Spark Plugs

[The Dan]

Ok I cannot go any further without clearing this up once and for all.

I constantly see people posting threads about spark plugs, their heat ranges and gap specs.

3 things -

1: Only use the spark plug listed for your vehicle or a derivative of that ie. Iridium etc.

2: The heat range from FACTORY is 5 on an NGK plug for every R3* skyline except the GTR's and R34 NEO 6 which use a 6

3: The FACTORY gap setting for these spark plugs is 1.1mm

Why the hell do I keep seeing people talking about regapping their plugs to 0.8mm. Why don't we all jump on the band wagon and gap our plugs to 0.8mm instead of the factory spec of 1.1mm because we saw a thread about it from some guy on the other side of the country. The whole idea of setting your gap is to create the LARGEST POSSIBLE GAP without losing spark efficiency.

Next is the heat range.....Nissan spend millions on product development each year....why? So some backyarder can mess with the settings? NO! The heat range is there for a reason, go too hot or too cold and you will foul the plug and the car will run like a bucket of shit. Probably more so because you have set your freakin gap to 0.8mm aswell coz Joe bloggs told you it was a good thing to do at the time. But I see people running a heat range of 7...why would you jump 2 whole heat ranges? Most of the time you only have a stock standard car anyway, cept for the pod and zorst

Bit of a guidline here for newcomers. PAY ATTENTION TO THIS PART.

The only reason you need to reduce the gap of your spark plug by THAT much is if you are running large amounts of boost etc. The reason for this is because cylinder pressure has exceeded manufacturers specs and therefore there is more current required to arc across the same gap....and because we cannot amplify our spark at will, we require a smaller gap so less effort is required to arc across it. Just a bit of a general guideline - If you are running 12psi or less, you shouldn't need any less than 1.0mm spark plug gap. Running 12-16psi ~ 0.9mm gap and 16-20psi ~ 0.8-0.7mm gap. Of course there are other variables but we won't get into that right now. The whole point of this is to educate some people so they don't just 'do what everyone else does'.

As for the heat range, you should have no need to run such a cold plug as a 7 unless aforementioned cylinder pressures GREATLY exceed manufacturers specs. Set the gap and the heat range to suit your application!

By running a smaller gap than required you will not only LOSE HORSEPOWER but you will also effectively cause the coil packs to develop more heat.

By running a heat range that is not suited to your application your plugs will foul quickly, causing the car to idle rough and not combust the fuel/air mix effectively, thus LOSING HORSEPOWER.

Thank you for your time.

[TTT]

That’s very good mate.

But most R32’s are 13-17 years old.

Most R33’s are 13-9 years old.

The coil packs are equally old.

If not already done, the most common mod people to is exhaust, filter, and 2-3 psi more boost.

This almost ALWAYS causes misfire and spark break down issues.

And instead of spending $600 odd dollars to buy Splitfire Coils, people go buy one range cooler and 0.8mm gapped plugs for $24 and $5 roll of electrical tape and do a cheap fix.

If you think that they are loosing power from this then look at it this way.

They have 2 ways of resolving the misfire issues.

1.) go back to stock boost and no mods so they can run 1.1mm gapped plugs and 5 heat range.

2.) Buy new coils packs for $600 odd dollars to get around the misfire problem when increasing boost and power.

Option one is crap and defeats the purpose of having a turbo charged skyline,.

Option 2 is stupidly over priced for 99% of people with skylines.

So when “I” keep repeating myself on every single misfire thread to go change the plugs to NGK BPR6ES-8 plugs and spend half an hour to tape up the coil packs, I am doing so with the knowledge that this will fix the misfire problem 99% of the time and cost the person $30 which is the same as about quarter tank of fuel these days.

Now – Please tell me how much power is lost by going from 1.1mm gap and heat range 5 to 0.8mm gap and 6 heat range?

Does it even register on the dyno?

If someone like BU5TER came on here with a misfire problem do you really think that I’d suggest the same $30 solution?

I wouldn’t know what to suggest.

He’s put 10’s of thousands of dollars in to that car/engine package.

I’m sure that his spark/fuel/air setup is just right.

But like I said, a MASSIVE majority of skyline owners are in MILDLY modified skylines.

And the smaller gap and tapped coil packs fixes the issue.

All you’ve done is come here and blabbed your mouth about why it’s the wrong thing to do..

How about now posting your solution to the common misfire problem when boost is increased on these RB engines?

[Guest Rotary20B]

Well I had a pod and changed exhaust, guess what.. misfire straight away, never misfied before

Just finished installing BPR6ES-11 plugs, gapped them down to .8, perfect, didn't worry about taping the coils as I couldn't see anything wrong with them

Car now pulls strong all the way to redline

[Cubes]

I'd have to agree GTST and rotary 20b.

