Indexing Spark Plugs
 

Has anyone ever tried this? I know it doesn't make much of a difference on n/a motors, but what about on forced induction?

We have four-valve DOHC engines with the plug directly in the center of the chamber. What exactly would you index it to?

yeah, the V8 guys would point the gaps toward the intake valve. I guess you could point the gaps between the intake valves but I doubt it would not make a difference but it would not hurt either.

Intake valves.

i hear it's good for at least 10hp per plug. i'm gonna go spin mine

Tried doing this many times on a 275hp Honda B Series NA engine. Did not do shit except for take a few more minutes to install plugs.

Don't waste your time!

I would rather know my plugs are all torqued correctly then indexed right to get a .25 hp gain.

Try side-gapping the plugs...it works.

I have been doing this since the early 90's.

Tony

Read here:
http://performanceunlimited.com/docu...degapping.html

effort.

Then you should have plenty of before-and-after dyno charts to post, so we can see the effect of side-gapping upon performance.

I would need to see a few back-to-back dyno runs with at least a couple different sets of each plug configuration using brand-new plugs to be convinced. Power and AF's would begin to tell the story.

The indexing thing makes sense, but so do a lot of things that don't actually work better. If there was a computer modeling program that dealt with combustion chamber flow characteristics and flame-front vs. spark exposure and it was SCIENTIFICALLY proven to have your plug "FACE" the incoming fuel/air mixture then it might be worth the time.


I also have to wonder why you can't simply buy a pre-side-gapped plug. Makes you wonder if side-gapping produces a superior spark that Autolite or Denso would know abuot it? I ABSOLUTELY DO NOT BUY the size difference in the little cartoon flames in Chads link. That shit does not fly, but it was a great link so I know what we're talking about.

The same goes for indexing. If it produced even a .1% benefit in efficiency or power output, then it would be industry standard. Every car out there would come like that. Seriously, could you imagine what a car company would give to get .1% for free.

Just for shitz and grins, I'm gonna buy a new set of plugs next time I hit Autozone and do both of these techniques... I'll let y'all know.

A bit of sarcasm?

I threw the technique out there...do what you want with it.


Tony

Sarcasm? I don't think so. Seeing/Believing method for sure!

To bad we did not have a cartoon pic of that 1.8 oil/water cooler-heater, huh?;)



Note to self.....Sam understand cartoon pictures. :) Only.

I don't endorse this method of spark plug molestation in any way shape or form. Especially the weird cartoon spark it produces in your motor.

I merely posted a link i found via google, didnt' even look at the damn page actually.

Cartoon Powah Ftw

Well, you sort-of can. Here is a snipped from NGK's racing plug chart:

http://img34.picoodle.com/img/img34/...dm_4eaf468.gif


Pretty much any ground electrode configuration you can imagine, they've produced. Top-gap, side-gap, diagonal-gap, recessed electrode, even one style with no ground electrode at all (the spark simply jumps across the surface from center to outer.)

Source: http://www.ngk.com/charglossary.asp?...g+number+chart

Trouble is that all the research I can find pertains to two-valve American engines with asymmetrical chamber design and offset plugs. Said research generally indicates that gains of up to 1% are achievable with proper dyno testing to determine the optimum orientation, and that said orientation is different for different motors. This is probably a worthwhile expenditure for teams in NASCAR and other mega-budget series running pushrod engines, but I just can't see it paying dividends in an engine where the plug is in the center of a symmetrical combustion chamber.