Spark Plugs

[Shazza24]

Hi ppl,

So i got new spark plugs going in tomorrow for the 33 gts-t (NGK PFR5G-11). However car is modified by 50 or so horses. Do i go colder? (NGK PFR6G-11)

Cheers,

Shazza

[Kinks]

5 is quite a hot plug for australian conditions, it is the original spec heat range but most people here run a 6 plug (slightly colder).

if you're not experiencing any pinging then the 5's are OK, but if you get knock then a colder plug might help.

also, no real need to bother with iridiums or platinums just use coppers and change them more often. at the very least you look at your plugs more often and you'll know if one cylinder is leaning out or detonating by damage to the plug (if you can't hear it).

[Galois]

i'd go a bit colder for even a stock gtt or gtst in aussie conditions so with more power def go the 6's, better safe then sorry right?

[mad082]

personally i'd go the 6's, but i wouldn't be using platinum plugs, i'd just go with copper. BCPR6ES is the part number for the ngk copper plugs i was running.

[Galois]

there are also those cheap bosch platinums, $38 for 6. almost as cheap as ngk coppers

[Shazza24]

Thanks guys, think I will take you advice and change the plugs to a 6. Probably keep the platinum's though as i will be checking them every 5-10 thousand Km's!

Cheers,

Shannon

[mad082]

if you are going to be checking them that often you might as well go the coppers. you will generally get 10,000 to 15,000 out of them.

[Kinks]

^^ yep go the coppers you will get just about as much life out of them. always prefer to replace plugs a bit more often the working bits of platinums and iridiums are probably OK but after 40,000km even platinums look like shit.

platinums and iridiums are for shit cars liks alfas where you have to remove the engine to get to the plugs. ours just have a crossover pipe and some coil packs, don't be a sissy service the plugs more often and just use coppers!

I believe the correct plug is BKR6ES-11 but BCPR6ES-11 is identical except the external snout is a very tiny bit longer, which makes no difference in practice so either plug will work. the -11 means 1.1mm gap which is fine unless you're running high boost or your coil packs are shot. If you can use 1.1mm gap rather than BKR6ES (no -11 means 0.8mm gap) then your spark will be bigger which helps combustion.

[Galois]

^ all true and exactly what im doing

except from like 5 posts up:

there are also those cheap bosch platinums, $38 for 6. almost as cheap as ngk coppers

[mad082]

^^ yep go the coppers you will get just about as much life out of them. always prefer to replace plugs a bit more often the working bits of platinums and iridiums are probably OK but after 40,000km even platinums look like shit.

platinums and iridiums are for shit cars liks alfas where you have to remove the engine to get to the plugs. ours just have a crossover pipe and some coil packs, don't be a sissy service the plugs more often and just use coppers!

I believe the correct plug is BKR6ES-11 but BCPR6ES-11 is identical except the external snout is a very tiny bit longer, which makes no difference in practice so either plug will work. the -11 means 1.1mm gap which is fine unless you're running high boost or your coil packs are shot. If you can use 1.1mm gap rather than BKR6ES (no -11 means 0.8mm gap) then your spark will be bigger which helps combustion.

my theory is that the extra 2 or 3mm taller that the BCPR6ES plug is will mean that it makes better contact with the coil, but it really is SFA difference. i ran both the BCP and BKR plugs in my 33 and they both worked fine

[Shazza24]

So i put in the NGK PFR6G-11 was going to re-gap them to factory specs (1.05mm) but thought f*** that! Old plugs were covered in a reddish hue on the insulator?(NGK BKR5EIX-11P) Also fixed a slight idle problem i had, overall happy and changing fuel filter in next couple of days! Thanks for the input!

Cheers,

Shannon