Postby CD4Accord » January 26th, 2011, 9:25 pm
Oh crap man, i posted one big long scientific reply and it looks like it never went thru..
Lemme try again conscise version..
To racers: firstly, dynoing with used plugs vs new plugs is unfair as has been mentioned.
Secondly, 3hp on a dyno is almost nothing.. That is well within the margin of error for such things..
Concerning the use of silver as a spark plug tip material, while I agree that it is the best conductor out there, I also will say it has well known problems.. Firstly, it tends to oxidise and lose its finish (possible early fouling), therefore the heat and exposure within a combustion chamber wouldnt do any favours as compared to more chemically stable metals such as Platinum (PT) or Iridium (Ir)
Concerning the conductivity, I will agree that it will have the least resistance of all the metals mentioned, but this is not necessarily a benefit as resistance was never a problem on ignition systems..
This leads me to a comparison of density and therefore strength..
Silver, around 10.5 g per cm3
Copper about 8.5
Iridium ~ 22.5
Platinum 21.5
The advantage of increased density is increased hardness, which is the very reason that Ir and Pt plugs can have such small diameter tips and copper, nickel AND SILVER cannot..
So, while silver has less resistance, the use of a much larger (than IR or PT) spark tip will actually lead to a decreased concentration of spark, negating any possible advantages of less resistance in the first place.. As i mentioned before, resistance isnt a problem in such a high voltage system..
Finally, if silver was such a good idea, why dont NGK,Denso,Bosch,Champion etc, the biggest spark plug companies in the world bother to use it? By extension, why does NO OEM car come with silver plugs? Obviously they have done their R+D and know whats best and what isnt
So, in closing, to the OP, if you want to save some money, buy NGK G-Power, if you want to spend, buy the Iridium IX or Laser Platinium.. Im sure its less than the nology and is PROVEN quality and life...
In the end its your call...