How often do NGK TR-55s need to be changed?
Thread Starter
9 Second Club NA
iTrader: (180)
Joined: Mar 2003
Posts: 5,943
Likes: 1
From: Houston, TX
How often do NGK TR-55s need to be changed? Ive had them in there for quite some time now and was one of the first few mods that I did to the car. I wish that I would of wrote down when I changed them out, so now its leaving me guessing. If they do need changing, should I replace them with the same plugs or is there something better out there? The NGKs seem to be a very popular plug, but how come theyre so cheap? Are there any plugs out there that will out do the TR-55s, no matter the cost? What about the NGK Iridiums? Ive come across those before. Ya know how the more something performs, the faster it wears out...for instance: the more a tire sticks, the faster it wears. So does the better the plug performs, the faster they wear out? Is there a certain tq spec that the plugs should be set at because I know that you can overtighten them? Lastly, is it true the more power/hp you add to the motor, you should change the gap? I think I read somewhere for every 50hp you add, you do this...?? Ive added 160+hp to the car, should the gap be changed or stay the same? Thanks and sorry for all the questions, but any and all help is much appreciated! 
TECH Resident
Joined: Nov 2002
Posts: 857
Likes: 0
From: Orlando
Re: How often do NGK TR-55s need to be changed? I replaced mine between 20 and 25K. I can't say that in other than F/I or nitrous cars that plug gap is a real big issue with regard to adjusting for more power. It may be, I just have never heard of that being an issue.
TECH Resident
Joined: Nov 2002
Posts: 963
Likes: 0
From: AustinTexas
Re: How often do NGK TR-55s need to be changed? They do need to be changed more often because of the copper tips. The reason the stock plugs last so long is because they have platinum tips. The copper tips wear out faster.
Re: How often do NGK TR-55s need to be changed? I changed my stock plugs out at 14,000miles with Bosch Platinum +4's. They're a little more expensive than the regular side gap plug, but I'll take four electrodes instead of one. I have heard alot of good things about them which is why I bought them. I used to use NGK plugs on my 86' SVO Mustang in the 80's, and never really cared for their quality, but for those that use em' more power to you.
Re: How often do NGK TR-55s need to be changed? i change my tr55's every 2 oil changes (roughly 7000 miles)
probably overkill but it only cost like 13 bucks and takes 30 minutes
probably overkill but it only cost like 13 bucks and takes 30 minutes
Trending Topics
Re: How often do NGK TR-55s need to be changed? Think i put 25K on my last set. Looked great when i took them out.
I also drive my car everyday!
Change my oil religiously Q 6K (Mobil 1) Anyway, can't go wrong @ $14.00 set (Oreilly Auto)!
My .02 FWIW.
I also drive my car everyday!
Change my oil religiously Q 6K (Mobil 1) Anyway, can't go wrong @ $14.00 set (Oreilly Auto)!
My .02 FWIW.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
9 Second Club NA
iTrader: (180)
Joined: Mar 2003
Posts: 5,943
Likes: 1
From: Houston, TX
Re: How often do NGK TR-55s need to be changed? I plan to replace them with the same plugs just for the fact that Ive heard nothing but good about them, and that so many people use them. Another thing that I was wondering is...if theres a better plug that I could replace it with. I know that cost doesnt make a product better (thats totally true for NGKs because theyre so cheap, but good!), but is there a plug out there that will outperform the TR-55s? While were on that note...what are the NGK Iridiums? Ive heard of them here and there, but what are they all about? So anyway, I was just curious if I should just stick to what Ive got, or is there something that I should try out/consider? Thanks for all your input guys!
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
Re: How often do NGK TR-55s need to be changed? I'll stick with my TRs. You can't beat copper for performance.
About the mulitiple electrodes gimmick. The spark can only use ONE path at a time (it follows the path of least resistance.) You'll have ONE spark regardless of if you have one electode or 10. Just something to think about.
