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  #16  
Old 01-17-2009, 07:24 PM
Deviant Deviant is offline
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I wonder if the MINI would benefit more from indexing towards one of the intake ports, towards the area between the intake ports, or, since it's using forced induction, you'd actually want to try and index away from the intake side altogether.
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  #17  
Old 01-17-2009, 08:56 PM
Nitrominis Nitrominis is offline
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Here are few sites to read about indexing. This has been a proven technique for years!

Posted by NGK
Spark Plug Installation Instructions

http://www.ngksparkplugs.com/techinf...stallation.asp


Indexing Spark Plugs:

http://www.advanceautoparts.com/engl...20001001sp.asp

very interesting test:

http://dodgeram.org/tech/gas/spark_p...0_indexing.htm

Extremely good readin!

http://www.nhra.com/dragster/1999/is...echnology.html


There are many other sites like these.

Last edited by Nitrominis; 01-17-2009 at 09:20 PM.. Reason: added: http://www.nhra.com/dragster/1999/issue25/racing_technology.html
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  #18  
Old 01-18-2009, 03:38 AM
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Isn't this less of an issue on a "multi-pronged" plug like the NGK BKR 7? I thought this was something that applied more to old-school plugs with a single "overhead" electrode. Can the the BKR 7s even be gapped?
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  #19  
Old 01-18-2009, 03:53 PM
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I don't like the multiproned plugs for that very reason. Really the gap is pretty important IMO and really no matter how many electrodes you have you only get one spark going to one electrode. Multiple electrodes make for a more efficient plug if you follow the 100K mile service interval some of them recommend. You can't really index a multi electrode plug, you can't really gap it, you can't really optimize them for performance.
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  #20  
Old 01-18-2009, 06:44 PM
Nitrominis Nitrominis is offline
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Quote:
Originally Posted by xalfa View Post
Isn't this less of an issue on a "multi-pronged" plug like the NGK BKR 7? I thought this was something that applied more to old-school plugs with a single "overhead" electrode. Can the the BKR 7s even be gapped?


"old school"

I get reminded of this often with stuff I do. But 2 + 2 still equals 4 and the laws of physics still apply.

You are correct in saying the multiple-pronged plug is not a choice for indexing. I believe the manufactures goal was high millage not high performance in the design.

You might read a couple of the informational sites I posted. Indexing is a Pandora's box of other things that should be followed with regards to the ignition to take full advantage. If you take it that far? You should look to see what it takes to actually find a correct plug, heat range and gap for optimum performance?
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  #21  
Old 01-23-2009, 02:52 AM
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This is something I would do but just becasue its free not for any real power. My opinion is its something thats still around form the hemi days when heads didnt flow as well as they do now, to me a 4 valve head wont benefit as much as a 2 v head.

Also if your running any of those multi ground strap plugs this is more or less pointless

just my .02
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  #22  
Old 01-23-2009, 04:47 AM
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It's free but if indexing them a certain direction makes more power wouldn't indexing them in the wrong direction cause a loss in power? If you look at it that way the cost of the indexing washers could be going towards reducing power. I'm not saying don't do it, but if you do it, do it right with your car on a dyno, don't just assume what works on one vehicle works on another.
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  #23  
Old 01-25-2009, 01:20 AM
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My plugs have four prongs. Chances are they are already indexed!
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  #24  
Old 01-25-2009, 02:02 AM
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Quote:
Originally Posted by Second to none View Post
My plugs have four prongs. Chances are they are already indexed!
Unless the spark jumps to a prong that is at 90 degrees to an intake valve or towards the exhaust valves. Then it is not.
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  #25  
Old 01-25-2009, 03:08 AM
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So current info from leading plug manufactures does not help to explain a old/current practice.

Another excellent source would be to contact a performance shop that has an in house DYNO and perhaps they can give some useful information and perhaps some Dyno pulls on engine run with indexed plugs.





Thought of the day:

Electricity will find the direction of least resistance.
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  #26  
Old 01-25-2009, 04:38 AM
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When plugs threaded into the side of the combustion chamber (most older engines), or in L or Flat head engines You didn't have the plug in the center of the cylinderhead and the flame front would originate on once side of the piston and advance across the piston face, in these cases indexing the spark plugs could have a more dramatic effect as the electrode itself could impede this flame front some. With hemispherical combustion chambers the spark is centered so combustion is overall more efficient and the electrode doesn't impede the flame front in the same way.
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  #27  
Old 01-30-2009, 06:26 AM
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I'll be taking some pictures tomorrow of a stock head and its combustion chambers. I'll post them up, as I don't recall the exact shape of the combustion chamber but for some reason don't believe it to be hemispherical I could be wrong and will know for sure in 11 hours.
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  #28  
Old 01-30-2009, 06:45 PM
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Def not hemispherical its a pent-roof design most of the combustion chamber is inside the block (thanks Chris for that tip). Forgot my cable so pics up tonight.
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  #29  
Old 01-30-2009, 06:58 PM
Nitrominis Nitrominis is offline
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From this picture it is easier to see how indexing would benefit?

Click the image to open in full size.
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  #30  
Old 01-30-2009, 07:02 PM
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lol al lot cleaner than the one I have.
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