spark plugs

[Shimian]

Ok, if i stick to Denso, will the Iridium Power IK20L be ok for FD2?

cheers

[SeverAMV]

Spark plug heat range has no effect on when they fire hence NO EFFECT on when the fuel will ignite. Heat range is only about the temperature of the spark plug tip.

heat range doesnt affect when it will fire, but can cause misfire, the tip is often where the mixture makes a fair bit of contact with when the af mixture enters the cylinder. sparkies at too high a temp for too long can cause preignition and hence detonation, which is why we change to diff temp range in the spark plug, which is also why changing to a lower temp range can fix pinging.

spark plugs have to be of the correct temperature range so they can spread the right amount of heat at the right time to ignite the entire mixture. if the spark is too weak, you'll find that most of the mixture wont ignite as easily, and will ignite later, despite ignition timing.

if this werent true, then why isnt everyone just running the lowest temperature range available?

[aaronng]

heat range doesnt affect when it will fire, but can cause misfire, the tip is often where the mixture makes a fair bit of contact with when the af mixture enters the cylinder. sparkies at too high a temp for too long can cause preignition and hence detonation, which is why we change to diff temp range in the spark plug, which is also why changing to a lower temp range can fix pinging.

spark plugs have to be of the correct temperature range so they can spread the right amount of heat at the right time to ignite the entire mixture. if the spark is too weak, you'll find that most of the mixture wont ignite as easily, and will ignite later, despite ignition timing.

if this werent true, then why isnt everyone just running the lowest temperature range available?

Not true. Spark strength does not depend on heat. The reason why everyone doesn't run the lowest temperature is because if the spark plug tip is not hot enough, you will get deposits on the tip.

[SeverAMV]

Not true. Spark strength does not depend on heat. The reason why everyone doesn't run the lowest temperature is because if the spark plug tip is not hot enough, you will get deposits on the tip.

rawr, my email notification tells me you originally posted timing. i didnt mean the spark plug misfires, i meant that the heat of the plug can cause premature ignition.

true that spark strength does not depend on heat, but heat helps spread the flame quicker, even if only a little bit. and spark plug tip not being hot enough isnt the only reason you'll get deposit on tips, spark strength being too weak can cause it as well, as can running too rich.

[RtN]

If you get the correct spark plug i.e BKR6EIX-11 for my EM1.. aren't they pre-gapped to my specific need? Just plug and play isn't it?

By EuroDude

Just get the stock sparkplugs from honda designed for your car. If you want ones that last longer or perform better, make sure you buy the correct size and heat range, and ensure the spark gap is measured properly using a gap gauge to the specs honda recommend.

[dsp26]

If you get the correct spark plug i.e BKR6EIX-11 for my EM1.. aren't they pre-gapped to my specific need? Just plug and play isn't it?

no.. the 11 at the end depicst a 1.1mm gap.. afaik B series is supposed to be 0.9mm??

but who cares, i tell everyone its fine.. i've run the oem coil up to 1.3mm no probs on various loads, ambient temp (summer) and gearing

[EuroDude]

lol so many conflicting theories.. Wiki ftw http://en.wikipedia.org/wiki/Spark_plug


Heat range:
-------------------------------------------------

The operating temperature of a spark plug is the actual physical temperature at the tip of the spark plug within the running engine. This is determined by a number of factors, but primarily the actual temperature within the combustion chamber. There is no direct relationship between the actual operating temperature of the spark plug and spark voltage. However, the level of torque currently being produced by the engine will strongly influence spark plug operating temperature because the maximum temperature and pressure occurs when the engine is operating near peak torque output (torque and RPM directly determine the power output). The temperature of the insulator responds to the thermal conditions it is exposed to in the combustion chamber but not vice versa. If the tip of the spark plug is too hot it can cause pre-ignition leading to detonation/knocking and damage may occur. If it is too cold, electrically conductive deposits may form on the insulator causing a loss of spark energy or the actual shorting-out of the spark current.

A spark plug is said to be "hot" if it is a better heat insulator, keeping more heat in the tip of the spark plug. A spark plug is said to be "cold" if it can conduct more heat out of the spark plug tip and lower the tip's temperature. Whether a spark plug is "hot" or "cold" is known as the heat range of the spark plug. The heat range of a spark plug is typically specified as a number, with some manufacturers using ascending numbers for hotter plugs and others doing the opposite, using ascending numbers for colder plugs.

