Spark Plugs

[Hanaldo]

Hey all,

I spent a good couple of days last week reading all the threads in the FI section and the general maintenance section to make sure I bought the right spark plugs for my car, and I ended up going with NGK Iridium BKR7EIX which are gapped to 0.8mm from factory; only put them in my car on Friday.

But my car is now with Andrew at Hyperdrive waiting to go on the dyno and he called me up to ask what plugs I have. When I told him, he said they are definitely going to have to come out, the plugs need to be gapped to a maximum of 0.7mm but ideally 0.65mm. So it appears I have wasted a hell of a lot of money as the Iridiums can not be regapped and now Andrew thinks he will needs to waste dyno time seeing if they will misfire, then waste time removing the plugs and replacing them, etc.

But wherever I look on SAU, everyone recommends using 0.8mm gaps for boost over 12psi. I'm not sure what boost he is intending to run, I know the turbo I'm using has a 20psi atmospherical actuator so low boost will probably be around 15-18psi. I had been expecting the car to make between 350-380rwhp on high boost. Are his fears correct and I've made a mistake choosing those plugs, or am I getting in a panic over nothing?

Cheers,

Martin.

[SKYRYAN]

I went to the drags last week and was miss-firing down the strip, that was about 1.3 bar and the plugs are ~7,000kms old. It got worse as the night progressed Still, I managed at 13.036.

I think next plug change I'll be looking to re-gap below 0.8mm, but I just use copper plugs. Why can't you re-gap iridiums?

[Hanaldo]

I was told you shouldn't do it with Iridiums, they can't handle it or something?

[GTS-t VSPEC]

Iridiums are a waste of money. Cheap copper BCP6ES plugs are fine, they come pre-gapped to 0.8mm, and you can gap them down as you increase boost. If you're planning on running 20+psi, then I use the BCP7ES, which are a cooler heat range.

[ZXY]

only problem with coppers are changing spark plugs takes ages on a rb25 if you the plenum that croses over

Edited November 24, 2010 by ZXY

[GTS-t VSPEC]

only problem with coppers are changing spark plugs takes ages on a rb25 if you the plenum that croses over

20mins once you've done it a couple times, although the R34's are much worse with there damn throttle control butterfly

[Hanaldo]

Yeh and KYP have put all sorts of sensors on the valley cover that need to be unplugged and removed. Took me about 3 hours to do it on Friday, but it was the first time I've done it on a Skyline. Could probs do it quicker next time.

I just got Iridiums because I figured it's better to spend $85 once every 60000kms than however much coppers cost every 5000kms.

[StealthX]

Bro, if your actuator has a spring pressure of 20psi you wont be able to run under that boost pressure...

[JonnoHR31]

i have a brand new set of the copper plugs you need sitting here if you need them asap

gap depends on a few things, mainly boost and condition of your coilpacks. but unless you have some really good coilpacks you'll need a smaller gap than .8 for 15+psi

[lunjiaow]

When i used splitfire coilpacks i was running .8mm or maybe a bigger gap and no misfires with 18psi.

I always replaced my sparkplugs every 5000kms with copper ones.

If you are running original coilpacks, i would gap a set of copper plugs down to .6mm to stop the misfire problems on high boost.

Otherwise get a set of aftermarket coilpacks and stick to the iridiums since you have trouble taking out the sparkplugs.

[snozzle]

coppers all the way man, do not bother with iridiums - you should have picked up on that if you did read all the threads

change them every 2nd or 3rd oil change

[Hanaldo]

Bro, if your actuator has a spring pressure of 20psi you wont be able to run under that boost pressure...

Yeh 20psi atmospherical, so at the manifold will be 15-18psi. What I've been told anyway... My boost gauge reads 16psi with the boost controller switched off, so I guess that's correct.

coppers all the way man, do not bother with iridiums - you should have picked up on that if you did read all the threads

change them every 2nd or 3rd oil change

I know, everyone vouches for coppers but I went for Iridiums because I didn't want to be changing plugs every 5000kms lol. I will probably go with coppers next time.

Anyway, car doesn't have any issues as far as I know... I have Splitfire coilpacks. It does have a slightly rough idle like it's misfiring at idle but I thought that is more likely from the 650cc injectors not the spark plugs???

[snozzle]

5000kms is far too early for coppers!

ive done 12,000km on mine (bcpr7es), still like new and never mis fired - I run a heat range 7 though as i dont waant any chance of pre-ignition although a 6 would be better for a daily driven car but eh, better safe than sorry

ill change mine at 15,000km even though i know they will go more, just good to keep it routine instead of waiting for a failure

Edited November 24, 2010 by snozzle

[gt35slider]

Use NGK copper BCPR7ES and gap to .8 and will be sweet

[SKYRYAN]

Use NGK copper BCPR7ES and gap to .8 and will be sweet

Try for the ones without the R if you can though. From memory, the R is a resistor type or something and has a slightly weaker spark... but it's there to reduce electronic knocking/pulses? I should google it- no wait, you google it for a better answer.

[Dani Boi]

5000kms is far too early for coppers!

ive done 12,000km on mine (bcpr7es), still like new and never mis fired - I run a heat range 7 though as i dont waant any chance of pre-ignition although a 6 would be better for a daily driven car but eh, better safe than sorry

ill change mine at 15,000km even though i know they will go more, just good to keep it routine instead of waiting for a failure

This. Dont know why everyone does it at 5,000km. When I pull them out after 10,000km they still look fine.

[SKYRYAN]

This. Dont know why everyone does it at 5,000km. When I pull them out after 10,000km they still look fine.

Probably depends on your tune/mods and how you drive as well I guess. You're a pussy driver and have no fast and furious mods, so yours last longer

[Dani Boi]

Probably depends on your tune/mods and how you drive as well I guess. You're a pussy driver and have no fast and furious mods, so yours last longer

You're probably right though.

[br3ndan]

I am using irridium plugs and have been for the past year or so. No problem what so ever with them. on low or high boost and they are gapped at 0.8... and I am still using standard coilpacks at the moment as they are still going strong.

I used them for the same reason as Hanaldo... I didnt want to unplug / unscrew everything every 5k or so...

[gt35slider]

The trionic system uses the resistor ® type spark plug to read combustion chamber conditions and "inform" the ECU about boost and ignition advance requirements for the engine in real time and continuously. This is why you must use resistor type plugs