Hey guys what plug range do you reccommend for high boost (35-40psi) using 50/50 water meth. Should I use a 7 or 8 plug?

 

I would just use a 7. The cooling effect of the w/m should be enough. If you are breaking up go with a 8. Luckily they are only like 2 bucks a piece.

 

As cold as possible until daily driving is effected. Been using BR9ES often for couple years. The bad: at low loads where cyl psi/temp can't keep C off, colder plugs will load up and cause a miss. The good: you drastically reduce the chance of CHT induced preignition (compared to NGK 7/8 and >). The BR8ES won't load up though.

 

Wow 9s! My car would not let me run the 8s without breaking up . So the purpose is the of a colder plug is to help prevent preignition? What do you think of the iridiums with meth. I though I read some one say to stear clear but I don't remember why? Or if it was just hear/say... I would like to try the iridiums but am paranoid about it now.

 

My car is not liking the 8s as well. Might have to consider some COP ignition

 

I run the 7 although am considering going iridium lately. My spoolin up cop cleared up all of my miss firing.

 

Just pull one of your plugs and read the color on it to see if it is white and chalky, normal brownish, or blacked. Usually stock heat range plugs are used in combination with W/M due to the knock suppression and intake air charge cooling the injection brings to the motor.