Which Spark plug for 500hp ?

[cobrAA]

I know Skym said that for every 100hp you should go one step colder, is that right? so if GTR are -11 oem at 300hp, I should go -9 then?

Is there anything else I need to consider to the equation? Sorry for beeing a bit newbs on this one but I have to order them quick and don't have much time to do research an dfind valuable sources. I need them by friday.

thanks!

[steveo1502]

I used ngk bkr7e in mine just recently, plugs seemed hard to find but I got them at Blackfoot motorsports, they sell dirtbikes but had them on the shelf

[gtrjon]

+1 for bkr7e keep in mind they are copper plugs so will need to be changed more often but great spark for high boost applications

[markdett]

Gap to 0.7mm also!

[cobrAA]

Yeah I heard the gapping depends on the boost your giving to your car, well mine is 22psi.

[steveo1502]

Oh yeah, and there 4 bucks each,I tried a bunch of different gaps, .7 defiantly worked best for me

[malibusst]

BKR7E. part number 4644. any parts store can get them.

gap them to .025 and call it a day.

[Fred-R]

.025=6mm. I also boost at 22psi so i should gap to 6mm? How go you determine the right gap? As jon said: copper plugs worn out quicker, how many km should i change them?

[malibusst]

.025 isnt 6mm.

its 0.635mm.

i changed them every 10,000 kms.

[Fred-R]

.025 isnt 6mm.

its 0.635mm.

i changed them every 10,000 kms.

You're freakin right man! ok thank you!

[gezed]

try looking for them in the states, you can get them in bulk for about $1.70 each when u buy a set of 30+

[frankiman]

i've been using NGK copper racing plugs, R5672A-8, for years with great results, gapped at 0.030 on 17-18 psi
and at 3$ each, can't say no

i change them every year

[Skym]

I know Skym said that for every 100hp you should go one step colder, is that right? so if GTR are -11 oem at 300hp, I should go -9 then?

Is there anything else I need to consider to the equation? Sorry for beeing a bit newbs on this one but I have to order them quick and don't have much time to do research an dfind valuable sources. I need them by friday.

thanks!

Not what I said, what NGK said.

Stock is NGK PFR6A-11 on RB26 for 280ps. Actually it's said to be closer to 311hp at engine.

From what I understand, the 6A is heat range and what the number, letters mean is here -

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqcode.asp?mode=nml

NGK recommend every 75-100hp you go one heat range colder -

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqmodified.asp?mode=nml

More info on heat range of sparkplugs -

http://www.ngksparkplugs.com/tech_support/spark_plugs/index.asp?mode=nml

Also if engine runs lean (colder heat range) or rich (hotter heat range) due to ECU tune, you change heatrange.

Also there's other things to take into account like climate, etc that's mentioned here -

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/index.asp?mode=nml

You gap sparkplugs down due to weak ignition system, as explained by NGK on how much to gap sparkplugs -

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqpregap.asp?mode=nml

You can play with coilpack dwell settings on ECU to increase spark, but it reduces lifespan of coilpacks.

Another solution is HKS Twin Power DLI (same as what they run on their 7sec R33GTR dragcar) to increase spark with stock coilpacks -

http://www.hks-power.co.jp/en/products/electronics/ignittion/twinpower/index.html

Note the increase in spark output in photo's.

Motec ECU can run an upgraded ignition system that's used on high hp import dragcars, but is for competition use only. From what I understand, from what Motec tuner said, it struggles to give a smooth idle or something like that and not good for stop and start traffic. He suggested stock coilpacks are better for street use.

[cobrAA]

Okay by looking at NGK, I know I had the V-power. Seems like Iridum IX is their best spark plug,

frank, I found your part number, its BKR8 IX

[frankiman]

R5672A-8 is R5672A-8 not BKR,
its a racing copper plug