Thread: NGK spark plugs for stock

Just a question.......Does NGK make a spark plug equivalent to our stock ones that is the same heat? Does anyone know the number for them? Thanks

No but if you plan on modding you might as well drop plug heat ranges now and get some Autolite 605's. They are as close to stock as your going to get minus buying AC Delco's.

Originally Posted by Liquifire

Just a question.......Does NGK make a spark plug equivalent to our stock ones that is the same heat? Does anyone know the number for them? Thanks

Actually, yes they do. The TR55 (copper), TR55GP (platinum), and TR55IX (iridium) are all in the same heat range as the stock plugs.

But yes - I would run a 1 step colder plug at a minimum - even on a stock GTP.

Edit: And, little brother - the Autolite 606's are the direct stock replacements.

-Swash

I thought that the TR55's were still one step colder. At least that is what all the other sites say...IIRC...

Originally Posted by bluegtp91

I thought that the TR55's were still one step colder. At least that is what all the other sites say...IIRC...

I could be wrong...but I'm not. NGK is weird on this one - the TR6 is actually their one-step colder plug...where the heat range on the stock plug is actually....6. So it would make sense - and follow the same convention as most of the other manufactures to have the TR5xxxx be the one step, TR4xxx be the 2 step, etc etc etc.


-Swash

Where's that damned "blah blah blah" smiley LOL

Originally Posted by bluegtp91

Where's that damned "blah blah blah" smiley LOL

I dunno...but I found this one while I was looking for it...




-Swash

OK...so TR55's are stock........Tr6's are one step colder? and the TR4's are two steps colder? That labeling system makes no sense.........but if you are right........great. Thanks.......

Honestly...I say get Autolite 605's. I DO KNOW that they are 1 step colder than stock and help you get rid of KR a little bit more...just a thought since they are basically thre same price

what about autolite 104s that everyone seems to like? how much colder are they?

NGK TR55 are actual about 1/2 step colder.

I run the TR55IX iridium plugs and couldn't be happier. DON'T go with NGK TR6 plugs because they run to cold 1.5x colder and your mpg will drop for being stock. I've used both plugs and went back to TR55IX with my current mods.

Originally Posted by JJ91284

NGK TR55 are actual about 1/2 step colder.

Originally Posted by Jakegday

what about autolite 104s that everyone seems to like? how much colder are they?

They are one full step...I went through them in the safely modding your 3800 thread...and then the TR6's are inbetween them and the autolite 103's...which are for people with crazy setups...

what is the difference between iridium and platinum as far as what is the application difference? When is it more beneficial to switch from platinum to iridium? Thanks

Facts

Good Platinum are rated at approx 100k miles (I wouldn't run them this long)
Iridiums rated at approx 60k (I wouldn't run them this long, they have extended life versions which are suppose to be on par with platinum)
Iridiums 6 times harder and 8 times stronger
Platinums not to be use with Nitrous
Iridium has 1200F higher melting point than platinum

I personally change the plugs at half the recommended mileage, usually because thats when I check my belts and swap them out along with fuel filter, and fluids.

Originally Posted by JJ91284

NGK TR55 are actual about 1/2 step colder.

I run the TR55IX iridium plugs and couldn't be happier. DON'T go with NGK TR6 plugs because they run to cold 1.5x colder and your mpg will drop for being stock. I've used both plugs and went back to TR55IX with my current mods.

Technically - yes, but NGK always has shown them to be the direct heat range replacement for the L67/L36. X2 on the TR6 - my MPG noticeably dropped when I ran them, too. I don't have any experiences with platinum plugs - I tend to stay away from them.


-Swash

I hate to revive this thread, but personally I have been running the copper 104's and they worked great with me. My friend just bought this car from me and he doesnt want to bother with copper plugs. Which iridium plug is the same heat range as the AL104's? He will only consider these iridium plugs so no other recomendations please. I know I saw an actual chart comparing these heat ranges somewhere between some major brands but I did a search and can't seem to find it anywhere. Thanks in advance. I have the basic 3.4 setup on the car with mods listed in sig....

No Iridium plugs for modded cars.

They suck.

dammit, you sold your car? weak.

Originally Posted by bluegtp91

No Iridium plugs for modded cars.

They suck.

I agree... but not my choice anymore... I assume that the 55's would be the correct range( about a half range hotter) or the 6's would be a half range colder than the AL104's?