I have 17k miles on my Evo. I pulled 2 plugs which are iridium plugs to see how worn they are. Looks like they need replacing. I should be putting down around 330 to the wheels. My question is is it time for a colder plug? If so can someone give me the part number for the NGK plugs?

 

i dont know the part number

but there
NGK 7s

u can get them from AMS

 

7s are stock heat range. 8s are one step cooler.

http://lancershop.com/customer/produ...7&cat=0&page=1

 

so 8 would be a good choice? ^^

 

Not a bad idea. Gapped to .026.

 

So should I change to 8s then?

 

Denso's iridiums are good plugs. IKH24 for Evo 9 and IK24#4 for Evo 8.

 

or you could go just a half step colder with NGK BR7ES. Gapped to around .022
Just try both and see which yields you better results.

 

you should go one step colder for every 100 hp over stock. so for your application you are probably better off with the ngk bpr7es or the half step colder br7es.

 

Im looking to replace with iridium plugs though since thats what came stock

 

Is this standard practice across the Evo community? This is a good tip I haven't read yet.

 

I usually go with a colder plug after 75 more horsepower. It's good practice on turbo cars since more boost equals more heat blah blah blah.

 

i have 333whp, didnt like the way the engine idled on brp8es, went back to br7es, much better.

 

there is no specific formula to how much additonal horsepower you should running over stock to install colder plugs. some say after additional 100 hp or like speed corps says 75hp. it depends on your specific car, mods, gas, boost, tune, etc. when you do start making 75-100hp over stock it may be time to go a half step to a full step colder in plugs.

 

I think Im just going to go with a half step colder. Does NGK make iridium plugs that are a half step colder then my original iridium plugs? It looks like it only goes a full step colder.