Indexing Spark Plugs
06-22-2008, 11:34 PM
#12
I would need to see a few back-to-back dyno runs with at least a couple different sets of each plug configuration using brand-new plugs to be convinced. Power and AF's would begin to tell the story.
The indexing thing makes sense, but so do a lot of things that don't actually work better. If there was a computer modeling program that dealt with combustion chamber flow characteristics and flame-front vs. spark exposure and it was SCIENTIFICALLY proven to have your plug "FACE" the incoming fuel/air mixture then it might be worth the time.
I also have to wonder why you can't simply buy a pre-side-gapped plug. Makes you wonder if side-gapping produces a superior spark that Autolite or Denso would know abuot it? I ABSOLUTELY DO NOT BUY the size difference in the little cartoon flames in Chads link. That **** does not fly, but it was a great link so I know what we're talking about.
The same goes for indexing. If it produced even a .1% benefit in efficiency or power output, then it would be industry standard. Every car out there would come like that. Seriously, could you imagine what a car company would give to get .1% for free.
Just for shitz and grins, I'm gonna buy a new set of plugs next time I hit Autozone and do both of these techniques... I'll let y'all know.
The indexing thing makes sense, but so do a lot of things that don't actually work better. If there was a computer modeling program that dealt with combustion chamber flow characteristics and flame-front vs. spark exposure and it was SCIENTIFICALLY proven to have your plug "FACE" the incoming fuel/air mixture then it might be worth the time.
I also have to wonder why you can't simply buy a pre-side-gapped plug. Makes you wonder if side-gapping produces a superior spark that Autolite or Denso would know abuot it? I ABSOLUTELY DO NOT BUY the size difference in the little cartoon flames in Chads link. That **** does not fly, but it was a great link so I know what we're talking about.
The same goes for indexing. If it produced even a .1% benefit in efficiency or power output, then it would be industry standard. Every car out there would come like that. Seriously, could you imagine what a car company would give to get .1% for free.
Just for shitz and grins, I'm gonna buy a new set of plugs next time I hit Autozone and do both of these techniques... I'll let y'all know.
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06-23-2008, 10:58 AM
#18
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Well, you sort-of can. Here is a snipped from NGK's racing plug chart:
Pretty much any ground electrode configuration you can imagine, they've produced. Top-gap, side-gap, diagonal-gap, recessed electrode, even one style with no ground electrode at all (the spark simply jumps across the surface from center to outer.)
Source: http://www.ngk.com/charglossary.asp?...g+number+chart
Trouble is that all the research I can find pertains to two-valve American engines with asymmetrical chamber design and offset plugs. Said research generally indicates that gains of up to 1% are achievable with proper dyno testing to determine the optimum orientation, and that said orientation is different for different motors. This is probably a worthwhile expenditure for teams in NASCAR and other mega-budget series running pushrod engines, but I just can't see it paying dividends in an engine where the plug is in the center of a symmetrical combustion chamber.
Pretty much any ground electrode configuration you can imagine, they've produced. Top-gap, side-gap, diagonal-gap, recessed electrode, even one style with no ground electrode at all (the spark simply jumps across the surface from center to outer.)
Source: http://www.ngk.com/charglossary.asp?...g+number+chart
Trouble is that all the research I can find pertains to two-valve American engines with asymmetrical chamber design and offset plugs. Said research generally indicates that gains of up to 1% are achievable with proper dyno testing to determine the optimum orientation, and that said orientation is different for different motors. This is probably a worthwhile expenditure for teams in NASCAR and other mega-budget series running pushrod engines, but I just can't see it paying dividends in an engine where the plug is in the center of a symmetrical combustion chamber.
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