dan_uk

hey I think I put the OEM iridium's back in: IFR7G-11KS
I am a little nervous about trying to gap the colder ones to give them another go so I'll probably leave these in

allmotorslut

You're not N/A, you run nitrous lol But do you use theses plug with your nitrous?

ShocK

I ran 1 step colder on my AP1 with a LOT of bolt ons, the car idled like crap unless it was 85+ degrees outside.

wadzii

if your car dosnt run right b/c of a change of one step then you either have other issues or you got a bad plug from the get go.

up or down one heat range will not change anything as far as idle/drivability goes unless the plugs are so cold they foul out very quickly and one step colder is unlikely to cause that

zeroptzero

ignition advance settings being equal, taking heat out of the combustion chamber will reduce power. Heat = power as long as you don't get detonation. It's hard to generalize though unless you know exactly what is going on within the engine. If you remove heat and you get more ignition timing you can make more power. If you remove heat and ignition timing stays the same you will likley lose power. There is a chance that colder plugs can foul easier. I wouldn't bother going colder unless I could do some datalogging to really know what is happening, some dyno testing would help in conjunction with DL.

Gernby

If you study datalogs of stock S2000s with stock plugs, you'd see that the ECU is pulling lots of timing all the time. My brother's stock '06 S2000 runs between 4-9 degrees of knock retard across the whole RPM range. My '08 runs several degrees less knock retard with the colder plugs.

I agree that pulling more heat from the combustion reduces power, but I find it hard to believe that much heat is extracted by the spark plug's electrode in comparison to the cylinder walls. That's why I replaced my stock thermostat with a hotter version.

wadzii

colder plugs dont do alot to take heat away from the combustion chamber, they transfer the heat from the PLUG to the head faster.

IE. the PLUG stays cooler, not the chamber.

its easy to read the heat on a spark plug, so instead of guessing, try a couple of different heat ranges, read the plugs and use what the engine tells you to run. 8's were perfect on my motor.

JuicedS2K

Yea man, i just said N/A cuz i atleast tell myself im N/A untill im spraying lol. But yea i have been using these plugs without and problem with and without the nitrous.

JuicedS2K

Thats awesome to know man, never knew that, thanks.