Can someone explain the need for a hotter or colder plug? What are the pros and the cons

 

hotter plugs for more efficient fuel burn, burn out carbon in cylinders (so i've been told. I'm still using NGKs)

 

I'm really familiar with plug ratings as I raced 2strokes for a long time.
I used to have the charts between Champion and NGK memorized. NGK numbers ascend for colder plugs and Champion descend.
That BP6ES is an NGK number and would be equivalent to, oh, probably an N-11Y Champion (strictly from foggy memory.)
Man, I hope I got that right :-)

My experience has been that NGKs are broader in heat range and more resistant to fouling than Champions. Not enough
experience with any other brand to comment. Other than Bosch Platinums which are junk.
I would think that with modern ignition systems, mass airflow sensors, knock detection sensors and the rest, I wouldn't be surprised
to learn that tweaking the plugs' heat range doesn't get you much of anything any more.

But to answer your question directly I guess I could simply state that if you drive your rig at lower rpm's say aroudn 2000 most of hte time, you can get away with running a hotter plug. If you run your rig around 5 and 6 grand you should run a "colder" plug.
Just a rant from my 2-stroke motocrosser mindset.

Also something else worth mentioning: I think, with unleaded gas, that the ability to "read" your plugs electrode to determine whether it is running to rich or too lean can not be accurately done. Those days ended when leaded gas went unleaded.

 

If i am getting some detonation tho, wouldnt i want to try a colder plug?

 

Year, Model, Engine???

If you have a 22RE you have one choice, OE style NGK or Denso... they dont run properly on anything else.

 

94 22re i have NGK's in it now, I was looking at possibly the denso iridium plugs that have a colder range

 

I would stick to a stock plug, the 22RE doesnt like other plugs. I put Boschs in mine and it wouldnt even run. If your getting detonation its from something else, fix that.. dont correct something else to fix the problem.

 

this olskool method still works on carburated engines, maybe not with EFI? i still use it when i want to tweek my carbs

 

I know I could still read 2 stroke dirtbike motor plugs, while running unleaded. Just with all the computer control affecting modern engines I can't fully believe that you will get any accurate reading off a plug electrode at all. Just my thought.....not sure if I'm right nor not.