macattack0821

So I'm replacing the spark plugs in my 01 TA, and from reading on the forums it seemed most recomended NGK TR55's for a lightly moddded LS1 (mine has headers and a cat back). Went to the store and happened to get into a conversation with one of the guys there, and he recommended to go with the TR6 plugs. From what I had read, those plugs were best suited for a nitrous/FI setup. Long story short, I ended up going with the TR6's after this conversation. Wondering if ended up buying the wrong plugs...anybody with a little more knowledge care to point me in the right direction?

Randolph Ziskey

iTrader: (13)

From what I researched the tr6 is one step colder than the tr5(stock recommended), the tr55 is half step colder than the tr5 (stock recommended). I currently have the tr55s on my car but did buy tr6's because I went turbo. Just haven't had time to swap em out and so far the the tr55's are holding up and haven't had any problems. Someone correct if wrong.

saltwatercowboy6355

iTrader: (1)

The TR5 and TR55 are the same heat range but have different gap. The TR6 is a step colder than the previous. This has been my research and say a thread that had info from NGK's site confirming this. I cannot say that the TR6 plugs are right or wrong for you as I have only used TR55's with what's in my sig.

Randolph Ziskey

iTrader: (13)

^^^^^^corrected on the gap for tr5 and tr55's

https://ls1tech.com/forums/generatio...r5-vs-tr6.html

https://ls1tech.com/forums/generatio...k-tr5-tr6.html

https://ls1tech.com/forums/generatio...r55-plugs.html

http://www.ls1gto.com/forums/showthread.php?t=243764

https://ls1tech.com/forums/generatio...-ngk-tr55.html

macattack0821

My experience from reading about the TR6's was the same, that they were a step colder than the TR5's or '55s. Hoping somebody will be able to clarify whether or not they can be run without issues on my car...I'd hate to waste all that money.

joecar

They will be fine.

vettenuts

iTrader: (4)

TR5 and TR55 are the same heat range. The second "5" designates a larger gap. Since GM changed the gap via TSB on some plugs, I wouldn't run the TR55 anyhow.

The TR5 and TR6 are the same gap, but the TR6 is one step colder.

I wouldn't worry about them too much. Run them for a while and if the car runs OK, pull one of the front easy to reach plugs and see if it is getting too much carbon on it.

Better one range too cold than too hot.

diaz90220

we used to use TR5, but since TR6 are just a bit colder we run these now, we set the gap at 35 which was been the best set up we have found as of late.

kinglt-1

iTrader: (26)

TR-5 - Stock heat range .039 gap

TR-55 Stock heat range .059 gap

TR-6 1 step colder

-Stock, Full bolt-on, or H/C/I cars up to 11:5.1, the TR-5 is fine.

-High compression 11:5.1 +, Forced induction, or small shot of Nitrous(100 or less)... TR-6

-Big shots of Nitrous( 150 or larger), and high boost FI setups, the BR non projected tip plugs are advised.(BR7EF-BR8EF-BR9EF depending on power level).

macattack0821

Sounds like something I can do, my big worry is that they would start throwing codes because they weren't meant for my application right now

*Edit*---What is the stock gap for plugs on the LS1? Shame on me for not knowing but it's just not coming to me at the moment

macattack0821

All the info you just posted is how I understood it....TR5 for light mods/bolt ons, and TR6's for a nitrous or FI set up. Do you think they will run OK in my set up right now?

kinglt-1

iTrader: (26)

You are fine...they "Might" foul quicker, but that is it.

macattack0821

Awesome, thanks for the help guys!

spawne32

iTrader: (2)

You cannot go by what kind of mods you have done entirely, you have to visually inspect the plugs. Generally speaking you can determine how hot your plug is getting just by looking at the threads and the tip. Like all metal, when it reaches a certain temperature it begins to change color from heat, you should only see discoloration of the metal at the closest point to the firing end where heat is greatest. If the plug is starting to discolor (turning yellow or straw color) beyond the first 3 threads, the plug itself is getting very hot. Another way, but slightly less accurate is to look at the ceramic around the firing tip, if the ceramic remains bright white, then it is running hot as well, the ceramic portion should begin to change to a slightly darker shade of off white towards the very very light brown/tan color on the proper heat range after a couple of passes.

That being said, if your not getting detonation, its better to run the plug as hot as the car will handle not only for emissions reasons but youll get a nice clean burn. Often times guys go to the TR6's, like I had to do because we just can't get around the KR once the plug gets hot on track passes. There is always a trade off depending on what heat range you go with, just like there are always trade off's with running bigger cams.

Cylinder temperature is the only direct way to determine what plug heat range you need correctly, but since we can't measure that, we can only speculate based on the gradual increase of horsepower, and increases in horsepower are direct increases to combustion pressure and temperature.

kinglt-1

iTrader: (26)

Yes I agree but you must have some sort of guideline to go off of initially to get you close. Then you read the plugs and adjust heat range accordingly.

lsxsleeper

Several buddies as well as myself always run tr6 plugs gapped to 35 thousands run great with no issues

RPM WS6

iTrader: (3)

Stock gap for the factory platinum tip plugs was .060". I've used TR55s with gaps in the .050-.060" range without any issues, stock internal + bolt-ons or mildly cammed. The TSB that calls for a smaller gap (.040") was specifically for the GM iridium tipped plugs released around ~2003 as a service replacement for the platinum plugs.

dailydriver

So should ANY iridium tipped center electrode plugs (NGK Lasers/IXes, Densos, AC Delcos, yes which are made by one of the other two companies I've listed) be that same .040" right out of the box as well??

Darth_V8r

iTrader: (4)

this what I run, but I chose them for the higher compression. I chose 035, because I didn't want to risk blowing the spark out. Not necessarily one size fits all, but it fits quite a lot.

RPM WS6

iTrader: (3)

I really can't say for sure, as I don't have any data direct from anyone but ACDelco. The bulletin number was 03D-J-171 if you wish to look it up, but the key information in the bulletin is the following:

"A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed. The new spark plug, ACDelco Part Number 41-985 (12571164), is gapped to 1.01mm (0.040 inches) when the spark plug is made. The spark plug gap is set during manufacturing and should not be changed to the gap required with the Platinum plug, or damage to the spark plug may result."

No updated plug gapping requirement was ever listed/issued for the engines themselves, only a change in gap for this specific new plug itself.

Having said that, another bulletin was released in May of '13 (13D-070) stating that platinum plugs would again be offered in place of the iridium tipped versions for 2006 and older applications that were previously serviceable with said iridium tip. Reading the document, this seems to have more to do with price concerns rather than any "improvement" by going back to the platinum tip. No mention was made of gapping in this bulletin.

IMO, for those using conventional tipped plugs in the stock heat range (such as NGK TR55), the majority of stock to moderate applications will benefit from using something close to the larger original gap size.