They're almost the same plug - according to NGK's spark plug guide the S has a standard 2.5mm electrode and the A is a 'special design' - no more info given than that!
Read more: http://wiki.answers.com/Q/Difference...#ixzz21BC7PPr4
Anyone have any more info. This is the plug I bought today. Should I get the dr8EA or stick with the dr8ES?
A very very wise man once said “it’s more fun to ride a slow bike fast, than a fast bike slow”.
"Now then get your weapons... and go out to the open country to hunt some wild game for me"
“I've noticed that everyone who is for abortion has already been born.”
Good mystery you have here
Ngk cross ref from regular to iridium plugs shows something is afoot
DR8EA = DR8EIX
DR8ES = DR9EIX
DR8ES-L = DR8EIX
I've seen bits about special design meaning "The electrode has a small split on the end of it to help produce a better spark".
But someone else said special design meant " If you look closely at porcelain part below the firing tip and will see how far sunken it is below the thread part".