I developed a slight flatish feel on boost with a little miss when running the std plugs 1.1mm gap as soon as I threw an exhaust on ~150,000km's ago. The exhaust rose boost to 12psi that tapered off to 11psi by peak.

The bloke who worked on my car back then said... "Drop a set of copper ngk's in with a 0.75-0.8mm gap and it will fix your problem* He handed me a set of BCPR6E plugs. (BCPR6EY I think they were called back then)

They worked perfectly and it didn't loose any power.

This was ~4.5yrs ago and almost 150,000km's.

I've only recently dropped in a set of BKR7E plugs in as upon inspection the 6's were cooking a little.

Yes I was a little concerned with the height of the plug (BKR7E's being a tad smaller) but upon inspection there's plenty of head room.

Now do the 7's foul... They haven't yet, I drive the car slow... 2000-2500rpm changes everywhere with the 'occasional' squirt. I get around 470km's a tank driving in this manner, hit the open road for 30mins to see the oldies down south and that tank will see 500km's. Drive it hard through the hills and have a tank of up on boost everyt time I accelerate and I'll see ~400-430km's.

3lit3 32, I wouldn't be too concerned with the theory... Its one of those things; raise boost from factory on a rb20/25det and you need to drop the gap and possibly run a cooler plug depending on power being made.

As it turns out my std coils have decided to start popping a little (~150,000km's travelled by me with 60,000 something km's on the clock when I bought it), splitfires will be on their way soon. I'm curious as to if I'll be able to run a larger gap but from the experience of others running splitfires... I doubt it...

[The Dan]

Very good, all must be well.

But you are only band-aid fixing the problem. If your coil packs are failing - replace them. If your tyres are bald - replace them. If your brake pads wear out, guess what - replace them.

I'm not blabbing my mouth about it being the wrong thing to do. Every second thread is about spark plug gap and bloody heat range questions. All I'm trying to do is stop people jumping on the band wagon to regap and change heat range of their plugs. I have customers with virtually standard cars ask me all the time whether they should do these things and the answer is most definately no....unless you have done some, at least, mild modifications - there is no reason for the ignition source to be insufficient as the coil packs are made to outperform their requirements from factory. Sure, when they get as old as they are you are bound to have some problems with them. And if you are so sure of this apparent 'common fault' then why do you direct people to just tape up the packs and reduce the gap. What happens when the coil packs fail almost completely, what are you going to tell everyone? reduce the gap to 0.2mm, run a heat range of 9 and put 2 rolls of electrical tape round each pack? That shit is just dodgey.

There is nothing wrong with re-gapping your plugs to 0.8mm, go for it. There is also nothing wrong with changing from a heat range of 5 to a 6, because as I previously stated, it was the jump of 2 heat ranges that I was referring to. But you are still missing the bigger picture here. I am not goin off at anyone but merely trying to educate some poeple to the fact that just because you have a skyline with an exhaust and pod filter, doesn't mean you have to regap your plugs. If you need to regap them with literally no mods like this, then you obviously have another underlying problem which requires attention.

[Cubes]

I see exactly where your coming from, there has been a small influx of spark plug related threads over the last few weeks.

I believe every thread I've posted in and suggested what heat range or gap to use I have taken note of what mods the member has before making a suggestion.

I even believe in one thread I suggested approximate power levels where to step up to the next heat range based on where cars here in Adelaide have had to step up and general spark plug reading.

but yes.. i edited my post above.. My coil packs are now finally on their way out.

[HRthirtyone]

i have run everything from a 5 - 7 heat range, and used copper, platinum and iridium. 1.1 always eventually misfires on anything over 11psi. for a my old rb20, standard with r33 turbo, 14spi and cooler and zorst the bcpr6es with .8 gap never missed a beat.

my new engine with bigger inj, cams and hks turbo etc. runs bcpr7es gapped to .8 and only because i read these threads. Im starting to wonder if the 6 heat range would have been sufficient, because the 7 heat range plugs foul easily with a rich start mixture on the microtech....

[Busky2k]

Maybe you need to lean out the cold start enrichment a bit HRthirtyone. I've run 7s for years now and none have ever had problems with fouling up.

[R32-PSH77]

Can i suggest to maybe delete the Spark plug thread discussion page. and perhaps setup a similar page to the dyno result page for example:

Engine: RB20DET

Coil Pack: Stock

Plugs: BPR6RES-8 (Heat range 6 Gapped to -8)

Boost: 14.7 (1 Bar)

Mods: T3/T4, 3" turbo back, Pod, Power FC

Previous plugs: PRA5A11 , BCPR6EIX-11

Problem: Both set of previous plugs were gapped at 1.1 and causing misfiring.

Solution: New plugs at .8 gapped stopped all misfire.

Just a suggestion.

