why is it that you need to run copper plugs with spray? i'm putting my kit on tommorrow, and i got coppers, but my roomate and i were talking about it, and i didn't really know the answer when he asked me......

i'm just wondering if anyone actually knows the reason, or if everyone just puts the coppers in cause someone told them to, like i did......

 

Coppers are okay but Iridiums are where it's at. I ran copper 1 step colder and they were gone after 1 bottle. It was greenish/yellow after the bottle.

 

What it's made of is not as important as the heat range. You need a colder plug because you'll be generating a lot more heat in the combustion chambers and if the plug isn't better able to conduct the heat away, you could get predetonation.

Copper and iridium can also give a stronger spark with less energy than platinums. Iridiums are better than copper because they last MUCH longer and don't oxidize like coppers can.

 

alright, then i'll go get iridiums.......1 or 2 step colder for a 75 shot?

 

The only noticable differences between the coppers and iridiums are the price and the longevity: Coppers are waaay cheaper and the Iridiums last longer. Some say that the iridiums have a stronger spark but if it does, it's too small to notice.

 

75 shot, go 1 step colder.

 

the reason people say copper and iridiums is the same as above. but never run platinum because nitrious reacts with platinium. my .02 cents

 

I've just had a couple of Emails with NX Tech Support about my fried platinum plugs and exhaust valves, and this is what NX had to say:

#1:

Harold,
First, I would recommend not using platinum plugs as they don't react well to nitrous use. This could be the cause of the burnt plugs. Also, have you upgraded anything for the ignition?
What are you doing about the timing? Are you leaving it at the stock settings or are you pulling some timing for the nitrous? This could definately be causing the problems if you have too much timing in the motor.
That's all I can think is causing it right now.

Thank you,


#2

Harold,
I would recommend running an NGK plug that is Steel/Copper or Steel/Iridium. For timing I would recommend pulling 3-4 degrees fromt the stock timing. Also, stay away from multi-tip plugs as they don't tend to work well with nitrous usage.

Thank you,


Interesting .......

 

One of the other reasons as I have been told, is that if the plug is the weakest link in the cylinder, the copper would melt first, and save the piston or valves. Then you can replace the $2 piece without an engine overhaul. As for the other concerns brought up, the general rule of thumb is to go one stepcolder, and 2 degrees retard for every 50 horsepower of nitrous.

 

I looked on the Internet for references to nitrous and melting plugs, and found one comment about the ability of platinum not conducting heat well - about 1/8 or 1/10 of copper! This says to me that the best center conductor is copper, and steel was mentioned as being a better heat conductor than platinum. The iridium tips never melted, but looked like they had been in a really hot oven. One had parts of the platinum ground electrode welded to the iridium tip !

So maybe my platinum-iridium plugs melted because the electrodes couldn't get rid of heat fast enough?? I have a couple of sets of copper-steel NGKs on order, for one and two-step colder heat ranges. The new engine goes in this week , so we shall see.............

Now if there was a good way to reliably retard ignition, I would do that too....

 

J&S Safeguard

 

JWT ECU

 

JWT nitrous program is set for a certain "shot". If you change your shot, it will be off.

 

I use 2 step iridium

 

Calsonic - I looked up the specs on the Safeguard, and especially like this part:

"J&S's SafeGuard has sophisticated mathematical controls or algorithms than discriminate between noise and actual "knock", and has user adjustable controls that allow for sensitivity as well as amount and speed of retard. Whereas OE retard schemes are limited to say 4 degrees, the J&S SafeGurad can be set for up to 20 degrees of ignition retard. This prevents catastrophic failure than can occur should you loose engine coolant or some other unforseen event. The J&S SafeGuard will control the timing of each cylinder in proportion to the degree of detonation occuring, thus maximizing performance and preventing engine damage.

Detonation is the precursor to preignition and only J&S Electronics can provide you a real-time solution to your ignition timing that both maximizes performance and protects your investment. "

The actual connections look pretty simple, but using the Safeguard converts the engine from 6 cylinders firing sequentially (stock) to a repeating 3 cylinder pattern - converting to "waste spark" where the trigger signals of two cylinders from the ECU fire two cylinders at the same time.

My new motor is installing this week, so if it runs, I'm going to get a Safeguard and go to the strip and drive "retarded" with the 35-shot and 75-shot NX stages I used just before melting valves with 35-shot + 100-shot!

