Originally Posted by No Warning Shot
With a dual plug ignition system, how much more would different plugs really help?
Depends, but they can actually hurt if you don't know what's going on in your engine... You are correct about the dual plug system, it was designed to completely burn all vapors to limit exhaust emissions and meet CARB/EPA standards. That's the only reason... The down side to this design is that the ECU is programmed to tell the coil pack to fire #1 & #2 a millisecond apart for a complete burn depending on the signals from the 02 sensors, instead of a simultaneous firing. This helps maintain the "perfect" 14.7:1 +/- AFR for the CARB/EPA standards, not maximum HP...
What fascinates me about all this hyperbole about performance is that nobody has yet to discuss specific modifications to the engine management system / fuel management system to achieve and maintain the optimum AFR to develop maximum HP from the OEM set-up... That can range from 11:1 to 12.5:1 for forced induction +/- depending on the engine, and 12.5:1 to 13.5:1 for naturally aspirated engines +/-. The OEM system will always attempt to maintain 14.7:1 even with "off the shelf" ECU re-tune programs...
Whatever you do with your spark plugs, do not install hotter plugs in the OEM "stock" engine, because you don't need it, and it will send your cylinder temps thru the roof "so to speak"...
What you need is to adjust the AFR to the optimum level for your modifications and prevent the programming in the Bosch ME 2.8 / 2.8.1 ECU/PCM/FMU from readjusting it...