Sparkplug Indexing...

Teams have been doing this in Top Fuel and many other motorsports for years, with dyno proven results...

It's basically using very thin washers to ensure that the plug strap faces away from the center of the combustion chamber. The best position is with the plugs firing center (directly opposite the strap), to be facing about 10-15 degrees towards the exhaust valve.

This apparently directs the flamefront through the chamber better, and prevents "awkward" ignition from a strap accidentally facing directly center (which happens often).

Increases idle smoothness, and low end HP, nothing much at top end i think...

Anyone done this before? Results?

The kits are about $10, can't hurt.?.?

TeK9iNe wrote:

Teams have been doing this in Top Fuel and many other motorsports for years, with dyno proven results...

It's basically using very thin washers to ensure that the plug strap faces away from the center of the combustion chamber. The best position is with the plugs firing center (directly opposite the strap), to be facing about 10-15 degrees towards the exhaust valve.

This apparently directs the flamefront through the chamber better, and prevents "awkward" ignition from a strap accidentally facing directly center (which happens often).

Increases idle smoothness, and low end HP, nothing much at top end i think...

Anyone done this before? Results?

The kits are about $10, can't hurt.?.?

I have not seen dyno tests on this done for a stock engine, but I will stick my nuts on the chopping block and predict that the difference is negligible (less than a couple of percent difference at most which is within measurement error range).

If you stand in a garage full of vaporized gasoline fumes and light up a cigarette, I do not believe the reaction that follows will change regardless of which way you are facing when you strike the match.

I could be wrong, but I would like to see some proof that indexing the electrode could have any measurable effect on a stock engine.

The reason I am skeptical is that seems to be similar to another scam going on about the new super duper spark plugs that "store" massive amounts of energy and then explode a huge spark. They published dyno tests and the difference was like .01%, which is less than the margin of error.

If there is free power to be had, I'd like to know but I am skeptical.

TeK9iNe wrote:

This apparently directs the flamefront through the chamber better, and prevents "awkward" ignition

that's the part I don't get. The chamber is full of compressed (highly explosive) fuel and you are lighting it at the "edge" not the center. I don't really understand how having the electrode at various positions makes any difference since the flame front still has to proceed outward and across the combustion chamber from what is essentially a point source on the edge. I'll defer to experts, but I don't see it.

You hear quite a bit about this from racers. I do believe it will make a difference if you are splitting .01 second intervals, I however do not believe it will make a difference on a street bike.

The reference I just looked at claims the gains are going to be seen in super high compression engines where the compressed volume is low and I suppose the flame front gets "crowded"(?)

I might believe on a 6000 HP drag engine some wierd things go on and benefit from such tweaking, I have trouble believing it could be seen on a stock engine. If it was true you could get a power gain from indexing, bike makers would be doing it for sure since it basically costs nothing to do.

I'm with Otakar.
If u can feel a dif on a stock motor , u need a better ignition system.
Poor ignition was common in tne old bikes. easy to upgrade now.

ive seen it done on plenty of v8s but never on a bike,keep us posted i say.

I saw some info on powerblock today on it. They had some fancy videos of the difference it makes in Big engines...
As far as for small engines, they would have to be heavily modified (lots of idle lope), and even then it really only assists at low idle.

Really, you could do this for free if you wanted.

:laugh: whatever! Something else to try...

Cheers.

On flat head engines we done it to keep the valves from smacking the gap closed. I can see it making a difference in other chamber styles with high cylinder pressures. Kind of like trying to strike your bic in high wind, cover it with your hand then it will light, point the gap at the right spot and it may be less prone to actually blowing out the flame front or at least make it somewhat more predictable.
Just a thought

I know I heard something about this from a NGK speech I went to. I can't remember for sure the car but I think it was a honda insight. Anyway you had to get special sparkplugs that were indexed to the head. They had them specified as A,B,and C. They basically made everything the same as any other engine but at the end of it all they figure out where the threads end and which plug it needs for it to be indexed properly.

i saw the same show lol i was thinking about it as well kinda makes sence to me although the only thing i think you make get out of it is better fuel econamy from a better burn