any GOOD reason for 2 steps colder plugs?

[Grifter]

Any good reason someone would put plugs that are 2 steps colder in a stock car (other than spray, which i dont THINK this car ever has seen)

when i get a used car, i like to go through it and start everything fresh. new plugs, wires (if applicable), oil, filters, etc. just to get to a point where i know the ages of everything. So i changed the plugs tonite, and found the previous owner had 12c plugs in it. stock are 32 heat range right?

i know from my Mark, that 2 steps colder is more of a hinderance to performance than stock heat range coppers on a stock/bolt on car. so i threw in Autolite 764's (stock heat range copper, eqiv of 32c's)

just wondering if there was a good reason they might have had for colder plugs...

[hitchhiker]

I am aware of some very basic situations, but I am certainly no expert here...

S/C can raise incoming air temp and the colder plugs will help compensate.

Lower octane availability means gas that flashes at a lower temperature and colder plugs can compensate here too.

Advancing timing can trigger knock and again, colder plugs can compensate.

Regards,

Dave

:D

[GarageMahal]

Do a search on 12C and see what you find. Some of the expert vendors here recommend the 12C on naturally aspirated and 22C on supercharged. I can't say I ever figured out exactly why myself but I just put 12C plugs in myself.

jta

[Grifter]

my personal experience is that on a NA car the stock heat range made the most power. when dyno tuning the mark, i swapped the 12c's i had in the car with 764's after a run, it made 3rwhp more. call it a dyno fluke maybe, but the car ran so much better with the stockers in there. so i will see how it runs this morning.


BTW, GarageMahal, nice plates in your sig, i have those on my MM

[GarageMahal]

BTW, GarageMahal, nice plates in your sig, i have those on my MM

I had to order them right after I first saw 'em. They really go well on a Marauder and you can't beat the cause you are supporting :)

jta

[Grifter]

Indeed. I did the same thing. Thankfully they transfer from car to car. I really didnt want these to go with the car i traded in.