Possible Knock

[Hanaldo]

Just as it is sort of on topic, can anyone in here tell me the code for the copper plugs I would need? I just spent 40 minutes shaking my head at all the misinformation in the spark plug threads in the General Maintenance section, just want a straight answer from someone who is using copper plugs at a similar power level to me (lets go with 400rwhp; it's debatable at the moment but I'd rather get plugs for that heat range than a lower one).

I also gave NGK a call but they were trying to convince me to get Iridiums again. Damn bloke wouldn't give me the code for coppers

[SargeRX8]

BCPR7ES, they are gapped at .8 The 11 variation is a 1.1mm gap. The BKR7ES V groove is a better option if you can find it. Same plug just the ground at the end of the plug is V grooved.

[LANDSCRIBBLE]

Bcpr7es $4.30 ea. bkr7es v groove $4.30 ea. quoted from veales.

[Hanaldo]

Thanks guys. Is the 7 a good heat range? My current plugs are either a 6 or a 7. Not knowing for sure doesn't help much

[SargeRX8]

I get the standard plugs for $3.50 a piece but the chap I get my shit from doesn't stock the V groove plugs.

Stick to 7. All my skylines have ran 7's with no issues. None of my skylines are stock. People HAVE had issues using 6 plugs. You don't use 6, you use 7.7 isn't good, its the best.

Edited December 12, 2011 by SargeRX8

[Hanaldo]

Done and done, thanks mate I'll head to my local Veales/Repco to see if they stock the v-grooves.

Edited December 12, 2011 by Hanaldo

[SargeRX8]

Find out how much they are at repco and let me know. I cbf calling them because they are shit and cbf driving there because its out of the way from everywhere. Supercheap are horrible, they stock jack f**k all and everything I have EVER needed for my car(bar oil) is "special order".

[GTRNUR]

I do wonder if some of you guy's just love working on your cars for the hell of it. I hate pulling plugs and get paranoid about scratching the paintwork on the engine when I have to.

There is nothing wrong with using iridium plugs in a modified engine provided you tune the car for it accordingly. You will be able to get a better economy tune with Iridiums as well, because they will survive higher combustion temperatures much longer than a copper plug. Im using BKR6EIX re-gapped to 0.8mm, standard coil packs, and run 1.75 kg/cm boost with easily over 500hp atw and the engine never miss-fires. About 18,000k's on the engine now too and have only pulled the plugs to compression test it.

You can't keep your AFR's extremely rich (10.5-11) with the iridiums though, as they will carbon up faster than a copper plug due to there being less plug surface area. I feel the most common reason people (or some tuners) go for a copper plug is that they allow that super rich or "safe" tune to still run once you have drowned the plugs in fuel. Really, copper plugs are the "old school" approach of allowing a rough/rich tune to still run.

But if you tune it to run 12:1 at full load and richen up to 11.8 - 11.7 past 6500-7000 rpm and you will make better power and be able to run the iridium plugs. The richer AFR's past 7000 keep your EGT's safe where they need to be while you will get better power and torque from down low through mid range RPM's.

You can also easily run 15.5:1 at 100km/h cruise speeds on an RB25 and crank in the ignition to achieve great fuel economy. Im running 16 - 16.2:1 cruise AFR's (@ 100km/h) with my stroker motor and still have safe EGT's. The leaner cruise combustion temps will burn off any carbon build up from when you are hard on boost. Try that with a copper plug and they just don't survive the sustained 800 degree plus combustion temps.

[MrStabby]

I do wonder if some of you guy's just love working on your cars for the hell of it. I hate pulling plugs and get paranoid about scratching the paintwork on the engine when I have to.

There is nothing wrong with using iridium plugs in a modified engine provided you tune the car for it accordingly. You will be able to get a better economy tune with Iridiums as well, because they will survive higher combustion temperatures much longer than a copper plug. Im using BKR6EIX re-gapped to 0.8mm, standard coil packs, and run 1.75 kg/cm boost with easily over 500hp atw and the engine never miss-fires. About 18,000k's on the engine now too and have only pulled the plugs to compression test it.

