice it only when pussyfooting along at 25 mph or so in top on the level!
Unless there is something odd, like you have changed the car's specification, my view is you will not get an improved performance by deviating from the manufacturer's plug specification. In the past we have been through phases of offerings like surface discharge plugs and the like. Unreliability was a feature and none made it to the production models.
Many years ago, for a couple of years, I was part of a small team in an automotive research establishment and did a lot of study on the spark ignition of petrol-air mixtures and built and tested and compared ignition systems. Way before electronics got seriously into motor cars.
A specially equipped car was used that could change instantly from one system to another. The car was well instrumented with an accelerometer etc.
A lot of gas-ignition research had already been done and written up by the US Bureau of Mines and I expect it is still there for any who want to read it.
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I wouldn't bother with the expense, I remember BOSCH Platinums when they cam out in the early 1980s used to suffer from breaking of the centre electrode and it's ceramic insulator. They too were of s very thin wire and insulator design.
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You don't get low cylinder pressures when throttling back. Unless there is something seriously wrong with the engine the cylinder pressures should be the same whatever the throttle position or engine speed.
As for the original question - sva eyour money. I've tried all these fancy multi-electrode plugs and found no measurable difference in performance or economy.
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\"Nothing less than 8 cylinders will do\"
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You don't get low cylinder pressures when throttling back. Unless there is something seriously wrong with the engine the cylinder pressures should be the same whatever the throttle position or engine speed.
What can I say in the face such lack of knowledge? You have a different petrol engine to everyone else then.
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maybe he has a mazda rotary engine ??? :)
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You don't get low cylinder pressures when throttling back. Unless there is something seriously wrong with the engine the cylinder pressures should be the same whatever the throttle position or engine speed.
Eh?? Ever heard of 'engine braking'?
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You don't get low cylinder pressures
The engine is economical on parts. No accelerator/throttle needed.
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ANYWAY,,,back to the question,,,are they any good,,do they have ANY benefits???
and what happens to the spark plug tip,if it falls off???
and if the answer is what i think it will be!!! do we get to sue the spark plug makers???!!!???!!!
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Can't answer specifically about Denso Iridium plugs, but I have now had the NGK Iridium IX spark plugs fitted to both my Corolla and Beetle and are very pleased with them - performance does seem a bit better, and fuel consumption was noticeably better on the Beetle (had Bosch Platinums).
However, I have read reports on the Internet about problems with the Denso Iridium plugs, specifically them breaking after installation....
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I've always stayed with NGK's. Use some of their Iridiums at the moment - no probs at all. I get them at a good price (about £6-7 each).
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ahh,,,more like it
so what we are saying is,,,,,,IRIDIUM plugs are very good,,and do what they say on the box....
but the DENSO version of the IRIDIUM plugs arn't as good???
is this it??
or are we saying that IRIDIUM plugs are no good?????
cause i want to believe that they are fab!!!
and i wanna get some,,so aid my engine..i have read that they use LESS power to produce the same spark!!
there fore freeing up power for elsewhere!!
agreed?
or still over hyped..and stick with the original spark plugs???
what a good topic this is!
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If you can get a thin electrode plug that is robust. By that I mean the thin electrode does not burn away with the heat and the discharge, and it has the right heat rating for your engine,it does have potential advantage over the standard one in being able to light the petrol mixture more easily. Because there is less metal shrouding the sparked fireball.
Having looked at an NGK picture the plug does looks robust with its tapered down centre electrode. It all depends on the wear/life of that in terms of it burning away. However, since aprilia has used them and found them OK, they should be worth a try.
www.ngksparkplugs.com/products/cars_trucks_suvs/ir...2
0&country=US
Under full power the voltage to spark them should be less than the thick electrode ones (spikes breakdown easier) and that will reduce the voltage stress on the coil insulation.
As for therefore freeing up power for elsewhere that makes no sense. The energy in the spark and burn time, roughly about 1 milli-second, depending on the burn voltage, is dictated by the coil inductance and design. The coil discharges itself into the plug.
Incidently, dont believe all the extra bits as told to you by the non-technical spark plug saleman.
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only repeating what is on their web site,,,and b4 you say,,,dont believe all you read.......these multinational companies have legal obligations customer service realations and their credibilities to uphold,,,so they arnt gonna lie on the web sites,,,all they do is tell the truth from their perspective,,rather than your perspective
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Of course I've heard of engine braking! Engine braking is caused by high pressure not low pressure.
Low pressure on throttling back does not happen. If it does then there must be a leak somewhere surely?
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\"Nothing less than 8 cylinders will do\"
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Of course I've heard of engine braking! Engine braking is caused by high pressure not low pressure. Low pressure on throttling back does not happen. If it does then there must be a leak somewhere surely? -- \"Nothing less than 8 cylinders will do\"
This leaves me speechless. Are you trying to re-write the laws of physics?
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Why does that surprise me! You seem to disagree with everyone on technical issues.
Tell me this - If you connect a compression tester to a cylinder, does the pressure vary with the speed you turn the engine over at? No is the answer.
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\"Nothing less than 8 cylinders will do\"
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Cant say I agree. asumming engine on overun. draws the same amount of air less fuel injected.means engine still gets same air pressure. less fuel intake.says braking power increases please correct I didnt go to uni.Though wish i had
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Steve
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i think u lot have hi jacked this topic...
go away and get back to the other topic u were in..this is about spark plugs
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You are right, but here goes--
When a piston descends, it creates alow pressure above it which allows the atmospheric pressure to "push" air into the cylinder. Except under certain conditions the cylinder never fills completely on full throttle. Between the cylinder and the outside air, apart from valves, is the throttle plate. This plate is controlled by the driver. On full throttle it is arranged to give as little obstruction as possible to the air. At tickover or on the over-run, it is arranged to allow either no or a minimum of air, at tickover for example, just enough to allow the engine to overcome the small load on it.
If you go into over-run, then with the plate closed, the piston has to "pull" the air against a closed tube. It therefore cannot "pull" much. This means that the engine, in effect, is acting as a vacuum pump. The amount of air/fuel is not enough to run the engine at the speed it is going. The "deficit" is the engine "braking" effect.
The amount of fuel is kept proportional to the amount of air. If air is reduced then fuel is as well to avoid a lean mixture.
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:)
oh well,,it does make good reading.....
and yes,,my engine does help to brake the car,,"engine braking"
mine has it so does everyone!!!!
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