modified RB26 spark plug help

[cbileske]

I read somewhere on here that bk7re would be the plug to get, gapped at .025 (.635mm)
Car has fouling issues and misfiring in low rpm, I am running 20psi. the engine has new splitfire coilpacks.
should be running a larger gap? Or different plugs?
Thank you

[NismoS-tune]

Is it tuned? What fuel are you using? 20 psi with what turbo (300whp with stock turbo or 450whp with -5s)

I run Copper ngk race plugs ($2 each NAPA #4091) at 1mm gap and have 300whp no problem.

I think If you're misfiring at low rpm, you might have too cold a plug (7 isn't so bad though...) or tune issues.

[Skym]

The reason for gapping sparkplugs down to 0.8mm (stock is 1.1mm) is stock ignition system has weak output (weak spark with sparkplugs) which causes a missfire at higher rpm. When fit a stronger ignition system (LS coilpacks as one example or HKS Twin Power with stock ignition system) you can widen the sparkplug gap to 1.1mm.

NGK PFR6A -11 (-11 = 1.1mm gap) is stock sparkplug and go one heat range colder (PFR7A), regap to 0.8mm when cylinder temps rise due to leaning out A/F ratio (intake, exhaust mods).

Sparkplug heat range is changed every 75-100hp or when engine is running leaner (colder tip) or richer (hotter tip).

Read sparkplug tips to figure out what is happening inside cylinders -

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

[Dragon Humper]

I'm leaning towards tune. A modern engine doesn't foul plugs or run like crap just putting around unless the O2 sensors are buggered or the tune is poo.



Jon.

[Skym]

One problem is probably causing the other.

The popping from exhaust would point towards a o2 sensor being lazy thus making engine run rich longer, or too small sparkplug gap.

If engine is misfiring, stock ECU can pick that up as engine knocking and switch to knock maps which runs engine rich.

But sparkplug heatrange being incorrect (if engine is running richer due to above problems) can cause the sparkplug tips to foul.

[cbileske]

Its a vipec ecu tune. I did some data logging and sent the tune info to RG to be altered a little bit. I'm also going to replace the plugs and re gap them larger then the .636mm that re now.
With vipec can u make it so it uses the wideband as a o2? So the o2s can be elimiated?
Running -5 turbos with one map at 14 psi and the other at 20psi with water meth.
Always use 94 octane fuel
535bhp

[DRIVER_R32]

Use shell 91 v power or c16 instead. Bkr7e should be fine. Gap at 0.8

[Skym]

I think you can run a wideband in place of narrowband o2 sensor. Also some widebands have a convertor for wideband signal (0-5V) to narrowband (0-1V).

ViPEC ECU shouldn't be able to detect knock, switch to knock maps without an additional knock block (just like Link ECU). But most new stock ECU's (Porsche, etc) can detect knock in each cylinder (using new way of knock detection) and I would think most aftermarket ECU's will eventually have this feature (if they don't already).

One of the o2 sensors would be my guess if not the maps on ECU.

[cbileske]

okay, thanks for the info. When I eventually get home from work, I will play around with it a bit.

[tryingtobebest]

Ok, so I was reading about all the spark plugs all around the internet for the last few weeks! Here is my findings:

I was a strong beliver that NGK racing plugs such as R5671A-10 would be the best choice:



especially that on my 96 Turbo Altima (8-9 psi only) this spark plug was running absolutely with not a single problem for like 60+ K km, with perfect idle rigth at around 800rpm, single ignition coil and obsolete distributor ignition system. The only thing i change it is because it simply wear itself down and start to miss at higher RPM , here is a pic of plug from Altima:



BUT on my GTR i had to change 3 of them in the past like 2000kms!((( May be this is due my own tune on Halltech which run a bit rich on idle and bit lean on top, but it is also maybe because all series of the NGK racing plugs such as:

R5671A-7 (4091)
R5671A-8 (4554)
R5671A-10 (5820) etc.

are NON-Resistor type! And our manual recommend resistor type. (I have not done research here, just stating this info for others)

SO, next thing im going to try is BKR series, and my recommendation according with NGK heat range increasing recommendations would be:

Up to 450hp - Cooper BKR7E (4644); Iridium BKR7Eix (2667)
Up to 600hp - Cooper BKR8E ( ? ); Iridium BKR8Eix (2668)
Over 600hp - Cooper BKR9E ( ? ); Iridium BKR9Eix (2669)

NOTE: The reason i provide Iridium is because in Canada i cant find any NGK existance of ether Cooper 8E or 9E, if someone has the NGK numbers that all major stores have, post it up! The numbers i provide can be easily find but most likely special ordered in any local stores - Auto value, Part Source, Napa, Parts Unlimited even Canadian Tire....

If you have upgraded coilpacks, i think there should not be a problem in running 1.1mm gap, so you can go with:

Up to 450hp - Cooper BKR7E-11 ( ? ); Iridium BKR7Eix-11 (6988)
Up to 600hp - Cooper BKR8E-11 ( ? ); Iridium BKR8Eix-11 ( ? )
Over 600hp - Cooper BKR9E-11 ( ? ); Iridium BKR9Eix-11 ( ? )

You can get most of this sparks from US side but i just can find them in Canada....

If some of the information here is wrong PM me and ill edit it right away!

[NismoS-tune]

I use R5671A-7 (4091), no problems. Your tune is backwards too lol.

[cbileske]

I should be running in the 8 heat range then. According to ngk. I'm pulled the plugs to see what the last little drive shows, they are all running hot. Bkr7e in there right now. Does anyone have a part number for the 8's?

[nick-nismo]

i run bcpr7es, i ran into problems with a missfire at idle with the bkr7e
havn't looked back since i switched

[Blackcossie]

Use shell 91 v power or c16 instead. Bkr7e should be fine. Gap at 0.8

[Dragon Humper]

I run the coldest race plugs there are for our motors, AutoLite. My plugs always look good and have no drivability issues at all. I don't even run 02 sensors, check your tune.





Jon.