Spark plug heat range

[Genie47]

Been doing some thinking. I have this hunch your FC is indeed tied to your choice of spark plugs. Specifically the heat range. If you are the urban type driver, more jams, more congestion, more stop-start than usual. Hotter plugs should be used. 16 range (Japanese) or 5 range (Euro) should be used.

 

If you are more of the highway cruiser, then colder plugs are better. 20 range (Japanese) or 6 range (Euro).

 

Anyone out there got some arguments to destroy this hypothesis?

[Trex101]

Well my plugs are burning much much cleaner when using hotter 5 plugs than heat range 6 plugs even though my manual states my stock plugs as NGK BKR6E-11

[Westwind]

If I remember correctly, spark plugs also serve to dissipate heat from the engine. Colder plug dissipates heat faster. Hence a colder plug is often used in an engine with higher compression or car which travels long distance frequently.

 

You are right to use hotter plug for short distance or city driving. It reaches its optimal or self cleaning temperature earlier/faster. Engine using hotter plug has a shorter warm up time in the morning from what I observed.

[Vtim]

actually, the engine is already design to use certain heat range of plugs so, FC should be only depend on your driving pattern. As for me, it's my HRF that controls the FC

 

NGK 5 is equal to Denso 16, both are Japs ley

[Orixy]

Hehe... found this interesting discussion when I was searching for some info on effects of using a hotter plug.

 

 

 

Like to ask the gurus:

 

 

 

>> The use of a hotter plugs (NGK 5[hot] vs 6[cold]) is better for city driving. But is this true only for stock cars with no mod? For example, adding a piggyback ECU to advance the ignition timing is a common mod to gain power, but advancing ignition timing also increases engine combustion heat - as indicated in NGK's webby : http://www.ngksparkplugs.com/tech_support/...ng.asp?mode=nml

 

 

 

So in this case, a hotter plug is not recommended when a ignition is advanced even though it is better for daily city driving?

 

 

 

 

 

>> Also heard of some ppl purposely using plugs with a longer tip (eg. plugs meant for some Hondas are known to have a longer tip) so that the combustion can be more complete due to fact that the tip is sitting "deeper" in the cylinder. Is this true?

[Genie47]

Heat range of the plug is dependant on many factors. All of them mentioned in your post affect the selection. Rich fueling, ignition advance, type of fuel. Stick with the manual.

[Dwoon]

I've used heatrange 6 & 7.... like no diff leh....

 

Now gonna try 8. Got a set of NGK R7119-8 for sale and I'm gonna try them out. Hope they don't cause any issues.

 

BTW, between platinium & Iridium, which is actually better? Because the R7119-8 are Platinums and they actually cost so much more than the Iridiums when I did a search. Both are fine tip.

[Cyberet]

hmm.. tried both 16 & 20, the difference is there, but minimal, i get slightly better FC for 16 when driving in singapore. in .my, its WOT most of the time

20 plugs aren't as "white" as "16" when i take them out for visual inspection.

 

hmm.. but cng burns hotter right? but is it hot enough to need a cooler plug?

Edited May 21, 2007 by Cyberet

[Orixy]

Got a spare set of 5 heat range NGK gpower plat so tot of using them but my engine is speced to run on 6...

[Cyberet]

my engine is one that requires a "extended" tip spark. KJ16CR-L11

Iridium equal is IK16L

 

http://www.globaldenso.com/PLUG/config/index3.html

 

http://www.globaldenso.com/PLUG/search/zip/singapore_4w.zip

Edited May 21, 2007 by Cyberet

[Orixy]

hehe... wont try this risk of cos!! :)

[Genie47]

Yes, Pt tips cost hell a lot more actually. Go for Pt if they are cheaper than Ir. An expensive Ir tip plug means the seller is trying to fleece you.

 

If there is no difference to you, that means your car has not gone through enough mods that demand a heat range change.

[Genie47]

CNG indeeds burns a lot hotter and drier. Actually I kept my plug's heat range the same as the petrol so to clean it off better. I'm running dual fuel actually so it makes no sense to go colder yet unless I fit in an MSD coil.

 

Anyway, the fueling is already programmed and optimized on these stock copper plugs.

[Genie47]

You can try them out. The main problem you will experience is predetonation. Hot plug tip = glowing hot matchstick head to explode the fuel/air mix.

[Fitzy]

My manual say to use heat range 5, what if i use heat range 6, will i encounter any prob?

[Genie47]

Your plugs will be colder so there will be fouling. The heat range makes the plug attain a certain temperature that allows it to be hot enough to burn of carbon (self cleaning) and yet prevent detonation from being too hot.

 

Explains why some cars don't like Bosch Super 4 or some multiground plug. They have more metal (more than 1 leg) and these things actually retain heat.

Edited May 21, 2007 by Genie47

[Fitzy]

I'm driving Altis and planning to change to NGK iridium BKR6EIX-11. Currently on stock BKR5EYA-11. Some ppl say BKR5EIX-11 too hot for altis but at the NGK website, the cross referece guide showed BKR5EIX-11 the right plug. I'm confuse if i should stick to 5 or 6.

Edited May 21, 2007 by Fitzy

[Dwoon]

Yes, Pt tips cost hell a lot more actually. Go for Pt if they are cheaper than Ir. An expensive Ir tip plug means the seller is trying to fleece you.

 

If there is no difference to you, that means your car has not gone through enough mods that demand a heat range change.

 

Guess for a set at SGD60 which is being hogged off.... I'll just get them and try out. (online websearch shows they cost like US$35 a piece. )

 

So far, all my plugs (6 & 7) have come out at 25K km... they don't show any carbon fouling but neither are they white.... so dunno if the heatrange I'm using is correct.