I did a search and came back with 100+ results soooo...

I know there are three different types of plugs
Copper
Platinum
Iridium

I have heard of gaps from 0.8 to 1.1

Platinum and Iridium last longer but how much under normal driving?
I met a fellow member and he uses coppers every 10k.

Mine are Iridiums and they've lasted 100k.

I have learnt that the gap depends on the boost you are running, for stock the gap is 1.1mm if you are running 12psi or above 0.8 is recomended, as for plugs there is no perfomance gain to be gained from any but the life of the plug is greatly increased with platinum (80,000ks) and better still with iridium (100,000-160,000ks) compared to coppers which are recomended to change at 5,000ks although some say they last to 10,000 upto 40,000, if you can change them yourself go the coppers recomended below, I am using iridiums and they have been in there for 100,000k now and still good, I know because I keep pulling them out when something else stuffs up. Price wise they arent worth it really, I have been told that they are good in motors where changing the plugs are an absolute pain.


Generally speaking if a plug has a higher number than another it runs a colder heat range. eg. BCPR6ES ..... BCPR7ES colder plugs are good for preignition troubles.
Boost effects spark gap at 12 psi and above, the gap narrows down to 0.8.

FOR COPPER

They are good to 5k last at least 10k up to 40k

NGK for RB25det................. BKR6EYA or Platimum PFR5G-11
NGK for rb20/26det............. BCPR6ES or Platimum PFR6A-11
NGK for RB25NEOdet............ BCPR6ES or Platimum PFR6A-11

For PLATINUM

Good to 80k


NGK for RB25det................. PFR5G-11
NGK for rb20/26det............. PFR6A-11
NGK for RB25NEOdet............ PFR6A-11
NGKs Website


For IRIDIUM

Good to 150k

NKG for RB25det................ BKR5EIX-11
NKG for RB25neo............... BKR6EIX-11
NKG for RB20/26det........... BCPR6EIX-11
Denso for Rb25det............. IK20
Denso for Rb25det.. cold.... IK22

And go Here for a good SAU price on the Iridium plugs.
If you change your plugs and still have misfire isssues especially around the 3,000 - 5,000 rpm range it could be your coil packs are stuffed, its fairly common considering mine was 10 yrs old when mine started arcing out. Splitfire coilpacks are the best replacement and you can get a great deal from Dan (if he gives me a link)

Register on the forums for fewer ads.

NGK BKR6E -8

I think thats if off the top of my head, but they come gappd at .8 which is what i use. they are around $2 each and i change them when i change the oil every 5k

NGK coppers for rb20 (and i think rb25) are:
BCPR6ES

they are gapped at 0.8mm from the factory

cheers

ok...I just did the biggest lot of finding this week...

Normal plugs for a Skyline RB25det -

You want the BKR6EYA's.

If you want to go a colder heat range, and stay in Copper, and NGK, get the BKR7E's.

As for Denso, IK20's for Iridium (Same as NGK "6" heat range) or the IK22's for Iridium Denso plugs (same as NGk's "7" heat range)

Denso copper - K20R-U - (same as NGK's "6" heat range)
Denso copper - K22PR-U (same as NGK's "7" heat range)

Use this tool, its the best I have ever seen.

http://www.denso.com.au/sparkplug/xref


Good luck finding any of the denso's you are after though.

here's a few tips also -

1. If the plug has a "-11" on the end, its gapped to 1.1 mm. If it has nothing on the end like this, its 0.8mm - 0.9mm gap.

2. Some have longer necks than others so be careful.

3. If you're running high boost and are running into pre-ignition problems, try "7" heat range (colder plugs) or 22 heat range in denso.

Thanks for your replies

+1 for some really great info.

Well done guys I'm sure this will help out a lot of people.

Cheers B)

Updated iridium section

I'm hoping that when I get a complete listing that I can this stickyed in the app section.

Posted by WRXHOON in another thread

And this by MegaGTS4 Here

what happens if you put the plugs in too tight?

I didn't really know how tight to put them in so I tightened them up pretty tight. Don't want them working loose?

Worst case scenario would be that you could strip the thread which would mean removing the head and then using a helicoil I guess

anyone else run NGK B6ES?

I run NGK BCPR6ES in RB25's gaped at 0.8 mm.

cheers

I'm running the same as SK but in a 7, so BCPR7ES, gapped at .8, also rb25.

Im running iridium BKR7EIX gapped at 0.8mm

cant remember but they are iridum NKG and cost me about $120 for the set

If you tighten the plug tooo much they can be a real @#$%^& to get out.

The more feedback the better, just to confirm I am on the right track.