When I changed the plugs on my Mitsubishi Lancer from NGK laser iridium to Denso iridium TT, I was surprised how smoothly the engine can run on low rpm now. Don't get my wrong, NGK are really good plugs. Later I have installed this kind of plugs on other cars and noticed the difference on all of them. Still after more than 50k miles my Lancer runs like a swiss watch! I assume it is the design that makes the difference. However Denso for me is the absolute winner in the match between spark plugs.
Использую у себя в машине, а также мои знакомые denso iridium TT! Отличные свечи! Запускал двигатель в -30 по Цельсию(без ночных прогревов). Привет из Сибири(Иркутск, Байкал)
You might want to check your starter amperage draw, I've done several VAG starters on the 1.8T for slow crank/high amp draw and they all started out sounding like yours a year to a few months before they started to draw so many amps the cars had problems starting reliably. Your spark plug experience mirrors my own with an older high compression Toyota. The IRTT idle smoother, start more easily, and feel more refined and precise than standard style Iridium plugs like the NGK IX's I had. Supposedly they'll also maintain that ideal performance much longer even under harsher conditions. They're a mass market version of the Denso Super Ignition Plug (SIP), if you want to dive into the R&D behind them there's a few papers and resources on them outlining some of the testing and development, a collaboration between Denso and Toyota starting in 2003. Basically the two fine points provide a more consistent and precise spark location and intensity with lower firing voltages.
Biggest difference in my setup is so far the denso tt are the only plug that I have yet to get spark blowout under low rpm high boost. I'm fully tuned and big turbo but with stock ignition coil and it's an issue with these cars as not enough coil energy for lower rpm higher boost situation. I've had some success with ngk v power gapped at .024 with the occasional blowout but they wear very fast and need to recap them every month. But so far with the denso tt gapped at .030 not one blowout. And seems to have a more complete burn like you mentioned. Only couple hundred miles but so far amazing.
Regapping plugs is a hassle. Used NGK Laser Platinums on a different engine, and was always an issue. Changed to TTs and no issues. Didnt have the Lasers on the 1.8T long enough to see if it had the same issue.
This may be an unfair test because the NGKs have been on the car for a couple of months whereas the Denso have been on for a week. If my opinion changes on the plugs, I'll do an update video and leave a comment here. (Subscribe for any update)
