indexing sparkplugs [Merged 7-8] index plug plugs spark

[romeen]

I'm not sure if this would provide any benefit given the design/shape of our combustion chambers. Has anyone tried it? If so, what difference if any did you notice?

 

[Freerevving]

They actually use a dynometer a lot... And he drag races as well as circle track (nascar style, just not nascar)

He claims they were doing a test on just plugs... back to back, 2 or 3 runs a piece with small cool downs between... The same way everyone dyno-tunes to squeeze their last 5-10hp. He gets to dyno-tune more than anyone else I've talked with.

Flame quench is any surface that inhibits flame growth... is usually referred to anything close to the flame kernel:

A method was devised which uses ion probe detection of flames burning through a gap inside the combustion chamber to provide rapid and convenient measurement of two-surface flame-quench distances in an operating engine.^This method was used to establish that such quench distances range from about 0.01 cm to greater than 0.2 cm, depending in decreasing order on equivalence ratio, manifold pressure, wall temperature, spark timing, and fuel type.^A comparison between these experimental findings and the results from one- and two-surface measurements performed by others indicates that two surface quench values are 2.5 to 12 times greater than one-surface values

variables can increase the quench distance... basically what's in the center of the cylinder affects flame propogation

We're of different schools. I'd bet if you didn't know your iridiums had been swapped-out, you'd never realize they were.

Well, you're probably right... I originally said "it's hard to tell on the turbo 4g63"... the Denso iridiums have ran just as well, and the plugs were cleaner with no erosion in comparision... On the other hand I've seen definite improvements on 9A engines, PLs KR's, high compression engines, and Japanese and german alike.... these same engines improved with NGK coppers when compared to their (sometimes Bosch Super Tri-electrode) OE plugs.

And you are absolutely right about it being an obsessive "car guy" type behavior. To me it's one of those nice things like having bronze valve guides or polished aluminum parts. I'm just trying to clarify that Denso Iridium plugs or Bosch WR7DS are not going to make performance worse.

93 octane (we don't have 91 in Texas)

That's just cheating, then.

Haha L O L... I guess
actually 91 octane will work at 12:1 compression. 93 just gives you room to play
Honda builds cars that have 11:1 compression and the recommended fuel is 87 octane

 

[TunaTalon]

And you are absolutely right about it being an obsessive "car guy" type behavior.

Don’t discount the power of obsessive compulsive behavior. So it may lead to paying extra for plugs that may are not worth the difference to the average person, and to washing your hands after changing the plugs and before opening the beer. So what? People who aspire to be average don’t drive ten year old cars with double the original horsepower.

When striving to be the best in a competitive technology field I compulsively drove home the same old point to the design team. How can you be better if you aren’t different?
My Talon has Iridium plugs. I chose the Iridium plugs because of the first principles of a smaller center electrode being better releasing a spark under higher pressure. (Ok, ok, and to be different)

 

[Zex4g63]

I am involved with super stock engines, and having played with indexing more than I care to discuss I will tell you that it makes horsepower. It might only be three, four, or seven horsepower, but that is the difference between winning and losing. I will add that as long as the plug is aimed in the general direction of the intake valves it will work. You just don't want the ground strap blocking the intake charge.