Spark plug choices by NGK?

[rayaapp2]

NGK lists two plugs for my RB25. I went on their website and typed up 94 skyline RB25DET and they came up with 2 stock replacements. I know there are alot of threads about which plug to run, but I cant find a direct answer about what to run. Most of the threads are about hot or cold plugs.

 

PFR6G-11 is what is in my engine currently and appears to be original

PFR6B-11B is recommended by a lot of posts for stock replacement

PFR5B-11 is also recommended by a lot of posts for more Boost "colder plug"

PFR5G-11 is NGK's website's listing for OE replacement

BKR5EIX-11 is also NGK's Website's listing for OE replacement "IRIDIUM"

 

 

All I want is a stock replacement to be honest. I was going to just get the PFR6G-11 as that is what is in there, but who is to say that is correct.

So I checked the NGK website and saw the 2 listings. Now that I have far to many choices than there should ever be. I dont need colder plugs as I am running the RB stock. So can someone convince me why I need to run a particular plug? Then there is the question of Lazer Platinum VS Iridium.

 

here is one of the more interesting threads I ran across about the subject but unfortunately its is for the VG30DETT not RB!

http://www.zcar.com/forums/read/3/1170880

[cheftrd]

NGK plugs for the RB25DET are:

 

Nissan part# 22401-1P116

NGK part# PFR6G-11

P=Platinum

F=14mmD x 19mmL threads and 16mm socket

R=Resistor

6=Heat Range

G=Length of the plug from tip to seat (50.5mm), center electrode protrusion (3.5mm), chamber protrusion (0mm).

-11=1.1mm gap

 

Running more boost, larger turbo, etc., step up to a 7 or 8.

 

NGK Iridium IX # BKR6IX-11

NGK Iridium Max # BKR6EIX-11

NGK Iridium "tuned engine" plug # IRIWAY (7,8,9,10,11)

NGK Racing # R7434 (8,9,10) (about $35 each)

NGK Low Budget # BCPR6ES-11

 

Plugs get hotter as the # drops. 5 is hotter than 6. PFR5G-11 is listed as RB25DE and RB25DET plug for R33 and PFR6G-11 is a little colder and the RB25DET plug for the RB34. The Nissan # is the same for both engines

 

The B-11B plug electrode protrudes 6.5mm (3.5mm stock) and the plug protrusion is 3.5mm (0mm stock), making it way hotter than the stock plug. There is no PFR#B-11 plug listed.

[RB26powered74zcar]

I've seen these advertised on the RB forums;

 

#2667 BKR7EIX

#2668 BKR8EIX

 

 

NGK Racing plug #4899 R7436-9 $41.52ea.

6@ $249.12

 

BCPR8ES as a common street plug with 0.7 to 0.8 gap.

[rayaapp2]

Maybe a few posts I was looking at were getting the "G" and the "B" mixed up. I didnt find an actual listing for the "B" plugs either. Were did you get that info? I was looking on the NGK website and all I could find was the info on the left side of the page and it was incomplete.

 

It looks like this:

Extra Long Life Double Platinum Plug,

14mm Thread, 19mm (3/4") Reach,

5/8" (16mm) Hex Size, Gasket Seat,

Resistor, Extended Metal Shell,

Solid Terminal, Extended Projected Tip,

Fine Point Platinum Center Electrode

and Platinum Tip Laser Welded on

Ground Electrode, .044" (1.1mm) Gap

 

I guess it doesnt matter that much.

I just went onto NGK's website again...

R33 lists "5"

http://www.ngk.com/results_appNonUS.asp?internationalMotiveID=3553

R34 lists "6"

http://www.ngk.com/results_appNonUS.asp?internationalMotiveID=3557

 

No listings for the R32 in Turbo trim though.

 

Anyone have any comments to compare the platinum VS the iridium

[cheftrd]

I have the NGK and NGK Racing catalogs.