The heat range of a spark plug (i.e. in scientific terms its thermal conductivity characteristics) is affected by the construction of the spark plug: the types of materials used, the length of insulator and the surface area of the plug exposed within the combustion chamber. For normal use, the selection of a spark plug heat range is a balance between keeping the tip hot enough at idle to prevent fouling and cold enough at maximum power to prevent pre-ignition leading to engine knocking. By examining "hotter" and "cooler" spark plugs of the same manufacturer side by side, the principle involved can be very clearly seen; the cooler plugs have more substantial ceramic insulators filling the gap between the center electrode and the shell, effectively carrying off the heat, while the hotter plugs have less ceramic material, so that the tip is more isolated from the body of the plug and retains heat better.

Heat from the combustion chamber escapes through the exhaust gases, the side walls of the cylinder and the spark plug itself. The heat range of a spark plug has only a minute effect on combustion chamber and overall engine temperature. A cold plug will not materially cool down an engine's running temperature. (Too hot of a plug may, however, indirectly lead to a runaway pre-ignition condition that can increase engine temperature.) Rather, the main effect of a "hot" or "cold" plug is to affect the temperature of the tip of the spark plug.

It was common before the modern era of computerized fuel injection to specify at least a couple of different heat ranges for plugs for an automobile engine; a hotter plug for cars which were mostly driven mildly around the city, and a colder plug for sustained high speed highway use. This practice has, however, largely become obsolete now that cars' fuel/air mixtures and cylinder temperatures are maintained within a narrow range, for purposes of limiting emissions. Racing engines, however, still benefit from picking a proper plug heat range. Very old racing engines will sometimes have two sets of plugs, one just for starting and another to be installed once the engine is warmed up, for actually driving the car.




The main issues with spark plug gaps are:
-------------------------------------------------

* narrow-gap risk: spark might be too weak/small to ignite fuel;
* narrow-gap benefit: plug always fires on each cycle;
* wide-gap risk: plug might not fire, or miss at high speeds;
* wide-gap benefit: spark is strong for a clean burn.

[dsp26]

Eurodude.. part you highlighted in bold makes sense.

Sooo... we all know that running too rich fouls plugs and the O2 sensor also evident from that statement.. so we can agree that octane booster has nothing to do with fouling plugs....

FastFwd: in your case it seems more like a tuning issue as from your description there was no proof or proven discovery that the plugs were fouled.. it seems to me that your car was tuned maybe specifically on 98oct hence it not running correctly on the 95 with oct booster?

[dsp26]

However one thing it didn't cover which is what i'm curious on... thermal conductivity is mentioned, but what about electrical conductivity of the electrode depending on the temp of the ceramic insulator?

Look at Water and oil temp sensors.. their merely solid pieces of metal that increase/decrease the voltage going through them depending on temp... it in turn modifies the return signal/voltage back to ecu/guages...

[Limbo]

fouling generally come from your car running rich.

FF - i know your car is boosted and that would mean that your can was tuned for a specific octane rating. Boosted cars are also running generally richer, to ensure it does not deontate, so end of the day excess richness of fuel is killing your plugs. The higher octane is only increasing it. I think your's is specific to your car, that's why no-one else has experienced it.

If you got your car tuned with those plugs you should be fine

[aaronng]

However one thing it didn't cover which is what i'm curious on... thermal conductivity is mentioned, but what about electrical conductivity of the electrode depending on the temp of the ceramic insulator?

Look at Water and oil temp sensors.. their merely solid pieces of metal that increase/decrease the voltage going through them depending on temp... it in turn modifies the return signal/voltage back to ecu/guages...

Temperature sensors use a thermocouple. The electrode is a full conductor.

[aaronng]

no.. the 11 at the end depicst a 1.1mm gap.. afaik B series is supposed to be 0.9mm??

but who cares, i tell everyone its fine.. i've run the oem coil up to 1.3mm no probs on various loads, ambient temp (summer) and gearing

Depends on the engine, but NGK's website says 1.1mm for the EM1.