need to change my Spark plugs

[dizhungryguy]

I havent change my spark plugs ever since i purchased my evo its been almost two years and time to replace it. Before i posted this topic i did my search but still confused??. Now what will be a best spark plugs for my evo? ngk? denso? iriduim(sp)?. 1 step colder? two step colder? just go for oem ones?

by the way i dunno if it matters here's my engine set up

20g turbo
gsc s1 cams
ported manifold
tbe exhaust

Thanks in Advance guys

[earlyapex aka jack ass]

Stock should be fine for price/performance ratio.

[bricel24]

plugs for the 9 are different from the 8 right?

[earlyapex aka jack ass]

plugs for the 9 are different from the 8 right?


yup.

[dizhungryguy]

how bout 1 step colder?

[dizhungryguy]

anyone running this one

NGK EVO 9 Iridium Spark Plugs R7437-8 (1 Step Colder)

[trinydex]

going hotter (wider gap) is better as long as you have the energy to maintain spark. going colder (smaller gap) is ok if you're blowing out spark but it is suggestive of overall ignition strength shortcomings.

[ST]

anyone running this one

NGK EVO 9 Iridium Spark Plugs R7437-8 (1 Step Colder)


i ran the denso -1 plugs on my 9...worked great.

[bluevoiix]

i thought hotter and colder depended on the porcelin not the gap.. and i dont believe you should gap iridiums.
Check it out: http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml

[HassounEVO]

i thought hotter and colder depended on the porcelin not the gap.. and i dont believe you should gap iridiums.
Check it out: http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml

Exactly. Hotter and colder is determined by how high or low the porcelin insulator sits around the center electrode. Spark plug gap is the distance between the center electrode and the ground electrode (prong). I run NGK BPR8ES which are 1 step colder than stock, but that's because I run 27 PSI on 100 octane all the time... They're cheap copper plugs $2 each. Copper provides great spark, but doesn't last for shit. You have to change them A LOT more often (I change mine every 3k oil change) than Iridium/platinum....Â*

[trinydex]

i thought hotter and colder depended on the porcelin not the gap.. and i dont believe you should gap iridiums.
Check it out: http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml
it does but it also has to do with how you gap the plugs. each series of plug also has specs for where you're supposed to gap them.

[tam@xperformance]

Dave @ Rebello Racing put these pretty funky-looking plugs into my Spec Miata engine. He claims they make more power (and he's got an engine dyno rig so he's probably tested that). No real way to gap them though.

http://vitalmotorsports.com/images/stories/smbuild/sm_build_20071018c.jpg

http://vitalmotorsports.com/images/stories/smbuild/sm_build_20071018d.jpg

[trinydex]

well it'd be the gap to the center wouldn't it?

[bluevoiix]

it does but it also has to do with how you gap the plugs. each series of plug also has specs for where you're supposed to gap them.


i thought the car has a certain spec for where your supposed to gap them, all im saying is the way you gap the plug shouldnt affect its heat transfering abilities.
heres a quote from ngks website:
It's important to remember spark plugs do not create heat, they only remove heat. The spark plug works as a heat exchanger
by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling
system. The heat range is defined as a plug's ability to dissipate heat.

The rate of heat transfer is determined by:

The insulator nose length
Gas volume around the insulator nose
The materials/construction of the center electrode and porcelain insulator
from what i understand your gap has more to do with your setup:(another quote from ngk)

Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005".

these are just suggestions though

[trinydex]

i've been talking about going hotter and colder on the gap width. because they apparently refer to it in the same way, wider is hotter and colder is narrower, and it is consistent with what was said above about the power of the ignition system above.

[bluevoiix]

ok, just got a little confused.

[trinydex]

no it's good to disambiguate that. people throw those words around a lot, without really clarifying which they're referring to.

[tam@xperformance]

http://vitalmotorsports.com/images/stories/smbuild/sm_build_20071018d.jpg





well it'd be the gap to the center wouldn't it?

Yes, but there'd be no easy way to measure it since the gap is curved (so feeler gauges won't work), and adjusting the gap would also be tricky without some special tools different from regular gapping tools. In actual fact, the plugs come pre-gapped.

I wonder if this kind of plug also allows you to increase the stroke by a couple of mm or use domed/tapered piston heads to increase compression (since they allow for greater clearance so the piston doesn't smack into the plug)?

[trinydex]

yeha i didn't really notice that... if they were flat it'd have been easy

[SpeedElement]

I havent change my spark plugs ever since i purchased my evo its been almost two years and time to replace it. Before i posted this topic i did my search but still confused??. Now what will be a best spark plugs for my evo? ngk? denso? iriduim(sp)?. 1 step colder? two step colder? just go for oem ones?

by the way i dunno if it matters here's my engine set up

20g turbo
gsc s1 cams
ported manifold
tbe exhaust

Thanks in Advance guys


Go with Denso sparkplugs :)

Stock heat range - IKH22 Denso Iridium Spark Plugs. These are pre-gapped.

1 step colder - IKH24 Denso Iridium Spark Plugs. These are pre-gapped.

[Lurk]

Why waste money with Denso Iridiums, when the NGK Iridium IX plugs are just as good for much less money? Stock plugs are NGK as well...

BTW, don't try to gap an Iridium spark plug you'll end up having to get a new one. :)

[Darqnez]

I have gapped plenty of iridiums, you have to be VERY CAREFUL, use feeler gauges and not those coin shaped plug gap gauge things and use a magnifying glass when checking the gap, be very careful to not let the feeler gauge arm slide against or apply any pressure to the tip. Also when your done, look over the tip very carefully in the magnifying glass to check for chips or fractures.

I haven't ruined one yet.




Why waste money with Denso Iridiums, when the NGK Iridium IX plugs are just as good for much less money? Stock plugs are NGK as well...

BTW, don't try to gap an Iridium spark plug you'll end up having to get a new one. :)