Car: 57 plate CTR GT
Join Date: 28th January 2017
Thanked 7 Times in 7 Posts
Me personally i've never needed a reason to go to a colder plug on an N/A engine, I've had to do it on my boosted cars but that's cos the boost was raised along with other mods to support a +50% power increase, unless you have a high comp engine kicking out a load of power then the standard plug will probably be fine.
NGK state that a general "rule of thumb" is 1 grade colder for a 75-100bhp increase...i dare say there will be some exceptions to that, but it gives you an rough idea of when you should be looking at plug temp range.
Last edited by weegaz22; 5th March 2017 at 11:30.