Take a look at the bottom of this page in the online manual :-

http://www.300zx.co.uk/tech/manual/manual/ma/018.gif

According to some of the references inside it specifically covers the Australian and Euopean models.

 

It clearly states that the standard spark plug for a TT is PFR6B-11C whereas in my official, printed Nissan workshop manual, that also specifically covers the Australian and European models, it clearly states that the correct plug is PFR6B-11 ????? Can't they make their minds up ?

 

There is clearly more than one edition. I know that mine is the February 1990 edition, but I don't know what the online version is as that page has not been scanned. Incidentally, mine has more pages in certain sections.

 

In the words of Toyah, "It's a Mythtery" !

Hmmm...NGK have the VG30DE for Europe ->97 listed as PFR6B-11 and the VG30DETT as PFR6B-11C.

 

I guess I can find out for sure if anyone's interested (?)

 

Cheers!

 

RobH

 

(back on the forum at home after a hip replacement - boo hoo!)

I concure that PFR6B-11C is stated as the standard plug and having looked in my Service manual late 1992 supplement for series one the same applies and in my 1993 manual for series two the same applies so it would seem PFR6B-11C is the one and also NGK state this in there application book.

 

Also as WARNING no other manufactures plug is equivalent

in design the listed Boch plug has a different sized insulator and longer electrode tip but is platinum though, they work but the self cleaning is poor and sooting up is common

 

(See pic) difference between point A and B was quite substantial sorry for poor quality...auto focaus has it limitations

 

 

Jeff TT

Hi Andy,

 

The PFR6B-11 is an admin error by Nissan! It is the plug for an NA!

Well, sorry to drone on about the third most boring subject of all (after head lights and oil ;)) but all Jap cars seem to come fitted with PFR6B-11, so does that mean they should stick with those, assuming they're running standard ignition maps and decent fuel.

 

Just curious about what people think really ....

Yes Andy your right all imports have PFR6B-11 fitted as standard but as the NGK application book mentions different versions of the same graded plugs are fitted to suit conditioned for where the car (any) was to be marketed, hence the Japanese market cars got plugs to suit their needs and conditions...temperature fuel, quality driving styles etc, etc.

 

In my opinion I always recomend the changing of import plugs to Uk spec ones, it at least removes any problems in the future and in more than a few cases I have dealt with it has cured odd running problems. On this one Nissan knew best

 

 

Jeff TT

Lets take into account here that Jap motor had a speed limiter on it!

 

Even Nissan America acknowledge the admin error of prescribing NA plugs for a TT!

 

List of countries recommending PFR6B-11B

 

Australia

 

New Zealand

 

USA

 

Switzerland, even they broke their Neutrality

 

UK

OK, so now you've got to where I was drawing this conversation. 11B's - where did they come into the mix when Nissan is recommending 11C's. Questions need to be answered ! ;)

 

 

Originally posted by TopLess

Lets take into account here that Jap motor had a speed limiter on it!

 

Even Nissan America acknowledge the admin error of prescribing NA plugs for a TT!

 

List of countries recommending PFR6B-11B

 

Australia

 

New Zealand

 

USA

 

Switzerland, even they broke their Neutrality

 

UK

11B's are the plug Nissan commisioned NGK to make for tuned Z's

 

11C's are for completely stock cars!

 

Irridiums are made for some other car but Denso who are the same as HKS plugs, save themselves a few quid and say they are for Z32's as well!!!!!!!!!

 

If I was paranoid I would think this thread was created to get me going:D

If that's the case then we need to get this documented properly so that people know what's what !

I agree with Topless. I had this conversation with NGK many times during the good 'ol days (when I had my Z that is).

 

An NGK tech. rep. told me that the 11C is the correct plug for the UK TTZ. Its a little shorter if I can remember and is more biased towards "improved emissions" than the 11B.

 

Nissan in the US commissioned NGK to come up with a "better performance" plug, or as the story goes, a plug that reduces the chance of detonation, hence the 11B. If I can remember, its a little longer and thus further away from the head.

 

11's on their own are DEFINITELY N/A plugs no matter where you are on the planet.

 

11Bs are now considered the "best" plug, particularly for modified Z's, which is where Nissan were coming from. They expected owners to increase the HP out of their cars!

 

Iridium plugs are better still...oh, and FFS, never put Bosch plugs in your Z as I had nothing but problems with them.

 

Andy

Originally posted by Anders UK

Iridium plugs are better still

 

Andy

 

 

Andy,

 

Completely agree with you apart the above point, if you look at the reach of the 11B plug it is much longer than the 11C, if you look at the reach of an Irridium it is even shorter than the 11C, so much so it is virtually hidden by the spark plug shroud in the chamber!

 

If someone wants to send me an old Irridium plug, I will take some photos of all three plugs sitting in the chamber, as I have a couple of stock heads at the workshop!

Originally posted by TopLess

Andy,

 

Completely agree with you apart the above point, if you look at the reach of the 11B plug it is much longer than the 11C, if you look at the reach of an Irridium it is even shorter than the 11C, so much so it is virtually hidden by the spark plug shroud in the chamber!

 

If someone wants to send me an old Irridium plug, I will take some photos of all three plugs sitting in the chamber, as I have a couple of stock heads at the workshop!

 

Ok my point..............................

 

Had Stock plugs running 1 bar of boost,the gaps in those plugs were badly worn after 30k,they will do 60k running stock boost.

