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Hi thought I would put in my 2 cents worth. This is my experiance and what I was told. A colder plug has a colder spark and producers less power, however it is more conductive and therefore will ignite under more pressure. A hotter plug has a hotter spark, producers more power but is less conductive, therefore wont ignite under higher pressure. A bigger gap provides a bigger spark, which ignites the fuel better and producess more power. However a bigger gap is less likely to ignite under a higher pressure. For example, someone befor said that they put in a spark plug that was running realy smooth at idle and in the lower rev range, but was missing up high. I would say that they have a spark plug that is too hot. Ignite the spark really well with less pressure and will run better than the other plug but wont ignite as well under pressure. Therefore misses up high. Thats why alot of people with close the gap to make it easyer for the spark to ignite. I run an 8 in heat range with a 1.1 gap. When I put in a 7 with a gap of 1.1 I get better fuel economy (almost an extra 100km to the tank) and more response down low. But when I put my foot down and boost gets over 12psi it will start to miss. So the trick is to get the right heat range with the right gap for each plug. I use NGK plug and I use the V-groove. I also use the copper plugs too, I tried the iridium plug but couldn't get them to work for me. I even sent my plugs to melbourne for one of there enginers to tell me what to run, but I went back to what my tuning shop told me to run.

Now I am not saying that I am right, this is just what I was told, and I thought I would add it as I thought it might give people enough of an idea on how to experiment with ther plugs and there gap and there heat range. Anyway hope this helps someone out there.

Decided to try BCPR6E 1.1mm in my R32 GTST w/ 200kw atw & splitfire coilpacks

Previously had 0.8mm gap due to a misfire problem which was fixed with the splitfire coilpacks

1.1mm gives me no misfire at 15psi, however will update once i get car properly tuned and pushing more boost (18psi~)

This has probably been answered - if there is no gap number on the part code does that mean there gap is 0.8?

I'm running 'BKR6E' (no gap number on the box so I assume its 0.8?) wasted-spark coil pacts, 220rwkws 13psi, auto box.

Edited by daxter
Anyone experienced any issues with running BKR7Es on cars doing over 250kw?

I ran the bcpr7es which is virtually the same thing, just a slightly longer body. Power wasn't what prompted the change (as it made 250 with the 6's in it) it was boost above 17psi when a miss started to creep in.

This has probably been answered - if there is no gap number on the part code does that mean there gap is 0.8?

I'm running 'BKR6E' (no gap number on the box so I assume its 0.8?) wasted-spark coil pacts, 220rwkws 13psi, auto box.

yep -11 is a 1.1 gap, no - is a .8

meh now im confused, everyone seems to say a different thing, people saying use bkr7e's on an rb, people saying not to, to use BCPR7ES 0.8 also had someone tell me to use the PFR range of NGK sparkplugs.

engines an r32 spec turboed rb25de.

  • 1 month later...

Just thought I'd let you all know, I recently upped the boost to 12psi on my R33 S2 (190rwkw on the dyno!) it was running ok for a few weeks and then developed a bad miss at about 4-5000rpm or so under load (half throttle plus)

Everyone said and everything I read said "coil packs" ($600+ for replacement splitfires!) so I taped them up to test the theory... still no good...

Then I replaced the old platinum plugs (factory?) that looked to be in great condition except the gap (orignally 1.1) must have been out to 1.3 or more as the electrode had worn down!

I replaced them with NGK V-Power BKR6EYA (no number means 0.8mm gap) plugs from Bursons - $24 for 6!

Problem solved, the car has never gone better :)

BTW 190+rwkw: stock ECU, stock turbo, stock coil packs & fuel system! R34 sidemount (fan-forced), CAI, pod, 3" X-Force turbo back zorst, 12psi!

$1500 worth of DIY mods :)

Edited by Checkbuzz
I would be using BCPR7ES with a .8mm gap. the 11 denotes a 1.1mm gap. too big if you are running anything other than a completely stock set-up.

gapped down to .08? as thats what ive now done

i see the s means standard type on the plug lettering break down - mine does not say "s" on the plug body.................... why not?

Edited by DAS KAMU

quick question. i was using bcp6es-11 gapped down to .8, have been for ages with no troubles at all on stockish motors. put a gt30 and other stuff on my 25 and just before the tune put in some bkr7e's after reading about them on here. car didnt make as much power as it should however thats probably caused by other things. car was running fine at first and allways runs fine on cooler days/nights, but when its slightly warmer it misses pretty hard occasionaly under full load on high boost (17psi). could this be the colder plugs? or something else? have splitfires which are near new, good condition ignitor, only think that hasnt been changed is the coilpack loom.

People underestimate the power of a colder range sparkplug, I'm definately a fan esp on n/a + turbo 30's.

I run dirty old 30e+t with bcpr7e-8's, with upgraded ignition (bosch GT40) with a 1.1mm gap boost above 12psi was missfiring. At 8psi, no issues, pulls strong and smooth.

Question though, should you be running the best gap you can achive without missfires? or does it pay to decrease the gap a little extra to achieve a stronger spark? (or is it sumply a case of, if the spark can jump the distance, its no difference).