I have a CRD tune with iridiums. They're about 30,000kms old and still going strong.

[Harey]

Sounds like maybe just pull em out and check out the condition of the plugs.

[Rolls]

Get some knock ears on it and confirm if it is knock, don't drive WOT until you do this. I'm serious, not WOT!

Don't drive your car til you get your tuned fixed, you have been warned.......

Just joking. Just goes to show it happens to all the people who have got perfectly tuned cars too.

No one said it doesn't, but it ALWAYS happens to people who don't have properly tuned cars lol.

Edited December 13, 2011 by Rolls

[lilcrash]

Get some knock ears on it and confirm if it is knock, don't drive WOT until you do this. I'm serious, not WOT!

No one said it doesn't, but it ALWAYS happens to people who don't have properly tuned cars lol.

i get the impresson you think im an asshole. my response was only a joke, im fairly sure hanaldo knows whats going on.

Edited December 13, 2011 by lilcrash

[SargeRX8]

You say you are popping around on idle, and its gurgling/surging.... These symptoms are what my car was doing before the fuel pump failed. You can't give a car stick on a failing fuel pump as it could run a lean condition and detonate. Then again, the detonation sound by the way you explained it still doesn't sound like detonation to me. Lean popping is nothing really, unless you are running low 13's to 12's afr you will lean pop on idle. All the other symptoms CAN be normal, between gears you can get a gurgle/pop as revs drop to idle. Light, microscopic amounts of throttle can cause the gurgling. I don't know, I just don't think you will hear the engine ping with a screamer and that is exactly what the sound is like, PING.

I was giving my car good stick on high boost after about 2 weeks of nothing. As soon as boost came on I heard a massive f**k off pop from my exhaust with a f**kLOAD of smoke, Power FC read 100 knock but the thing is my coil packs failed in that EXACT moment. Its an iffy situation. I'm not going to tell you its not knock and go WOT until something goes wrong but what I would do is change the plugs and give it a couple of runs and see how she goes. If symptoms persist, see a doctor. You can use a cheap method to hear detonation. Get some 4 - 6mm ID rubber tubing, vacuum hose, and get like a small screw, bolt or something you can screw somewhere into the block or in the head of the motor. Stick the other end in your ear hole and put a tissue in your other ear so you can only hear the noise in the tube. This acts like a doctors stethoscope, you will hear knock not as a PING but more a piston slapping a bore which will sound like a thud in your ear. The ping frequency is very high from the outside but the actual sound is around 4900Hz I think.

When Jez was tuning my car, he could hear knock every single time the power FC heard it by placing is head over the engine area and to me looked like he was blocking his ears to isolate the noisy sounds but let the lower frequency noises such as knock be audible. He would then hand signal the dyno man to back off the throttle if he heard knock even though he didn't haha.

[Hanaldo]

You say you are popping around on idle, and its gurgling/surging.... These symptoms are what my car was doing before the fuel pump failed. You can't give a car stick on a failing fuel pump as it could run a lean condition and detonate. Then again, the detonation sound by the way you explained it still doesn't sound like detonation to me. Lean popping is nothing really, unless you are running low 13's to 12's afr you will lean pop on idle. All the other symptoms CAN be normal, between gears you can get a gurgle/pop as revs drop to idle. Light, microscopic amounts of throttle can cause the gurgling. I don't know, I just don't think you will hear the engine ping with a screamer and that is exactly what the sound is like, PING.

I was giving my car good stick on high boost after about 2 weeks of nothing. As soon as boost came on I heard a massive f**k off pop from my exhaust with a f**kLOAD of smoke, Power FC read 100 knock but the thing is my coil packs failed in that EXACT moment. Its an iffy situation. I'm not going to tell you its not knock and go WOT until something goes wrong but what I would do is change the plugs and give it a couple of runs and see how she goes. If symptoms persist, see a doctor. You can use a cheap method to hear detonation. Get some 4 - 6mm ID rubber tubing, vacuum hose, and get like a small screw, bolt or something you can screw somewhere into the block or in the head of the motor. Stick the other end in your ear hole and put a tissue in your other ear so you can only hear the noise in the tube. This acts like a doctors stethoscope, you will hear knock not as a PING but more a piston slapping a bore which will sound like a thud in your ear. The ping frequency is very high from the outside but the actual sound is around 4900Hz I think.

