spark plugs

[SeverAMV]

if you switch to plugs that are too cold, your engine may not start properly and you may actually lose power because the fuel will ignite too late.

but roughly, for every 50-100hp extra your car has over stock, you should go down one temp range (colder plug), or go down if your motor is pinging.

[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.