How do you know when your car needs colder plugs? Does the fuel charge preignite and create knocks? Or is there just less power in the upper rpms.

 

On the Evo 9 stick with the stock plugs.

 

This!

For most people, it has to do with the horsepower figures. There's more into it though!

 

^^ So the stock plugs will be good for fully built set ups shooting for 500+AWHP as well?

 

A hotter plug will make more power, however it can cause detonation (knock).

If you run to cold of a plug, they will foul quickly as they cannot burn the carbon off of them.

Generally speaking, a hotter plug has a longer electrode and a colder plug has a shorter electrode. When trying to make power, you want to run the hottest plug possible, without causing knock. When shooting for 500 WHP, it's a good idea to put a half a step or a full step colder plug in. An added bonus with a colder plug is that it will also give you more clearance from the piston to the end of the plug.

TLDR; yes colder plugs is a good idea for that kind of power.

That's my .02 anyway.


-Bink

 

Agreed. It seems like running anything but creates more issues than it's worth.

 

I've look for colder plugs and they are super expensive for the 9. Not worth running IMO

 

Doesnt make sense unless your running serious boost, but even then you can just make the gap smaller so it doesnt blow out.

 

I could've sworn I read on here in my searching that running a colder plug was generally a better option on the Evo 9?

I purchased a set to throw in when I get the car tuned... but after reading this I'm reconsidering I guess. I'm only running intake filter (cone), TBE, LICP and UICP and fuel pump and EBCS. Probably won't have the boost up higher than 22psi?

Where's the threshold? I mean... is there some place I can get, or can we put some information in here about when, and why you should run colder plugs?

 

Noted, so running stock plugs gapped to smaller to prevent blow out combined with E85 to prevent knock should be good for 500+ correct? I'm going to do this lol

 

me too because I want the same set up you have

 

Stock plugs on a 9, but on an 8 run colder plugs

 

Really?! NICE!! I wish you the best of luck!

 

Gapping the stock plugs is not recommended. The Iridium material is supposedly very brittle.