Shifter6

I noticed some people do this. Are the LS7 plugs better? What is the difference?

Toxic c6

I use the ls7/9 in my car. They are suppose to be the same heat range as a tr6 but just a better quality plug.

The Clevite Kid

The GM original equipment iridium spark plugs are very high quality. The heat range for the LS7 is colder than the heat range for the LS2. My LS2 has 11.5 to one compression, and makes LS7 power with a mild cam, milled and ported heads, a FAST 92 and headers, so it needs the colder range plug. A stock or near-stock LS2 should use the GM LS2 spark plugs.

JayplaySS2

I run the ls9 plug for the heat range as well but the tr6 kept setting off charging system
light.

099blancoss

Explain how a spark plug set off the charging system light ??

If your making 100-125 + hp over stock the general rule is to drop one heat range. Be it an expensive iridium or a less expensive copper... there is no difference to the car..

JayplaySS2

You tell me. With tr6's less than 2k miles at idle my voltage would show 11.9 to 12.8 ish. I ignored it for a few months but the scs chime when at a light or slowing down drove me nuts. All I did was swap out to ac delco plugs and as soon as I started it back up my voltage was back to 13.6 to 14.1 and nearly 7 months now not a single scan light. I'm not alone either, the forum brought it to my attention.

Mike Farris

I have TR6s and the service charging system notification goes off all the time. I figure my Procharged car is making the same power as the ZR1 so this plug should be the ticket for me with factory quality.

Wheres the best place to get a set?

099blancoss

My guess is a lose wire or one not on all the way. Same as when a person says the same about an aftermarket wire..... I've seen people say MSD did the same thing but the fact is the MSD has less resistance than the factory wire. A spark plug isnt going to cause a voltage drop.
1000's of people do not see this issue ever... leads me and any reasonable person to believe that isolated cases are not the spark plugs fault. Now I've not tested a bad plug to see the results on car. But one might suspect if the plug is compromised then its grounding out and maybe that is the draw on the system... 100% wild guess right there...LOL

JayplaySS2

I bought mad wires before I replaced the plugs. There is and was no loose wire on the although, starter or harness. All I did was change to ac delco. Done... could have been a bad plug..sure.

JayplaySS2

Damned auto correct. Msd wires.....

RichieRichZ06

FWIW, I have also seen the voltage issue and other misfire issues associated with NGK plugs. It is mush more common on C6's, compared to anything else. I do not have a reason for it either, but we've seen it multiple times here at the dealership.

When the issue's come up, the first thing I do is to inspect the plug for damage, carbon tracking etc. There have been instances where there is nothing visible, but simply changing them out has got rid of the issues and the misfire has gone away.

I do not have a diagnosis for the voltage drop problem, but simply changing from an NGK to a factory plug has made it go away permanently in more than a few cases.

oldmansan

Good to know.

San

Shifter6

So basically the LS7/9 plug is the exact same as an LS2 plug but its one step colder?

eboggs_jkvl

Here's the reason to NOT use the TR6:

http://forums.corvetteforum.com/c6-f...ith-boost.html


I run the LS9 plug because of the FI. I need a colder plug that won't screw up and give me a code.

Elmer

099blancoss

2. Circuit 2540 is supplied voltage from the Horn fuse, position #2 in the UBEC is another reason.. but NGK is mistified by it


I have an NGK tech looking at it.

099blancoss

NGK actually made the plug for GM for 05, they are made by denso now he said.
His going to get the resistance values for me and we'll look at the differences.
The one think he conjectured was material differences... the cheap NGK are nickel plated and the expensive plugs are iridium and platinum.. and due to the tip design he said the plug might be making the ignition system work harder but in no way did he think that would effect the charging system at all. Again, its a spark plug and has nothing to do with the charging system but. I've shown him this thread as well as the others and he will get back to me, I'll post it up.

People are obviously having an issue I told him and the fix was swaping the NGK out so there has to be something.

eboggs_jkvl

Thanks for that. The old "where there's smoke there's fire" thing. I used TR6 on my LS6 Twin Turbo engine and they worked flawlessly. The fussy vette system seems to be displeased with something. The LS9 plug in my car is not giving me any issues.

Elmer

Mike Farris

Just as a follow up. I installed AC 41-104 plugs about a week ago and have not had a service charging system indicator since. I was seeing it several times a day. My TR6 plugs looked fine coming out. I dont know why but they seem to have fixed my issue.

JayplaySS2

It won't return, very odd no doubt.

Shifter6

Should I go with the LS7 plug in my LS2??

Right now my car is a bolt on car, LG headers/Fast102/etc. I may go with a cam down the road. I want to swap plugs before I go to the dyno.