Hi,
I kind of inadvertently mentioned indexing spark plugs in the Performance thread about drop-ins vs. C.A.I. kits, and was asked to start a new thread.
As I am pressed for time at the moment, please refer to that thread for additional info/results.
Basically, indexing refers to pointing the electrode of the plug towards EITHER of the valves instead of pointing it into a "dead area" of the combustion chamber. If that is done (pointing it away from the valves, which you don't want to do), the theory is the flame front started by the spark is partially shielded by the electrode and decreases combustion efficiency inside the chamber.
As the plug threads are all different, I buy 20 plugs. I don't use washers, but you can if you like. Mark the plug socket with a felt pen to show where the electrode is pointing and install the plug so it is pointing at either valve. If the one you just installed (for example) doesn't point in the right direction, try another one. (Make sure they are the correct tightness).
Here is a good shot of the Viper's combustion chamber. Go to:
http://www.performancecylinderheads.com/Viperpage.htm
**My apologies to those in the cylinder head business, I am using this site ONLY because it has an excellent photo of what I am trying to explain.**
It was good for a free 9+ h.p. gain (used plugs even!) on my SRT-10. Better than what was gained with the drop-in.
I would guess maybe more h.p. with brand new plugs.
Gotta Run
Ronnie
I kind of inadvertently mentioned indexing spark plugs in the Performance thread about drop-ins vs. C.A.I. kits, and was asked to start a new thread.
As I am pressed for time at the moment, please refer to that thread for additional info/results.
Basically, indexing refers to pointing the electrode of the plug towards EITHER of the valves instead of pointing it into a "dead area" of the combustion chamber. If that is done (pointing it away from the valves, which you don't want to do), the theory is the flame front started by the spark is partially shielded by the electrode and decreases combustion efficiency inside the chamber.
As the plug threads are all different, I buy 20 plugs. I don't use washers, but you can if you like. Mark the plug socket with a felt pen to show where the electrode is pointing and install the plug so it is pointing at either valve. If the one you just installed (for example) doesn't point in the right direction, try another one. (Make sure they are the correct tightness).
Here is a good shot of the Viper's combustion chamber. Go to:
http://www.performancecylinderheads.com/Viperpage.htm
**My apologies to those in the cylinder head business, I am using this site ONLY because it has an excellent photo of what I am trying to explain.**
It was good for a free 9+ h.p. gain (used plugs even!) on my SRT-10. Better than what was gained with the drop-in.
I would guess maybe more h.p. with brand new plugs.
Gotta Run
Ronnie
