Plugs For Rb25det

[Dorigecko]

Hey dudes. Time to change plugs in my RB25DET, but have some questions before I go buy plugs.

Speaking in NGK p/n's, what is supposed to be used is a PFR5G-11. One thing i can see wrong with that: They're a very, very hot plug to run.

no expert, but with a turbocharged car wouldn't it be better to run a colder plug, like a 6 or 7?

and is there any real benefits from running the platinum plug? or even iridiums? IFR6G11 i can obtain. not popular but are easy enough to source. would that be better? or would like bpr6es-11 be alright?

if someone has an NGK catalogue handy, can you confirm that bpr6es-11 is correct projection length matched to pfr5g-11s please?

cheers for any help.

also, has anyone experimented with plugs and found what they think to be perfect match?

Engine is RB25DET series 1, standard turbo, 9psi through medium FMIC, standard intake manifold, isn't burning quite as much fuel as it should but may be due to just overfuelling on account of my... ehem... "race" cat. *decat cough cough* and manifold suchlike. fuel isn't issue though. it has just developed a very slight miss under 900rpm, sporadically coming and going.

[blind_elk]

If you are not making a significant amount of power above stock, then the recommended heat range plug should be used. And Nissan / NGK specify a heat range 5 for this engine. Increases in power require a 'colder' (6, 7) plug.

The main advantage of platinum and iridium plugs over normal coppers is they are a longer lasting plug, so you don't need to replace them so often.

And when it boils down to it, "a spark plug is a spark plug". As long as you have the appropriate heat range, all spark plugs should work the same - the fuel and air mixture can't tell the difference.

[Dorigecko]

i see.

no worries.

might go iridiums. same price as plats. i'll try standard plugs to choose between 5 and 6 heat range. car makes 250hp atw.

[mad082]

i wouldn't bother with either platinums or iridiums. not worth the extra money. what are they now, like $25 or $30 a plug? for a similar amount you can get a full set of coppers that will work just as well and last nearly as along. i had coppers in my 33 and pulled them out after 10,000kms of reasonably hard driving and they were still fine. when i got the car it had iridiums in it that were only about 25,000kms old and they were stuffed. and i know people who haven't gotten 15,000kms out of coppers without any issues.

my advice would be to save your money and go the coppers. i ran both BKR6ES and BCPR6ES in the 33. the BCP plug is 2.5mm taller (height from thread to top of plug where it goes into the coilpack) but the BKR still contacts the coil fine. the section that goes into the cylinder is the same though.

[GODZ1LLA]

I got recommended to get the bcpr6es=11 and get them down to0.8mm with feeler guages they seem fine to me and my car is a slightly modded tommy kaira r33...

And at $4.90 each they're great lol

[PM-R33]

Get the pre gapped ones. A gapped plug with a feeler gauge is never as good as a pre gapped one.

I always ran BKR6E's, 20psi and never a problem. Now switching over to BKR7E's due to a power increase for the next tune.

[Dorigecko]

I've gone PFR6G-11, to learn for myself how long plats will last. costly decision, but hey wtf. for 90 bucks a set, i'm cool with it. I pulled BCPR6ES's out of it, checked the gap and they were .9s, standard gap. 1.1 i'm happy with, as i've just discovered i've got splitfire coil packs. f**kYEAH! erm, so yeah I'm hoping my ignition system can support the gap. it's not missing at all, but the old plugs i pulled out showed signs of a slight detonation. hoping it's just due to worn plugs, so i'm gonna listen out for it, and might rip them out after 1000km see how they look.