how often are you suppose to change the plugs on evo 9? i changed my plugs last summer to one step colder plugs from denso, and recently im getting break outs on wot again. any info would be great thanks

 

What exact plugs are you currently running?

 

I have 18k miles of 50/50 leaded fuel and still haven't replaced the stockers. I think iridiums should be good for at least 50k miles.

But if you need new plugs EBAY seems to have the best prices for both Denso and NGK.

 

Yeah, Iridium plugs are good for hella miles.

 

Honestly -

I change mine every 3,000 miles when I change my oil.

I run NGKBPR7ES. They are cheap and offer better detonation protection than iridium plugs.

The reason I change them that often is my car is not my DD and when the Evo is out and about I am usually putting it through its paces.



-Bink

 

There are two maintenance schedules for your car, regular and severe duty. Both schedules specify that plugs be changed every 60,000 miles.

 

I can confirm that. Almost every mile on my car is a track day mile. Copper plugs need more attention but you wouldn't catch me running DSM plugs in an EVO. Plug technology has come a long way since then. No reason to run a Seadoo plug in an EVO.

 

EvoVan is right. You don't get much metal degradation with iridium so the gap won't open up very much over time. Unless they're fouled with carbon or oil, you shouldn't have a problem with your plugs. Have you taken them out to look at them?

 

Mitsubishi specifies NGK ILFR7H. Gap should be 0.5-0.6mm. If the gap is not right, get another plug. Don't adjust the gap on iridium plugs.

 

Torque spec. is 18±4 ft-lb.