Also, anyone know anything about indexing plugs on the old twincam rb? I've got an high compression N/A custom RB30DE, and an RB25DET, you generally pick up a few kw from indexing, and i like having all cylendars equel. I currently have the N/A plugs facing between the intake ports and the turbo facing between the exhaust ports.

Anyone know?

  • 3 months later...

Hey guys,

Arg feel so stupid asking this but I couldn't get any confirmation by searching so, gotta ask I guess. Ok basically I had the RB20de engine (N/A), decided to turbo it for sh_t's & giggles lol, using the stock RB20det parts and only running 7psi.

Here's the question, RB20de and RB20det engine same plugs right? I'm almost positive yes, just wana clerifiy.

Thanks everyone.

Cheers :laugh:

People underestimate the power of a colder range sparkplug, I'm definately a fan esp on n/a + turbo 30's.

I run dirty old 30e+t with bcpr7e-8's, with upgraded ignition (bosch GT40) with a 1.1mm gap boost above 12psi was missfiring. At 8psi, no issues, pulls strong and smooth.

Question though, should you be running the best gap you can achive without missfires? or does it pay to decrease the gap a little extra to achieve a stronger spark? (or is it sumply a case of, if the spark can jump the distance, its no difference).

Also, anyone know anything about indexing plugs on the old twincam rb? I've got an high compression N/A custom RB30DE, and an RB25DET, you generally pick up a few kw from indexing, and i like having all cylendars equel. I currently have the N/A plugs facing between the intake ports and the turbo facing between the exhaust ports.

Anyone know?

indexing the plugs is definitely a good idea. not sure how much gains you will get but it certainly wont do any harm.

and yes you should be running as much gap as you can without missfire, maybe reduce it a little back from that point for a small margin of safety. the bigger the gap the longer the spark so the better things go. but of course if gap is too big spark can't jump the gap and you get it arcing out and missfires.

i have a question about indexing plugs. if you had to actually use a washer to index the plug, don't you run the risk of negating any gains due to the fact that you are moving the tip of the plug further from the mixture? i know that it is all compressed when the spark occurs, but wouldn't you want the tip to be a bit further into the combustion chamber to give a slightly more even and quicker burn?

i have a question about indexing plugs. if you had to actually use a washer to index the plug, don't you run the risk of negating any gains due to the fact that you are moving the tip of the plug further from the mixture? i know that it is all compressed when the spark occurs, but wouldn't you want the tip to be a bit further into the combustion chamber to give a slightly more even and quicker burn?

Spark plugs have a fairly tight thread, the difference between a plug facing one way or the other is a bee's dick. Also, copper is an incredibly soft metal, if you remove the factorry spark plug washer, and use a slightly thicker copper washer (you have to account for the squash in the copper, which will bring it about to where the stock washer would have been) you then tighten until the plug is firm and faces the right direction, due to the soft nature of copper you can generally get at least a full turn out of it which is the same torque, but just squashing the copper.

I love even cylindars, all identical compression, identical flow injectors and identical facing plugs, makes for near identical combustion, meaning you can push the limits more in terms of a/f mixture and ignition timing. Tuning how you should be tuning, using a pyrometer, not guesswork listening for detonation and over fueling using an wideband.

People underestimate the difference between cylinders, with some being lean, and burning different, added exhaust restriction (meaning hotter) could be the difference between popping your engine, or way better fuel economy, or alot more power - i.e. all cylendars are happy with 40degree's ign, except one, which pings after 25degree's, because it is both lean, and exhaust restricted, meaning richer fuel mixtures and less ignition timing and/or boost = alot less power, less drivability and worse economy.

offtopic anyway :blush:

hmmm....

What is the difference between a "BCPR6ES" and the "BKR6E-11"?

other then the gap difference, they are both copper plugs with the same heat range correct? I bought the BKR6E-11's after i found my local shop didnt have the normal plugs in stock.... however, the BKR6E's have the same number as the iridium plugs without the prefix, and were listend under the performance column. can anyone shed light on the diferences?

Hello there ...

BCPR6ES ->

BC = TREAD DIAMETER = 14mm

PR = PROTECTED INSULATOR + RESISTOR

6 = HEAT RANGE

E = THREAD LENGTH = 19mm

S = STANDARD SPARK PLUG TYPE

BKR6E-11 ->

BK = THREAD DIAMETER = 14mm

R = RESISTOR

6 = HEAT RANGE

E = THREAD LENGTH = 19mm

11 = SPARK GAP = 1.1mm

So the only difference between those 2 is that you have a protected insulator type (whatever this is?) and a standard gap as opposed to 1.1mm.

I hope this helps :blink:

Cheers from London,

Andrew

Just wondering if anybody has ever tried the spark plugs with dual electrodes (in the picture right) (do you have them in OZ at all?)

I use them in my motorcycle and it is definitely a huge improvement over the standard plugs.

Of course I don't know about the Skyline, but I will give it a try ..

Cheers from London :P

CLick here for the picture ...

Edited by Torques

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