About the mulitiple electrodes gimmick. The spark can only use ONE path at a time (it follows the path of least resistance.) You'll have ONE spark regardless of if you have one electode or 10. Just something to think about.
Thread Starter
9 Second Club NA
iTrader: (180)
Joined: Mar 2003
Posts: 5,943
Likes: 1
From: Houston, TX
Re: How often do NGK TR-55s need to be changed? Colonel: Do you know of any other companies that make copper plugs and if so, are they any better than the NGKs? Do I need to change the gap at all since Ive added 160+hp? Ive read somewhere that you had to change it so much for every 50hp. This has all been done with bolt-ons, cam, and tuning. Thanks
On The Tree
Joined: Oct 2002
Posts: 120
Likes: 0
From: Albuquerque
Re: How often do NGK TR-55s need to be changed? I swapped the factory plugs for the tr-55's about 7000 miles ago and recently noticed a slight miss at WOT (high revs). I put the original stock plugs back in and the symptom seemed to go away.
Thread Starter
9 Second Club NA
iTrader: (180)
Joined: Mar 2003
Posts: 5,943
Likes: 1
From: Houston, TX
Re: How often do NGK TR-55s need to be changed? Anyone have anything to say about the NGK Iridiums? Are they any better than the TR-55s? How much are those? I havent heard or read much about them, but Ive come across them a time or two. Is there a better plug out there to replace the TR-55, or should I just stick with 'em? Thanks
Re: How often do NGK TR-55s need to be changed? just stick with tr55's copper...and treat them like a regular maintenence item...its a relatively easy thing to do.....just change them every spring when you give the car a once over for everything else.
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
Re: How often do NGK TR-55s need to be changed? Many companies make copper plugs but I haven't tried them all. I know the NGKs work great for me and everyone else so I see no reason to change them.
It's just a spark plug. It doesn't MAKE power. It just lights a fuse...it sparks. Don't get so hung up about it. Whether you pick the absolute best plug isn't going to make enough of a difference that you'd ever know it on the dyno.
Stock gap is .060. Anywhere between .035-.055 will work fine with an engine making an extra 2-200 HP. Take your pick. Me? I'd gap a TR-55 at .050. Plug gap just isn't very crucial with our ignition systems simply because they're overkill. They have one coil pack per cylinder.
But yes, the general rule of thumb is to decrease it by .004 for every 50 HP added. So, that would bring the stock .060 down to .0472 if you added 160 HP.
It's just a spark plug. It doesn't MAKE power. It just lights a fuse...it sparks. Don't get so hung up about it. Whether you pick the absolute best plug isn't going to make enough of a difference that you'd ever know it on the dyno.
Stock gap is .060. Anywhere between .035-.055 will work fine with an engine making an extra 2-200 HP. Take your pick. Me? I'd gap a TR-55 at .050. Plug gap just isn't very crucial with our ignition systems simply because they're overkill. They have one coil pack per cylinder.
But yes, the general rule of thumb is to decrease it by .004 for every 50 HP added. So, that would bring the stock .060 down to .0472 if you added 160 HP.
TECH Resident
Joined: Jun 2003
Posts: 862
Likes: 1
From: Los Angeles, CA
Re: How often do NGK TR-55s need to be changed? another thing to consider concerning those four electrode plugs. sure they choose one path only, but when the path of least resistance starts to get shitty, it can take the next best one, right? then it should last 4x longer, right? WRONG! look at the other side of the spark. how crappy! look at the NGK. wow. the bosch has like a needle for a center electrode. the NGK has some split (why?) electrode that is way fatter. all you need is a little speck of corrosion to completely cover the bosch.
Launching!
Joined: Mar 2005
Posts: 229
Likes: 0
From: cobourg ON
spark jumps best from an edge or corner therfor the more spikes or edges you have on the center electrode the better or longer theplug wil last theoreticly. on the other hand the spark lands best on an edge as well so really overdoing the outside electrode with 4 spots doesnt matter really if the center is worn out either way just stop being so frugal and replace the plugs normally and you wont have any problems capiech