 

The R7436 plug has a 2.5mm longer insulator, and will still work. They have the same type "C" fine-wire ground electrode. Race plugs should only be used in race engines, though. If it does a lot of idling or street driving, they'll carbon foul pretty quick

 

R32 turbo and non turbo RB20 use PFR6A-11 and PFR5A-11 respectively. The "A" plug is 2.5mm taller at the electrode. R32 RB25DE uses the PFR5K-11, which is pretty much the same thing as the "A" plug. One's a JIS standard and the other's ISO.

 

Iridium melts at a much higher temperature, so it has a smaller center electrode, allowing the spark to initiate at thousands of volts less. Where the platinum plug "blows out", the iridium will continue to fire. Basically, iridium can make more power than the platinum plug before it hits the ignition-misfire wall. Iridium is also much harder than platinum, so the wear resistance is better.

[rayaapp2]

See and this is were I get lost.

 

I refuse to skimp on spark plugs. Everyone so far says Iridium is a step up and stands up as a more robust performance plug than the double platinum. Then there is the fact that the listed Iridium plugs are half the price of the double platinum plugs. Why would you run the double platinum plugs if you could get a superior plug for half the price? Im just having a hard time convincing myself to buy the Iridiums over the double platinums. I cannot confirm it but I suspect that the Iridium plug has Iridium on the center electrode but not the ground side like the double platinum. That may be why they are less expensive. If that is the case then the Iridium is pointless as the ground side will wear faster than the platinum tip version.

[cheftrd]

My info on the platinum vs. iridium "debate" comes straight from Nippon Denso, not an Internet forum.

 

NGK and Denso race plugs are iridium. The stock replacement Denso iridium plugs center electrode was designed to last 200,000 miles.

 

Platinum center electrodes are about 1.1mm in diameter. Iridium center electrodes are about 0.7mm. Iridium race center electrodes are about 0.4mm.

 

In well tuned, semi-daily driven 250hp per liter engines, NGK Racing Iridium fine-wire plugs (with the smallest electrodes) last me three years.

 

In an 800hp RB26, plugs will die from cracking, fouling, etc., cams will wear out, piston rings will wear out, bearings will wear out, etc., long before the plug electrodes wear out from erosion...

 

The "which one lasts longest" debate is senseless. Guys arguing on Internet forums about which 60,000+ mile plug will last longest when they're putting them in high performance engines that probably won't see that much millage in its lifetime ...

[rayaapp2]

There is a very good chance I will be seeing over 60K miles in the next 2 years. I plan on driving the car daily. The car isnt a track car, its my DD. The RB being the reliable power plant that it is in stock form and being the logical step up from the L was why I chose it to put in my car. That way I could get the reliable, but also could get the fun factor in there. After messing around with the L28et and trying to get it to survive the boost to get what I wanted out of it the car turned into a project so the RB was the chance to make it a driver again.

 

So I guess what Im trying to walk away from this with is a little more knowledge to try and make a good choice for my stock RB. If both plugs last about 60K miles and the Iridium will out perform the platinum that sounds like the way to go. I shouldnt have to worry about fouling out as the ECU default is lean except after a hard run when they try and burn the fuel in the cat.

 

**********************************************************************

 

So I went ahead and ordered the Platinum PFR6G-11 plugs for the car just because they are what the engine is designed to use. I couldnt come up with a good enough reason to use the Iridium plugs in my stock application.

 

On a side note I was warned that there is a chance with either plug but it is even more so with the Iridium that the tip will melt off the electrode and fall into the combustion chamber. The Iridium can do major damage to everything from pistons to valves as it is very hard and gets very hot. This info was directed towards a much higher performance engine other than my stock RB. I guess the Iridium gets so hot it dis-lodges itself from its seat and falls into the combustion chamber. But if you were running a race motor or high performance motor I would think as it was stated earlier in this thread you would be taring the engine down long before such a failure occurred. Second hand info though so take it with a grain of salt and find out for yourself.