Originally Posted By: Vikas
Call me stupid but I am not going to trust few Hyundai knuckleheads on a forum over the factory documentation.
Reading that topic immediately tells me that neither of the guys writing there has seen his 30th birthday yet aka it is all baloney. The days when spark plug gap made a difference in the running of a engine went away with high voltage electronic ignition.
If you think you can take .40 plug from the factory and gap it to .30 to get more power from the engine, who am I to stop you?
Just shrinking the gap will, if anything, hurt power. A larger gap is better. But on a turbo engine when you start turning up the boost, you'll hit a point where you either need to gap the plugs smaller or upgrade the ignition system. If you do neither, you'll start to get spark blowout and misfires at high rpm under heavy throttle.