Because of the spark plug change for the 3.5's it is only possible to get 1 step colder NGK copper plugs. This hasn't changed.

NGK now recommends their new Iridiuim IX plugs for nitrous applications and a number of Z guys have been using them successfully. They have finally started making one 2 steps colder which has just become available.

Part # is 2309 for the LFR7AIX-11. I had to call the head office and get them to pressure a dealer to order before I could get any action but I should have them next week. I am going to my next race on Oct 10 and will try them out and report back.

 

Awesome, I'd love to hear how it goes.

 

Update on the plugs.

Installed them last week and went to the track yesterday. Ran N/A all day and ended in 4th position but blew it myself wasn't the car.

Remember these plugs are 2 steps colder and I am running N/A.

I ran my quickest N/A time 13.531 and my first sub 2.0 60' which was a 1.98 so they definately work. Next weekend I may try it with the spray and see how it goes as well as a couple of other small changes. Also yesterday I didn't bother to put on my lighter rear tires and ran with the stock muffler.

 

great info jime, i will loook into those