Changed a set of PFR6B-11C for ZFR7F-11 today. ZFR are copper plugs, so probably change them every time I do the oil but for £2 each, who cares?

 

For comparison, both plugs are 11.5 mm from base of threads to the top of the metal 'shroud' around the insulator. ZFR are 2mm longer from top of shroud to top of firing electrode. Think length wise this puts them between PFR6B-11C and PFR6B-11B.

 

The plugs I took out had definately overheated (insulator v. white and no deposits at all, electrodes glazed) so it's probably worth going up to 7's.

 

Seems to be running OK on 0.8mm gap, but didn't go for a long run because I left the oil cap off!!!

Hello,

 

Ok I shall put all wind ups aside and try to give an objective view!

 

The HKS/Denso Plugs (same thing except HKS are more expensive) are more resistant to heat, but there is concern that produce the spark at the wrong point in the chamber, due to its shorter reach!

As you increase the boost there is obviously more need to place the spark in the middle of the chamber to create a more even combustion! Or the increased turbulences will mean that the start of the combustion in the chamber will be uneven, because the turbulence will move the combustion from the central point! Just like a windy day moves a bonfire about.

 

The PFR6B-11B was commisioned by Nissan USA for cars with increased boost and tuning, it has a longer reach which does place the combustion point centrally in the chamber but it is not as heat resistant as the Irridium plug!

 

Tuning is not perfection it is a question of compromises and balance, the HKS/denso plug was designed for Japanese 103 octane fuel with higher combustion temps and the 11b was designed for USA fuel with 95 octane. Whereas Optimax is 98.6 a middle ground!

 

Quite often it involves debating about shades of grey, and the only answer is to get two identical cars and put them on a rolling road!

 

And then if you change one of the tuning parameters you have to do the test all over again!

 

If you still can't choose I suggest a decision making course!

Firstly, don't base the arguement on cost - just because something is more expensive does not mean it is better!

 

Secondly, the only factor that is changing here is the electrode material - this only effects longevity of the plug.

 

The engine will NOT detonate if you use the wrong material. Detonation is the ONLY thing that will cause engine damage if the plug is in the wrong HEAT RANGE. Heat range is NOT affected by the electrode material. If your cylinder temps are reaching high enough to melt the copper tips - how long do you think your valves will last?

 

At the end of the day, a copper plug may well be safer as it will die under detonation, whereas an iridium one will keep the fire burning for long enough to destroy the engine...

 

CheerZ,

 

Andy

Originally posted by Paul C

copper electrode plugs are more prone to damage from high temperatures & detonation associated with turbo charged engines. the money you saved on the plugs will look very small indeed if you need an engine rebuild!!

 

id never fit anything other than platinum or iridium plugs. not woth the risk IMO.

 

-11 plugs are supposed to have a 1.1mm gap, so your probably down on power too if youve closed them up.

 

 

Well I am going with Paul and Latz on this;)

 

 

Paul a bloody good Merc mechanic.

 

 

Latz has proved he knows how to tune cars.

copper electrode plugs are more prone to damage from high temperatures & detonation associated with turbo charged engines. the money you saved on the plugs will look very small indeed if you need an engine rebuild!!

 

Ok can somebody PLEASE tell me how a copper plug can cause detonation? If I had detonation I'd far rather the plug got trashed than the valves/pistons. How does saving money on plugs wreck your engine????

i never said it would CAUSE detonation, i said it would be more prone to damage FROM detonation.

 

damaged plugs = poor combustion. not something that any of us want.

 

all IMHFO!! :rolleyes:

Thats exactly what I was saying Paul ;) No damage can come about from using copper plugs. If anything they are more likely to save your engine under detonation...

 

CheerZ,

 

Andy

Pleased we're all agreed then:D

 

Seriously though, when I've used these for a while I'll post on what I've found.

 

MAC, do you have the measurements of the HKS plugs? I know the DENSO's are much shorter, but not sure about the HKS ones. Also, do you know if HKS 7 heat range is the same as NGK 7 heat range?

Originally posted by John Dixon

MAC, do you have the measurements of the HKS plugs? I know the DENSO's are much shorter, but not sure about the HKS ones. Also, do you know if HKS 7 heat range is the same as NGK 7 heat range?

 

 

John save yourself some money the HKS are the Denso plugs rebranded!

just had a chat with Duffer & he agrees the're crap!! LOL! :D

Originally posted by John Dixon

Pleased we're all agreed then:D

 

Seriously though, when I've used these for a while I'll post on what I've found.

 

MAC, do you have the measurements of the HKS plugs? I know the DENSO's are much shorter, but not sure about the HKS ones. Also, do you know if HKS 7 heat range is the same as NGK 7 heat range?

 

 

Ok John it's like this;)

 

 

 

 

 

We measured the stock plat plug against the HKS one,It was no more than 1.5mm shorter yes 1.5mm .

 

The reason for this is to get rid of the heat created by a higher level of boost from the combustion chamber via the cylinder head. the shorter the plug the better it is at doing this.

 

As far as comparing the heat range 7 NGK from a heat range 7 HKS not sure.

Mac, when you say stock plug do you mean PFR6B-11C?

I might get a set if the coppers don't last long, but at the minute while I'm playing with the maps I'll stick with the coppers for safety.

Cheers

Originally posted by John Dixon

Mac, when you say stock plug do you mean PFR6B-11C?

I might get a set if the coppers don't last long, but at the minute while I'm playing with the maps I'll stick with the coppers for safety.

Cheers

 

Yes those are the ones;)