Then people can find someone with similar mods, and attempt to try the same set of plugs. i know i have read alsmot every spark plug thread to gain knowledge and there always ends up with two or more people arguing. my problem was fixed by reading numerious posts by cubes suggesting the current plug im about to install.

Having said that. daniel you right. it is a cheaper fix to a bigger problem. But for now. why not let it be known to everyone that perhaps the coilpacks are about to pack it in and to start saving. It would be better for someone to be able to run around without misfiring and have smooth idle/ and no misfiring while maybe we all saved to buy some replacement coil packs.

Just an observation. dont wanna pick sides. just stating my personal opinion.

Thnx, Adz

[Guilt-Toy]

I would like to add somethign to this thread.

I first got my skyline 5 years ago and when running stock boost i had no problems. I then upped the boost and got the missfire.

Then i gapped the plugs to .6 and off i went. Car went great! Band aid fix for stuffed coils you say ??

5 years later and after 10's of thousands of $$$ spend on my setup GUESS WHAT ? i still use the SAME coils.

So 5 years later i am still using the same coils and i am able to run them on 1.1 gap when before with the rb25det i had to run .6 .7 for it to be right.

I think it has more to do with the boost pressure AND air flow going through the engine - it might have something to do with smaller turbo's pushing high boost without much air flow causing the issue.

IF my coils were stuffed then why are they STILL running now with a extra 150rwkw on the standard 1.1 gap ?

[mad082]

Next is the heat range.....Nissan spend millions on product development each year....why? So some backyarder can mess with the settings?

nissan also tuned these cars to run on a higher octane rating fuel than we have, so going to a colder plug will stop a bit of pinging.

[sewid]

I think you're all right. Let's have a cup of tea.

[sewid]

Personally I gap my plugs to 0.8mm but I admit i feel a little stupid doing it. Particularly when it says not to gap iridium plugs at all ever since you probably destroy them quite easily if you get it even slightly wrong.

No problems so far running about 18psi. I am now running new coils so i'd probably at least try standard gap for my next set of plugs.

[mad082]

Personally I gap my plugs to 0.8mm but I admit i feel a little stupid doing it. Particularly when it says not to gap iridium plugs at all ever since you probably destroy them quite easily if you get it even slightly wrong.

you should be able to buy them with a 0.8mm gap.

personally i don't agree with running iridiums. nissan recommends them for longer life, but my copper plugs lasted as long as the iridiums did, and the cost for 6 copper plugs was the same as 1 iridium.

[MBS206]

You have one small problem with your idea on running manuafacturers specs.

The car was built to run in japan. They have a different climate to what australia has. Hence you need to change your heat range and gap.

[Devils_Advocate21]

Talk about bringing up an old thread from aug 06 Let it go people?

[R32-PSH77]

Sorry bout bringing it up.. i didnt even realise how old it was.. lol.. as usual i was researching spark plugs and found this thread.. i hold dans opinion high as well as others like cubes.. so it was interesting to see what they both had to say.

peace

[The Dan]

It doesn't matter about the climate. Whether it's 0 degrees ambient or 40 degrees ambient...the engine is designed to run between 82-88 degrees celcius.

So it doesn't matter what climate you are driving in...the engine will operate the same way within those given temps. Fair enough the octane rating will make a minute difference but given the factory tuning and the fact that most people have reset their computers already, I don't think it would pose that much of a problem.

As for running those coils 5 years later...did you change your fuel pump or filter in that time? If so then that may have been your problem all along.

Much of the point I was trying to make has been lost and that was....The ignition system is designed to run with a gap of 1.1mm. Do you think Nissan slapped the engine together, gapped the plugs to 1.0...said "good", opened them up to 1.1...said "good", gapped to 1.2mm..."oh wait we've got a misfire, let's make it 1.1"?

They didn't design these setups on the border of missfire/blowup

If your ignition system cannot handle a plug gap of 1.1mm then there is some type of problem. I put in the splitfire coil packs and ran 22psi boost with a plug gap of 1.1mm with absolutely no issues ever. That was because I had a decent fuel pump (not some walbro crap coz it was cheaper than the bosch), I had decent injectors which suited the power output I was making, and a decent ignition system. I also had a good intercooler (PWR) which ensured inlet temps never went higher than they should.

Find the weak link and replace it....don't just slap a bandaid over it.

[Cubes]

I put in the splitfire coil packs and ran 22psi boost with a plug gap of 1.1mm with absolutely no issues ever. That was because I had a decent fuel pump (not some walbro crap coz it was cheaper than the bosch), I had decent injectors which suited the power output I was making, and a decent ignition system. I also had a good intercooler (PWR) which ensured inlet temps never went higher than they should.

You are the minority.

Your not running an ignition amp or sorts?

Any one else here able to run a 1.1mm gap with 20+psi?

[T04GTR]

very simple

there modified and not factory spec!!