I used Champion cooper plugs with nitrous for awhile I'm using NGK coopers now. I had Denso Iridium, NGK Iridium and NGK Platiums. They all seem to work fine in the VQ NA wise. I had problems with Iridium on nitrous. For some reason, Bosch platiums just don't work well in Japanese engines. I had problems with them in the past like the white insulator part cracking and falling out in the engine. I stop buying them.

 

I am not saying that the plug is the only reason why my engine blew but cnsidering that I bought those plugs the same day I went racing and having that particular one from the dead cylinder look that bad (see above pictures) makes me think it has something to do with it. My theory is that if a step colder plug reduces the exhaust tempratures 80 degrees and I needed to run two steps colder then the temprature was about 160 degrees hotter than it should be due to the fact that I was running stock plugs. And keep in mind that my engine has over 193k miles in it so I would only guess that the interior parts are in less than prestine conditions.

 

Yeah, the +4's had missing prongs on some cars. I didn't have any issues when using them and ran my fastest NA times on them.

 

I had the same experience putting Bosch plats in my 92 Exploder. The explanation floating around the rec.autos.exploder newsgroup at the time was that Bosch plats were not good in cars with a distributerless ignition system. Something about the current changes direction from one spark to the next with a distributerless ignition and the Bosch plugs don't like that. Why would that be? Anyway, after that experience, I have never used Bosch plugs.

 

What about Iridium plugs? I have heard that you might want to use Iridium plugs if you are using a turbo, a supercharger or Nitrous. I heard that the Iridium plugs can withstand the pressure and temprature increase with forced induction alot better than copper or platinum.

I may be wrong though.

 

How long had you been running the 75-shot? What plugs did you use previous to that day?

Once you swap engines, pull the blown piston and it won't be hard to figure out what happened, ie detonation from running lean or pre-ignition from a hot plug tip or other hot-spot.

 

I did not run any higher than 50 until that race and the 50 shot was with the platinum plugs. When I pulled those platinums out they were in pretty bad shape too.

 

BTW I can't pull the blown piston out of the blown engine cause I have to trade that engine in to get the other one it has 41k miles for $550 with trade in only.

 

No...no...no.

The iridium plugs I've seen use a fine wire which creates a spark from less voltage due the thinner electrode Iridium allows, ie great for underpowered ignitions. However, copper plugs require a smaller gap, yet produce a fatter spark, which is less likely to be blown out by forced induction and cause misfire.

The ONLY advantage the harder metals such as iridium or platinum or whatever have over copper is that they can withstand the abuse longer, ie don't wear away as fast.

So, for the OPTIMAL spark use copper with the proper gap reduction and make sure you replace them when necessary.

As asuboy said, "platinums are for lazy people" and I'll say, Iridiums are for Honduhs weak electrical systems.

 

I'm going to say it again. Your fuel system, whether it be clogged fuel filter or injectors or a weak fuel pump is to blame. You were probably lean with the 50-shot and went catastrophic lean with the 75-shot.

You can still pull the head and look inside at the piston. It's all about the labor you care to do.

 

246
135
||
\/
Front of car


That's the cylinder order, are you sure it's #4 that's dead?

 

actually I think its
135
246
||
\/
front of car
but if I'm wrong then its #3
And btw you do make a good point about the fuel supply since I was running the stock pump even though I had new injectors and filter but if you look in the nitrous forum, people have ran 75 with stock pump and no problems. My point is that higher than normal tempratures in the combustion chamber cause detonation and the stock plugs were producing higher than expected tempratures and therefore causing the fuel/air mixture to combust prematurely. Whereas if I had used two steps colder plugs, then I would have avoided the extreme tempratures. Of couse another variable is the wear and tear of the interior parts brought on by a age and constant abuse.

 

Unless not all 4th gens. are the same, it's:
246<--Fuel IN
135-->Fuel OUT
||
\/
Front of car

So, #3 or more likely #5 was my guess to go lean FIRST. If you tear it down, #5 will probably show signs of detonation also. #3 just let go first.

Anyways, all fuel pumps capacity over time are different and with as many miles as you had, that fuel pump couldn't even support the 50-shot. You just didn't know it.

Once you get the new motor in, pull the fuel pump and either A)Filter is clogged up bad or B)Pump is weak or C)probably both!


Super heated intake charge *MAY* cause an increased tendency of detonation depending on fuel antiknock ability, however a proper proportion of air AND fuel by a wet shot will actually reduce intake charge temperatures. It's the more potent combustion that causes increased combustion temps.. Colder plugs will somewhat lower combustion temps., however NOT drastically enough to offset too lean of an A/F ratio. Colder plugs MAJOR function is to reduce plug tip temperature just enough to minimize it as a hot-spot for a pre-ignition point. Two steps colder plugs would NOT be able to prevent pre-ignition if you run super lean.

 

sounds like a nitrous backfire to me, I know the NX kits have worked flawlessly for many members on this board and I am not saying anything bad about the kit, but I have seen it happen before so the possibility is there, but it does look like he was running lean.

Also I use 1-step colder ngk coppers with no problem on the 85-shot, but that is a dry kit and doesnt really aplly to him.

 

Charles I feel soo bad that we took off, I had no idea about your motor blowing til a few hrs ago. The plugs were not the problem ill tell you that, im pretty sure (very sure) it was a fuel problem you had. Im sure you remember when I saw your setup I was kinda shaken up a bit, it looked risky not to mention the lack of guages. You basically had no idea of what the A/F ratio was and that night it was pretty warm so every1s bottle pressure was quite high, but once again you had no idea how high yours was (no guage) Thats what made me kinda hesistant about your setup. I really wish I was still there to help after it happen, with the track that packed, I cant imagin how long it too for you to get home man. (I gave you my cell# a while ago too )
Im not trying to make this sound like an I told you so response, you dont need that right now but my bet was you ran lean as hell with your bottle pressure sky high.
Goodluck man.