Jump to content
SAU Community

Importance Of Changing Spark Plugs


Recommended Posts

My r33gtst is running 18psi and 247rwkw.

I have been using BKR6E plugs and just started getting misfire above 4000rpm.

The plugs have only been in about 12,000km. However, I have had a dyno tune and 1/2 a track day on those plugs. The plugs still looked ok.

The misfire is now completely gone and the response is back in my car. Heaps more power.

Replaced with the same NGK BKR6E.

I suggest changing every 5-7,000km.

Anybody know how long the iridiums last before a loss in power?

It's not the most fun job changing them but only takes me about 1-1.5 hours now..

If running less than 14psi you probably wouldn't get the misfire as quick but you are probably losing power by not chaning your plugs.

Edited by benl1981
Link to comment
Share on other sites

  • Replies 43
  • Created
  • Last Reply

Top Posters In This Topic

Coppers have never really lasted longer than 10,000kms, and should be changed every 10,000 or sooner, just do them everytime you change the oil.

1.5hrs to change plugs is a bit of time though, i could do it faster on my 25 and i dont set a blistering pace... and the 26 is faster again for obvious reasons.

Iridi's generally dont last as long as they say unless in a stock car.

But with tuned cars, more boost, higher temps and everything else associated etc etc, the reality is they dont last anywhere near that.

So stick to coppers, change them at least every 10thou and live happily ever after, its pretty much a given, surprised you didnt realise that :)

Link to comment
Share on other sites

the way i see it is that the coppers should be changed atleast every 10k, the iridiums say every 100k, lest just say that the iridiums only last 70k, the coppers are what, $2-$3 each, lets say $2.50, iridiums are about $15 each, so each change is costing you $15 for copper and $90 for iridiums, but you have to change the coppers 7 more times than iridium so really it cost $105 in coppers and a lot more time spent changing then, even lets say that you only get 60k out of iridiums the money breaks even but your saving a lot of time, even if you only get 50k they only cost $15 more and still save you a lot of time.

i know what i would prefer to be doing, and its not changing plugs all the time.

And this equation is assuming you do the coppers at 10k, which would probably be strecthing the life of them, where as 50k is not stretching the life of an iridium.

Edited by W0rp3D
Link to comment
Share on other sites

They would have needed changing after the dyno tune.

Platinum and Iridium plugs do last longer under normal driving conditions compared to copper but they all pretty much degrade as quick as eachother when put through heavy work on a dyno or on the track.

Depending on how often you go on the track the best bet is putting a new set of coppers in and let them cop the abuse of the track day, throw them out after and have a dedicated set of street plugs so that you can be confident you're not losing performance to over worked plugs on the street.

Link to comment
Share on other sites

the way i see it is that the coppers should be changed atleast every 10k, the iridiums say every 100k, lest just say that the iridiums only last 70k, the coppers are what, $2-$3 each, lets say $2.50, iridiums are about $15 each, so each change is costing you $15 for copper and $90 for iridiums, but you have to change the coppers 7 more times than iridium so really it cost $105 in coppers and a lot more time spent changing then, even lets say that you only get 60k out of iridiums the money breaks even but your saving a lot of time, even if you only get 50k they only cost $15 more and still save you a lot of time.

i know what i would prefer to be doing, and its not changing plugs all the time.

And this equation is assuming you do the coppers at 10k, which would probably be strecthing the life of them, where as 50k is not stretching the life of an iridium.

Irdi's wont last 50k, let along 100k in a well modified car, thats the problem.

Coppers take a beating for thier life whilst the iridi's will foul much easier. Do 10 cold starts with short drive in a row (ie, trip to the shops and back) and you can foul em that easily.

Say a fuel reg dies, in 50k, easily could happen, iridi's dead.

Fuel pump gets a bit tired, again, iridi's dead

So many things to destroy them, when what does it matter if your only using $15 worth of plugs :)

Soon as you kill one set prematurely of iridi's you've lost the money on them right then and there.

I killed a set after 20k (a few years ago now), never gonna do it again @ nearly $100 a set. Not worth it for a modified car.

Stocker = yeah probably much more viable and id go that route if it was.

Link to comment
Share on other sites

Irdi's wont last 50k, let along 100k in a well modified car, thats the problem.

Coppers take a beating for thier life whilst the iridi's will foul much easier. Do 10 cold starts with short drive in a row (ie, trip to the shops and back) and you can foul em that easily.

Say a fuel reg dies, in 50k, easily could happen, iridi's dead.

Fuel pump gets a bit tired, again, iridi's dead

So many things to destroy them, when what does it matter if your only using $15 worth of plugs :)

Soon as you kill one set prematurely of iridi's you've lost the money on them right then and there.

I killed a set after 20k (a few years ago now), never gonna do it again @ nearly $100 a set. Not worth it for a modified car.

Stocker = yeah probably much more viable and id go that route if it was.

lol ur worrying about $100.

never had an issue with mine and been using for some time.

I have checked them every 5k and so far no issues with the iridi's at all after 10k.

Personally for $100 every 10k or whatever I couldnt give a toss. Although now you can get them online much cheaper now

Link to comment
Share on other sites

I guess i've never noticed - running only 10psi before I think I got about 20k between changes, without even getting a miss.

Probably about 1-1.25h is realistic . But I doubt you'd get much quicker than that when you have to take off strut brace, intake pipe etc and then reinstall. I reckon a workshop would get you for a good 1.5-2 hours..