When Jez was tuning my car, he could hear knock every single time the power FC heard it by placing is head over the engine area and to me looked like he was blocking his ears to isolate the noisy sounds but let the lower frequency noises such as knock be audible. He would then hand signal the dyno man to back off the throttle if he heard knock even though he didn't haha.

I'm 95% sure that it wasn't knock that I heard, but until I'm 110% sure I will treat it like it is.

First thing, as you mentioned, I'll change the plugs. It could be the pump failing, it has been rather noisy (more than usual) when driving recently, but I put it down to hot weather = hot fuel. It's a relatively new Walbro, so while it shouldn't be failing there is that possibility. I've got a wideband, so I will know if it is leaning out.

It didn't surge, it never surged. It just backfired a bit more than usual. I have a high-flow cat and a big exhaust, so I do get the normal popping and gurgling on decel, but it doesn't usually backfire unless cold. And it was definitely HOT. It also sounded different at idle. It's hard to describe, but I know how my car sounds and it sounded slightly different at idle. Haven't driven it since then so I can't say if it has gone away.

Edited December 13, 2011 by Hanaldo

[SargeRX8]

Hot weather, does mean hot fuel which does mean the pump will get hot and being an electrical component, it will run inefficiently when it is hotter than usual hence the louder noise. Hot fuel also can cause the popping sound.

[DVS JEZ]

Does it make the same noise on low boost?

[Hanaldo]

Nope, on low boost it wasn't there. Mind you, I only did one run on low boost because I didn't realize it was intermittent.

[Hanaldo]

Right, finally got round to changing the plugs and the car feels much happier. Took it for a 15 minute drive and it didn't make the noise once, though I don't know if maybe it wasn't hot enough. But at this stage there is no noise so it seems fine.

One thing though... My wideband is telling me I'm running extremely rich. This is before the spark plug change though, so it's not like I've left a hose off or something. After driving for an hour and a half or so on the weekend I noticed the reading towards the end of my trip. At 60-70km/h I'm cruising at about 13.5; at 90-110 it's at 11.5-12 and even got as low as 10.3 for a small amount of time. The car doesn't feel or sound any different though, I would have thought that at 10.5 while cruising it would have been a bit rough or backfiring a bit? Possibly a hose clamp or something? Doesn't have any of the usual symptoms though, the car drives fine on and off boost, it's just the reading on the wideband...

[Rolls]

Right, finally got round to changing the plugs and the car feels much happier. Took it for a 15 minute drive and it didn't make the noise once, though I don't know if maybe it wasn't hot enough. But at this stage there is no noise so it seems fine.

Should still put it on the dyno.

One thing though... My wideband is telling me I'm running extremely rich. This is before the spark plug change though, so it's not like I've left a hose off or something. After driving for an hour and a half or so on the weekend I noticed the reading towards the end of my trip. At 60-70km/h I'm cruising at about 13.5; at 90-110 it's at 11.5-12 and even got as low as 10.3 for a small amount of time. The car doesn't feel or sound any different though, I would have thought that at 10.5 while cruising it would have been a bit rough or backfiring a bit? Possibly a hose clamp or something? Doesn't have any of the usual symptoms though, the car drives fine on and off boost, it's just the reading on the wideband...

Air leak, failed O2 or just poor tune?

edit: On vac an air leak will make you run lean, on boost it will make you run rich.

Edited December 21, 2011 by Rolls

[Hanaldo]

Air leak, failed O2 or just poor tune?

edit: On vac an air leak will make you run lean, on boost it will make you run rich.

It has been fine up until that drive, cruise AFR's used to be 15.5, or around 14.5 at 100km/h.

I'm thinking it may be the O2 sensor has failed, which would be very disappointing given that it is only about 5000kms old.