>Nitrous spark plug experts in here<
Thread Starter
TECH Apprentice
Joined: Oct 2003
Posts: 396
Likes: 0
From: Lumberton, TX
>Nitrous spark plug experts in here< Can any of you look at this plug and tell me how you think it looks. It's a TR6 plug. Sorry for the less than perfect pics, I didn't have my camera with me.
Well, if my eyes arent deceiving me:
The mark on the ground strap is b/w the curve and the base, thats kind of high. Less timing would help bring it more towards the curve itself.
Bleached white porcelain is normally result of running too lean. If its powdery white its way way too lean, your looks just lean enough to bleach it off.
The speckles on the face of the plugs body (the flat surface at the end of the threaded portion) has what appears to be some speckling from detonation. It should be smooth and slightly carbon sooted. Any formation of debris, is actually minute pieces of the pistons breaking off during uncontrolled ignition (detonation). Also indicator of low octane, too much advance, too lean.
IF the plug was run down a WOT blast, or track run, then the car shut off and the plug pulled without driving back to the pits, thats what I would think. If you pulled the plug AFTER driving down the return road to the pits, then toss the porcelain part, and pretty much the timing mark on the GS, however the speckled facing wont change, its still pieces of the piston!
My recommendation, reduce timing 2-3*. Make a run and check immediately after shutting down after the turn off to the return road. By reducing the timing you will slightly richen the AFR, maybe enough to return the porcelain to a bland white/slightly beige color. Also the timing mark should move towards the end of the GS slightly rather than so close to the base. And finally, wipe off all debris on the face before you make the run to ensure there is no pre-exposed debris.
GL,
Charlie
The mark on the ground strap is b/w the curve and the base, thats kind of high. Less timing would help bring it more towards the curve itself.
Bleached white porcelain is normally result of running too lean. If its powdery white its way way too lean, your looks just lean enough to bleach it off.
The speckles on the face of the plugs body (the flat surface at the end of the threaded portion) has what appears to be some speckling from detonation. It should be smooth and slightly carbon sooted. Any formation of debris, is actually minute pieces of the pistons breaking off during uncontrolled ignition (detonation). Also indicator of low octane, too much advance, too lean.
IF the plug was run down a WOT blast, or track run, then the car shut off and the plug pulled without driving back to the pits, thats what I would think. If you pulled the plug AFTER driving down the return road to the pits, then toss the porcelain part, and pretty much the timing mark on the GS, however the speckled facing wont change, its still pieces of the piston!
My recommendation, reduce timing 2-3*. Make a run and check immediately after shutting down after the turn off to the return road. By reducing the timing you will slightly richen the AFR, maybe enough to return the porcelain to a bland white/slightly beige color. Also the timing mark should move towards the end of the GS slightly rather than so close to the base. And finally, wipe off all debris on the face before you make the run to ensure there is no pre-exposed debris.
GL,
Charlie
TECH Junkie
Joined: Aug 2002
Posts: 3,726
Likes: 0
From: Fort Collins, CO
Here's the deal. You CANNOT read that spark plug. Anybody who thinks they can read that plug doesn't know what they're looking for/at. You need to cut the threads off of that plug and then take a high quality picture with the flash off. Try to get a high quality camera and use Macro mode when you take the picture. Make sure there is a lot of ambient light, don't use the flash.
You don't even need to go that far to know that plug is a little too hot for a serious nitrous pass.
Switching to a race design plug that's colder and non-projected tip will kill at least two birds with one stone. A shorter tip will have a small effect similar to running a degree or two less advance.
If you're only getting slight speckling, then chances are you have a little detonation happening on the big end of the track when those plugs have had time to build considerable heat in the tip. A race type plug will stay cool on the big end and be much less likely to be a source of detonation itself.
The Autolite AR472 is my plug of choice for your application, but there are equivalents in other brands as well.
Look for a short porcelan, a short but fat ground strap, and avoid the plugs with the screw-on terminals. I also have a preference for non-resistor models, but either will work.
HTH
Switching to a race design plug that's colder and non-projected tip will kill at least two birds with one stone. A shorter tip will have a small effect similar to running a degree or two less advance.
If you're only getting slight speckling, then chances are you have a little detonation happening on the big end of the track when those plugs have had time to build considerable heat in the tip. A race type plug will stay cool on the big end and be much less likely to be a source of detonation itself.
The Autolite AR472 is my plug of choice for your application, but there are equivalents in other brands as well.
Look for a short porcelan, a short but fat ground strap, and avoid the plugs with the screw-on terminals. I also have a preference for non-resistor models, but either will work.
HTH
couple of pics for illustration.
http://www.geocities.com/tpigirl89/AR472vsStockd.jpg
http://www.geocities.com/tpigirl89/plughotcold.jpg
http://www.geocities.com/tpigirl89/AR472vsStockd.jpg
http://www.geocities.com/tpigirl89/plughotcold.jpg
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It would be too hard to say looking at it via the net. I have to look at mine in a highly lit area with a magnifying glass to get an accurate idea of what is happening. Another thing that makes plug reading difficult is that after a pass unless you turn it off right then and pull off, pop the hood and pull the plugs you can get a false reading. The reason I say this is that while driving normally back to the pits without the use of the nitrous the evidence of what it actually happening is typically burned away by the drive back unless it is something drastic. If you truly want to read the plugs make a pass and then shut off the car as SOON as possible and get them out. This will give you a more accurate picture. Hope this helps.
Jim C.
Jim C.
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