PS. BKR6E come gapped to 0.8mm. I checked them last time and all good. This time I didn't bother.

Edited by benl1981
Link to comment
Share on other sites

1+ hours to change plugs??? wtf are you guys on?

takes me 20 mins max, and yes i have a coil pack cover on, still with cross over pipe etc.

I run coppers, NEVER had a prob with them much prefer paying SFA for a plug rather then 120+ for 6 of them...

Link to comment
Share on other sites

ok quick noob question... sorry to hijack thread..

but my r33gtst misfires like crazy aftrer 5000RPM.

I changed mine about 5000ks ago (the iridium ones) but it still does it...

how do i gap them to 0.8?

can it be the coil packs? its driving me crazy... just saps the power...

Edited by usmair
Link to comment
Share on other sites

1+ hours to change plugs??? wtf are you guys on?

takes me 20 mins max, and yes i have a coil pack cover on, still with cross over pipe etc.

I run coppers, NEVER had a prob with them much prefer paying SFA for a plug rather then 120+ for 6 of them...

20min if you having a beer at the same time... LOL

Link to comment
Share on other sites

Buy plugs that are 0.8 rather than regapping 1.1's (most 0.8's are the same plug number with a -8 at the end). Many misfire problems are caused by aged coils, spend $500 on a set of splitfires and you will be amazed at the difference.

On a side note, when I changed the plugs in my Toyota Hiace at 100,000km the guy tried to sell me Iridiums as they are the factory plug that Toyota uses due to the difficult location on the engine. I handed them back and bought a set of coppers and ran them for an entire 100,000km without any issues at all. I've now run a second set of coppers for 103,000km without any problems :)

Link to comment
Share on other sites

I guess i've never noticed - running only 10psi before I think I got about 20k between changes, without even getting a miss.

Probably about 1-1.25h is realistic . But I doubt you'd get much quicker than that when you have to take off strut brace, intake pipe etc and then reinstall. I reckon a workshop would get you for a good 1.5-2 hours..

PS. BKR6E come gapped to 0.8mm. I checked them last time and all good. This time I didn't bother.

You're telling me you can't change your plugs with the strut brace on? Do you even KNOW how to use a socket set properly?

I've done mine before with the intake pipe still on there also. (Yes, straight over the motor pipe!) they're piss easy, and DO NOT take 1 - 1.5 hours to do!

Link to comment
Share on other sites

I find it takes more time to work around things than take them off in most cases. I forgot I had to look for missing tools so maybe closer to 40mins but I have a look down each spark plug hole with torch and guess took my time a bit.

You guys must be pros :0

Link to comment
Share on other sites

do it enough times and you'll be a pro also....

i had my car dyno'ed a while ago and had missfire issues... by the time we sorted it out i had the plugs out and back in 3 times in that single day. seriously its not that hard once you have the right tools in front of you.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share




  • Similar Content

  • Latest Posts

    • Well, yeah, the RB26 is definitely that far off the mark. From a pure technology point of view it is closer to the engines of the 60s than it is to the engines of the last 10 years. There is absolutely nothing special about an RB26 that wasn't present in engines going all the way back to the 60s, except probably the four valve head. The bottom end is just bog standard Japanese stuff. The head is nothing special. Celicas in the 70s were the same thing, in 4cyl 2 valve form. The ITBs are nothing special when you consider that the same Celicas had twin Solexes on them, and so had throttle plates in the exact same place. There's no variable valve timing, no variable inlet manifold, which even other RBs had either before the 26 came out or shortly afterward. The ECU is pretty rude and crude. The only things it has going for it are that the physical structure was pretty bloody tough for a mass produced engine, the twin-turbos and ITBs made for a bit of uniqueness against the competition (and even Toyota were ahead on the twin turbs thing, weren't they?) and the electronic controls and measuring devices (ie, AFMs, CAS, etc) were good enough to make it run well. Oh, and it sounds better than almost anything else, ever. The VR38 is absolutely halfway between the RB generation and the current generation, so it definitely has a massive increase in the sophistication of the electronics, allowing for a lot more dynamic optimisation of mapping. Then there's things like metal treatments and other coatings on things, adoption of variable cam stuff, and a bunch of other little improvements that mean it has to be a better thing than the RB26. But I otherwise agree with you that it is approximately the same thing as a 26. But, skip forward another 10 years from that engine and then the things that I mentioned in previous post come out to play. High compression, massively sophisticated computers, direct injection, clever measuring sensors, etc etc. They are the real difference between trying to make big power with a 26 and trying to make big power with a S/B50/54 (or whatever the preferred BMW engine of the week is).
    • Is the RB26 actually that far off the mark? Honestly from where I'm sitting a VR38DETT is not actually that much more advanced than the RB26. Yes, there is a scavenge pump on the VR38, it's smarter in a number of ways but it's not actually jumping out to me as alien technology. Something like a B58 or V35A-FTS on the other hand has so many surprising little design features that add up to be something that just isn't comparable. 
    • https://www.carsales.com.au/cars/details/2021-nissan-skyline-400r-auto-rv37/SSE-AD-17857548/ Well there you go 
    • Chris won't reply. He doesn't visit the forum much anymore. You can try these guys https://www.facebook.com/autotainment/ They did mine many years ago
×
×
  • Create New...