Elsewhere the instructions mention a direct connection from your nitrous system to the Safeguard - when you spray, you retard.... and you can dial in how much ignition delay. Pretty slick. Thanks for the clue...

 

I picked up my car this evening - I had a '98 Max 3.0 and an Infiniti VSLD automatic assembled and installed in my '99 Max. It seems to run jest fine, but i haven't put any of the good stuff back on the engine.

There were some leaks around the intake manifold gasket where the MEVI attaches - the installer wondered if this was why I kept frying plugs and eventually an exhaust valve. Too lean, maybe?

He removed the factory studs and replaced them with completely-threaded studs which he Loctited into place. Now spraying brake cleaning fluid onto the gasket while running has no effect - he said before he did this the new engine would die. He showed me the old intake gasket and it was crushed and badly deformed. Strange.

After an oil and filter change, and reinstalling the NX kits and the electronic MEVI controller, I'm ready to try a small shot on the track, and finish learning how to use those 225x50x15 BFG DRs from Dave B.

 

only use iridium. copper has a melting point of 1083.0 °C and a hardness of 3.0. Iridium has a melting point of 2466 °C and a hardness of 6.5.

Copper plugs will break down fast due to the heat, Iridium will last a long time and give you a better spark because it's electrode is smaller. Copper conducts electricity better than anything else, but that means exactly squat when there is megaohms of resistance in the gap of the plug.

 

Ive run nitrous and turbo's on copper NGK plugs, and had Zero issues.

 

mtrai760, a question for you - can you describe how your plugs looked after a big nitrous shot? With my '99, after making a couple of long runs with a 35-shot on launch and additional 50-shot up to 100MPH on the highway on new plugs, the center electrode looks fine, the insulator was bone-white, and the ground electrode was intact but covered with a white, hard material up to the tip! At least they didn't melt this time, like platinum grounds do!

I'm trying the copper-electrode plugs because copper gets rid of heat more quickly than platinum or iridium, and I've slagged down too many plugs.


I'd appreciate anything you can share - thanks.

 

The only problem with your theory is that the piston will melt before you reach the 2466 °C mark. The reason to go with the copper is that it only costs $1.28 to replace. How much is it to replace a piston? If you reach those temps in your combustion chamber, you have a real problem with running lean. Better to replace plug than rebuild motor.

 

Mine were similiar to what you described. Kinda a whitish color along with tip extending down. What you do not want to see is any black specks along any par of the plug after running. What are you using to watch the condition of your engine? EGT, wideband, fuel pressure, etc? When I ran nitrous in my max, I only used Fuel pressure and an EGT gauge, running a NOS dry kit. Those gauges, combined with religous checking of my plugs. I only had detonation once that I could tell, after a hose clamp let loose at my fuel-T at 90psi. I saw the fuel pressure drop, and I let up immediatly, but I have a feeling it was leaking a little before hand. Luckily, none of that fuel hit anything hot in the engine bay Now that widebands are so cheap, I would deffinetly run one of those. Ive never melted a plug on nitrous or boost, I would deffinetly look into that, cylinder temps are getting WAY too hot IMO, you need a little more fuel. I always played it way on the safe side, and probably could have gotten a little more power out of my setups by running a little leaner, but ive never had an engine problem (knocking on wood) 1 year after that fuel hose incident, my car still dyno'd at 180/190 hp/tq. Good luck. Maybe post up some pics of your plugs? What gap are you running? What jet size?

 

Actually I'm using an Aeromotive FPR set to 45psi, pushed by a Walbro 255lph pump, through a new 300ZX filter, and a Jeg's pressure gauge. Pressure stays at 45psi under load. After suggestions, I tried going up-size with the fuel jets, but the problem continued. The insulators did turn brown, though. And I melted about a dozen plugs of all types - even sputtered some platinum ground electrode onto an iridium electrode - looks like a weird sculpture.....

Gaps are set to .035, but I don't think that makes much difference. I have new coils and lots of spark - enough to run with half the ground electrodes burned down to stubs. I pull the plugs after every full-power run, and I use a two-stage NX setup, and the standard NX-recommended jet sizes. Playing with fuel jets didn't help.

It looks like a J&S safeguard, a EGT gauge and a wide-band are in my future. A friend with a Buick Grand National turbo uses just the EGT to tune his 11-second car - but he can re-chip his computer easily. The new engine and setup pulls very well, so off to the Kansas city track this week if the rains hold off.

Thanks for the response - I feel there is something very wrong with the old engine, but I'm starting fresh!