TR-6 Plugs
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Joined: Dec 2001
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From: Germantown, MD
TR-6 Plugs Hey guys I got a couple of questions about plugs. I'm messing with the car so I figured since TR-6s are cheap is it a good idea to go ahead and replace them after only 8K miles? I pulled the #2 plug and it looks fine. But for under $16 I can replace all 8, so it's not that big a deal if there's an advantage.
Does anyone know a NAPA or pepboys part number? I ask cause I took the plug into NAPA and the dude couldn't figure out which kind I wanted. I'm thinking maybe either NAPA doesn't sell em, or they package them with a different part numbert than "TR-6".
Also on a slightly more theoretical note, can someone explain why a TR-6 is better for FI cars than say the Iridium plugs which cost significantly more? This is one of the rare occations where being an FI owner actually saves you money! I know the TR-6 has a "cooler" spark. But I'm hoping someone can explain, in somewhat laymen's terms, how a spark can be cooler or hotter?
Thanks,
Mike
Does anyone know a NAPA or pepboys part number? I ask cause I took the plug into NAPA and the dude couldn't figure out which kind I wanted. I'm thinking maybe either NAPA doesn't sell em, or they package them with a different part numbert than "TR-6".
Also on a slightly more theoretical note, can someone explain why a TR-6 is better for FI cars than say the Iridium plugs which cost significantly more? This is one of the rare occations where being an FI owner actually saves you money! I know the TR-6 has a "cooler" spark. But I'm hoping someone can explain, in somewhat laymen's terms, how a spark can be cooler or hotter?
Thanks,
Mike
Usefull reading on the topic of heat ranges...
http://www.ngksparkplugs.com/techinf...00&country=US#
http://www.ngksparkplugs.com/techinf...00&country=US#
Thread Starter
TECH Fanatic
Joined: Dec 2001
Posts: 1,220
Likes: 0
From: Germantown, MD
Originally Posted by PongoX11
Napa should be able to find it by NGK part number: 4177
Harlan, I understand the part where they talk about the insulator nose length being related to the plugs optimal thermal range. A longer nose, means more surface area, means it will retain more heat, which means it's a hotter plug. So all this time I thought the fact that the TR-6 was a copper plug vs. my old TR IX Iridiums was what made the difference, really had nothing to do with it. They didn't really go into how the different types of metals alter plug characteristics.
The part that confused me was how the colder plugs dissipate heat more quickly than the hotter plug. To be honest, I was totally unaware that one of the spark plugs main functions was to remove heat from the combustion chamber. The part that confuses me is how the spark plug's dissipate the heat? The article says, "The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling system". Making it almost sound like the spark plug comes in direct contact with the engine coolant, which I'm pretty sure it does not. Also, why would a colder plug, with less insulator nose length, be able to transfer heat faster than a plug that runs hotter?
Can Harlan, or anyone else for that matter, clear up the heat exchange thing?
Thanks,
Mike
The best I understand it, with less insulator length theres more heat that makes it into the body of the plug. Since the plug is in direct contact with the head and is surounded by coolant more heat makes it into the coolant. Never had to take heat transfer as an EE so i'm guessing here 
But if you think about it, with more insulator the center electrode should hold more of the combustion heat.
I've always stayed with solid ground electrods after seeing some of the wierd center core stuff melt out on the dyno at work, or see the platinum discs melt off.
I've tried the 8 heat range stuff, but they foul out FAST. Only on the dyno however. I've got a set of 7's to go in, but until now I've been using 6's and watching them VERY carefully. I only use a set for maybe 2 passes then swap. I've had 6's melt on me before at a much lower power level, but i was running more advance and less fuel then. I'm keeping the EGT's in the 650°C range with fuel now, and the plugs seem to live. But then again most people don't run 8 EGT's for datalogging
But if you think about it, with more insulator the center electrode should hold more of the combustion heat.
I've always stayed with solid ground electrods after seeing some of the wierd center core stuff melt out on the dyno at work, or see the platinum discs melt off.
I've tried the 8 heat range stuff, but they foul out FAST. Only on the dyno however. I've got a set of 7's to go in, but until now I've been using 6's and watching them VERY carefully. I only use a set for maybe 2 passes then swap. I've had 6's melt on me before at a much lower power level, but i was running more advance and less fuel then. I'm keeping the EGT's in the 650°C range with fuel now, and the plugs seem to live. But then again most people don't run 8 EGT's for datalogging
[QUOTE=y2khawk] until now I've been using 6's and watching them VERY carefully. I only use a set for maybe 2 passes then swap. I've had 6's melt on me before at a much lower power level, but i was running more advance and less fuel then.[QUOTE]
damn, mine been in for about 10k miles now.. i should have a look
damn, mine been in for about 10k miles now.. i should have a look
