Notices
General Miata Chat A place to talk about anything Miata

Indexing Spark Plugs

Thread Tools
 
Search this Thread
 
Old Jun 22, 2008 | 06:29 PM
  #1  
kenzo42's Avatar
Thread Starter
Elite Member
iTrader: (6)
 
Joined: Sep 2007
Posts: 2,017
Total Cats: 13
From: CA
Default 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?
Old Jun 22, 2008 | 07:02 PM
  #2  
Joe Perez's Avatar
Boost Pope
iTrader: (8)
 
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Default

We have four-valve DOHC engines with the plug directly in the center of the chamber. What exactly would you index it to?
Old Jun 22, 2008 | 07:12 PM
  #3  
Stealth97's Avatar
Elite Member
iTrader: (5)
 
Joined: Oct 2007
Posts: 2,156
Total Cats: 67
From: Canton, Ga
Default

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.
Old Jun 22, 2008 | 08:33 PM
  #4  
kenzo42's Avatar
Thread Starter
Elite Member
iTrader: (6)
 
Joined: Sep 2007
Posts: 2,017
Total Cats: 13
From: CA
Default

Intake valves.
Old Jun 22, 2008 | 08:37 PM
  #5  
paul's Avatar
Elite Member
iTrader: (21)
 
Joined: Jun 2006
Posts: 2,957
Total Cats: 2
From: Point Pleasant, NJ
Default

i hear it's good for at least 10hp per plug. i'm gonna go spin mine
Old Jun 22, 2008 | 09:18 PM
  #6  
M-Tuned's Avatar
Guest
iTrader: (6)
 
Joined: Sep 2007
Posts: 1,085
Total Cats: 1
From: Vaughan, On, Canada
Default

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

Don't waste your time!
Old Jun 22, 2008 | 09:22 PM
  #7  
cjernigan's Avatar
Elite Member
iTrader: (13)
 
Joined: Oct 2006
Posts: 8,091
Total Cats: 7
From: Atlanta, GA
Default

I would rather know my plugs are all torqued correctly then indexed right to get a .25 hp gain.
Old Jun 22, 2008 | 09:27 PM
  #8  
mrtonyg's Avatar
Junior Member
iTrader: (1)
 
Joined: Mar 2007
Posts: 483
Total Cats: -2
From: South Florida
Default

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

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

Tony
Old Jun 22, 2008 | 09:54 PM
  #9  
cjernigan's Avatar
Elite Member
iTrader: (13)
 
Joined: Oct 2006
Posts: 8,091
Total Cats: 7
From: Atlanta, GA
Default

Read here:
http://performanceunlimited.com/docu...degapping.html
Old Jun 22, 2008 | 10:00 PM
  #10  
Braineack's Avatar
Boost Czar
iTrader: (62)
 
Joined: May 2005
Posts: 80,552
Total Cats: 4,368
From: Chantilly, VA
Default

effort.
Old Jun 22, 2008 | 10:27 PM
  #11  
Joe Perez's Avatar
Boost Pope
iTrader: (8)
 
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Default

Originally Posted by mrtonyg
Try side-gapping the plugs...it works.

I have been doing this since the early 90's.
Then you should have plenty of before-and-after dyno charts to post, so we can see the effect of side-gapping upon performance.
Old Jun 22, 2008 | 11:34 PM
  #12  
samnavy's Avatar
Elite Member
iTrader: (7)
 
Joined: Apr 2006
Posts: 6,463
Total Cats: 327
From: VaBch, VA
Default

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 **** 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.
Old Jun 23, 2008 | 12:04 AM
  #13  
mrtonyg's Avatar
Junior Member
iTrader: (1)
 
Joined: Mar 2007
Posts: 483
Total Cats: -2
From: South Florida
Default

Originally Posted by Joe Perez
Then you should have plenty of before-and-after dyno charts to post, so we can see the effect of side-gapping upon performance.
A bit of sarcasm?

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


Tony
Old Jun 23, 2008 | 12:10 AM
  #14  
Dark Wanderer's Avatar
Junior Member
iTrader: (2)
 
Joined: Dec 2007
Posts: 403
Total Cats: -1
From: Québec, Canada
Default

Originally Posted by mrtonyg
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!
Old Jun 23, 2008 | 12:21 AM
  #15  
IcantDo55's Avatar
Elite Member
iTrader: (11)
 
Joined: Apr 2007
Posts: 2,010
Total Cats: 52
From: VA Beach
Default

Originally Posted by samnavy
I ABSOLUTELY DO NOT BUY the size difference in the little cartoon flames in Chads link. That **** does not fly, but it was a great link so I know what we're talking about.
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.
Old Jun 23, 2008 | 12:43 AM
  #16  
cjernigan's Avatar
Elite Member
iTrader: (13)
 
Joined: Oct 2006
Posts: 8,091
Total Cats: 7
From: Atlanta, GA
Default

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.
Old Jun 23, 2008 | 12:53 AM
  #17  
IcantDo55's Avatar
Elite Member
iTrader: (11)
 
Joined: Apr 2007
Posts: 2,010
Total Cats: 52
From: VA Beach
Default

Cartoon Powah Ftw
Old Jun 23, 2008 | 10:58 AM
  #18  
Joe Perez's Avatar
Boost Pope
iTrader: (8)
 
Joined: Sep 2005
Posts: 34,402
Total Cats: 7,523
From: Chicago. (The less-murder part.)
Default

Originally Posted by samnavy
I also have to wonder why you can't simply buy a pre-side-gapped plug.
Well, you sort-of can. Here is a snipped from NGK's racing plug chart:




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.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Zaphod
MEGAsquirt
47
Oct 26, 2018 11:00 PM
StratoBlue1109
Miata parts for sale/trade
21
Sep 30, 2018 01:09 PM
nick470
MEGAsquirt
7
Jun 16, 2017 01:53 PM
The Gleas
MEGAsquirt
3
Oct 1, 2015 09:30 AM
FrankB
Miata parts for sale/trade
6
Sep 30, 2015 11:48 AM




All times are GMT -4. The time now is 01:22 PM.