 

The irridium plug will stand more heat so that means you can run more boost.

 

When we compared the length of the stock against the HKS plug,it was around 1mm Big deal!

 

So my conclusion is If you want to run stock boost,then fit stock plugs,or to put it another way,go and fit stock plugs and run 1.5 bar then see how long your engine will last.

 

 

:rolleyes:

PFR6B-11B aren't stock plugs Macca!

 

They are about 4mm longer then 11C's (the stock plug) and therefore 5mm longer than Irridiums!

 

Maybe one of the reasons your plugs were badly worn was detonation (there are some types you can't audibly hear) or preignition, causing damage and/or overheating in the chamber!

 

The reason they have a longer reach on them, is that as you increase the boost there is more turbulence in the chamber and obviously a stronger need for the spark to occur in the middle of the combustion chamber!

I tend to agree with both of you to a point.

 

Sure, the iridiums are not as far away from the head as the 11B's but they are still a more superior plug.

 

I'm an old fan of copper plugs, basically because copper is a better conductor than platinum and in theory provide a "stronger" spark. The problem is that copper plugs degrade very quickly on turbo charged cars and struggle under high boost conditions if the gap isn't perfect, and I mean perfect.

 

I've messed around with plugs on a number of turbo'd cars and found copper plugs (when PERFECTLY gapped) to provide a "cleaner" burn and generally smoother through the rev range. Also, I averaged an extra 2-3 mpg on copper plugs. Are they worth the hassle? Only if you have the patience to play around with different gaps and are prepared to change them every 5-6k. Other than that platinum are a lot stonger and forgiving when it comes to tuning and raising the ol' boost, but they're not perfect.

 

Iridiums. IMO, these are the dogs... Conductivity like copper, stronger that plats and able to hold a superior spark under the most severe conditions (heat, obscene boost, you name it). I have never heard a bad word about them. Only good. I know of many people who noticed marked improvements over plats, particularly in high boost applications, curing high-boost misfires and so on.

 

Those of you with stock cars - stick with plats. Go high boost - try the iridiums and you'll never turn back.

 

Andy

Sorry Anders,

 

The experience of most people on TT.net says otherwise, and they are big boost/bhp cars, sure I agree the materials they are made from are superior! But it is of no use if they deliver the spark at the wrong location in the chamber!

Fair point.

 

I was talking about high perfromance cars in general and not just the Z. Its a shame they haven't perfected iridium plugs for the Z!

 

11B's it is then...

FWIW, i had a chat with NGK technical dept & they also said that the Iridium plugs they supplied wasnt suitable for the zed & that the Platinum plugs were better anyway

I've just ordered a set of ZFR7F-11 coppers to try in mine for now.

Part of the reason irridiums are better is because the narrower diameter electroder provides a stronger spark, so the spark is strong enough to cross the gap in a dense (high boost) charge. The problem I'm thinking is if they're still 6 heat range you're going to be prone to detonation due to the electrode tips being too hot (the PFR6B-11C's I've got in now show strong signs of overheating).

Also, I believe the length of these plugs is the closest to PFR6B-11B you can get I'll post the measurements vs PFR6B-11C for comparison when I've got them.

Think I'll have to close the gap down on these - was going to start at 0.8mm - any ideas anyone??

I know some US tuners use PFR6B-11B as a colder plug, but remember their standard plugs are a 5 heat rating (fuel quality???)

The japs seem to recommend the ZFR7F

Fitted these,must say the car runs better than it ever has.

 

http://www.hksusa.com/products/more.asp?id=730

 

I would NEVER change them for anything else on the market!

Originally posted by TopLess

 

Maybe one of the reasons your plugs were badly worn was detonation (there are some types you can't audibly hear) or preignition, causing damage and/or overheating in the chamber!

 

 

No It was down to running a higher level of boost through them!

The plugs that came out were the right colour.

Hi

 

Just been reading the chat about plugs. Most of you seem to have TT's and lose me on the technical stuff for those babies.

I would like to know what are the preferred plugs for a N/A Zed import with no mods.

 

Thanks LOCKY

Quite straightforward, PFR6B-11

Thanks Andy

 

LOCKY:)

There seems to be two lines of thought!

 

1. The irridium can take more heat, therefore it will last longer, but it delivers the spark at the wrong point in the chamber, potentially having a loss of bhp, fuel economy and increasing the risk of detonation, along with an increase in chamber temperature!

 

2. The 11B that will deliver the spark at the right point in the chamber, giving greater BHP, fuel economy, cooler chamber temp, but there maybe a greater increase in the wear of the plug(alledgedly) but I think most people on here who run larger bhp would check their plugs at least every 20,000 miles!

 

 

BTW if you still have your heart set on Irridiums get Denso's they are cheaper and make the plugs for HKS!

 

John they set the 11'B's to.92mm in the states if that is any guideline!

Originally posted by TopLess

 

2. The 11B that will deliver the spark at the right point in the chamber, giving greater BHP, fuel economy, cooler chamber temp, but there maybe a greater increase in the wear of the plug(alledgedly) but I think most people on here who run larger bhp would check their plugs at least every 20,000 miles!

 

 

 

 

 

 

 

Hey Mark!

 

I was talking to Latz on the phone today about your theory! I think he is still pissing himself laughing at the HKS plugs not delivering the spark in the correct place:D:D:D