NA spark plug questions

[akhilleus]

Ok so i am currently using the platinum NGK extended reach...however they are one step colder than normal@6.. This was just an experiment since custommsp had them lying around, and i needed new plugs. Now i am going to buy the NGK Vpower extended reach since i know that NA's need a hotter plug, but i was wondering how many steps hotter they go. I can go back to 5...but is there anything lower/hotter than that. ANd what is the extended reach part #...its prefix is BZ right?

 

[p5sundevil]

here are their Vpower racing plugs...
http://www.ngksparkplugs.com/products/racing/vpowerracing.asp?nav=16200&country=US

basic description of their "racing" plugs...
http://www.ngksparkplugs.com/products/racing/racing.asp?nav=16100&country=US

their tech info section is impressive also to learn how plugs work, heat ranges and how engine applications affect said properties.

part numbers for alot of spark plugs
http://ngkaz.home.att.net/wsb/html/view.cgi-home.html-.html

 

[akhilleus]

Great site!! So maybe i should stick with these plugs...it does say that camshaft change, ie increased compression warrants colder plugs....but i dont know if i have made enough of an impact to have that matter. Any suggestions?

 

[Ghost Buster]

from what I've seen the type of plug is not as important as the condition of the plug and there is more power to be had by indexing the plugs than by using some fancy tip. Especially on NA.

 

[akhilleus]

Indexing? u mean heat range? Plug quality has always been good in my car...no unburnt or lean mixtures yet.

 

[Ghost Buster]

indexing is rotating of the plug inside the head to verify that the electrode isn't deflecting the A/F mixture as it enters the combustion chamber. With the electrode exposed to that incoming charge it doesn't ricochet around the chamber...it just falls directly onto the spark.

This has been a big nascar trick for many years.

 

[akhilleus]

How would one index the plug? I could understand that considering the electrode design it could split or interefere with a charge. Would u just rotate it so that the electrode arm is opposite the IM or charge direction.

 

[Ghost Buster]

our heads make it a little trickier but basically you would take your SP socket and an extension and insert the plug into the socket. Note on the extension with a sharpie where the open electrode face is. Now slowly tighten the plug back inside the head and note on the valve cover opening where the dot on the extension is....basically you'll have like a pac-man head. I just measured the angle of the two dots and used a pre-sized washer to snug the plug up until the dots lined up.

I got the pre-measured washers from Jacobs Electronics. The kit of like 30 washers was $10+ shipping but each baggy was pre-marked with how many degress it would "index" the plug in the head.

I did this on my mustang and picked up 4whp just by indexing.

 

[akhilleus]

Crap, nice #'s! I figured i could mark the ratchet/extension ...but what about when u torque it down...? I guess the washers adjust for that. But one could offset the electrode area enough to make sure it lined up with the torque wrench. I am going to try that...thanks man!!

 

[Ghost Buster]

no prob Bob. Just make sure only 1 washer per plug.....actually I have my extra washer set right here. Just pm with what numbers you need and I'll mail em to you.

 

[akhilleus]

thanks ...i will definately be in touch.

 

[Installshield 2]

Yeah Aky, the you shouldn't need to mess with heat ranges too much at this stage...and FI and NA engines tend to prefer colder plugs once big compression or boost come into play, and it is mostly due to a higher need for detonation prevention...

Let us know how it goes with the indexing...I haven't tried it on this engine, but probably couldn't hurt...

 

[Gen1GT]

I'd use the colder plug too. If you're like me, and run the engine to redline all the time, you'll burn off any carbon deposits even with a colder plug.

Indexing is useless on our car. It's a trick for old V8s, with horrible combustion chambers and 2 valves per cyl. If you recess the plug anymore in the head, you won't get a good even burn, because flame front starts too far up and in.

Look at the pic of the BP combustion chamber. The FS isn't a whole lot different. There'd be no advantage to indexing a plug, it would probably hurt it. Our combustion chambers are so well designed to start with. My factory setting for initial ignition timing is a scant 10 degrees. That tells you how efficient the chamber is. V8s run 20 degrees or more. Japanese engineers are very good at what they do......

 

[akhilleus]

But the electrode arm could still interefere with the charge. I am going to try it...anyways

 

[shinzen]

Also, with the extended reach plugs, you wont be recessing the plug further than the stock ones are fromt the factory- you have quite a bit of play there. I have been meaning to try this myself, lemme know if you notice a difference.

 

[Ghost Buster]

you'd be best off to run a dyno pull. index them and run another series.

Like I mentioned earlier I gained 4whp on my 'stang and it was an average. We made sure to make 3 pulls before and 3 after for consistency.

 

[akhilleus]

Yeah i was thinking i would do it while getting dyno runs done. Let me make sure about something though...am i only rotating the plugs to the desired location..ie electrode arm opposite from intake valves...or am i actually recessing the plugs as well...if so explain this..

 

[Ghost Buster]

the washer adds a SLIGHT decrease in the amount of plug that is in the combustion chamber. If you use an extended reach plug this should more than negate the difference.

You're correct, you are only making sure that when you tighten the plug down that the electrode is facing the incoming charge.

Gen1Gt, despite improvements in head design simple physics still apply. It's ALWAYS better to dump the fuel and air directly on the spark as opposed to letting it be deflected by the electrode.

 

[akhilleus]

why would u want to recess the plug...what advantage would this have.... is it to offset the improved charge ignition ability

 

[Installshield 2]

I am not sure what you mean by dumping the fuel on the spark rather than deflecting it...I understand indexing, and I have seen it done on even tuned Honda engines and yeild 2whp...But the advantage has nothing to do with dumping the fuel on the electrode, it just provides better area for the aerosol'd gasoline and air to mix...making an even, more powerful expansion...on "some" engines, it doesn't work for all of them, it simply allows for more even and better swirling affects, which provideds better fuel/air mixing...

It is not good to have injectors aiming directly on an electrode though...You do not want wet spark plugs by any means...If they are saturated with puddled fuel, they give goofball sparks that make goofy expansions, and can even send the plugs packing (Even worse, they can get hot enough for them too loose a chunk...yeilding a floating chunk of porcelain (sp?) or metal...and scattering your entire mill)...This was a somewhat common problem with KL V6 owners using phenolic spacers and longer plugs...There fuel rail was mounted on the intake manifold, and when the spacers were installed, it changed the angel and position of the injectors...ended up that if longer reach plugs were being used, the injectors were spraying directly onto the plugs (or bouncing fuel off a cylinder wall onto the plugs)...Am I misunderstanding what you mean about "dumping air and fuel on the spark"?...and the spark plug is not igniting when the air and fuel is just entering...