It's been a while since I've been involved in a spark plug thread, so here goes!

Many of you will remember the plug debates of 1998! Back then I ran NGK TR6s gapped at .044, with good results. Yesterday when I was getting my car dyno tuned, the first run showed 7 degrees of KR, so I pulled a plug and it looked pretty awful, even with under 33k on the car. So I decided to swap out the plugs before making another pull. I was going to go with TR55s, but ARE only had TR55 platinums in stock, so I went with the TR6s instead. I gapped them to .050.

I remember when I ran them on my 98 Formula, they fouled out and started misfiring in just 13k. So my question to you guys is how long do you find they are lasting you before you run into misfires? I will probably swap them for TR55s in the fall just to be safe, but might go back to TR6s again next summer. The plugs are so easy to change on the C5 by the way! Even on a hot motor, I had them done in well under an hour. On a cold motor I could easily cut the time down. None of the plugs are hard to reach at all.

 

I had TR6's in my LT1 and I am getting ready to replace them with TR55's because I took my nitrous kit off. I think that the TR6 is a pretty cold plug for a NA car. I think that the TR55's gapped at about .045 to .050 will do best, JMO.

 

On a stock motor, I think the TR6s are too cold. I ran them on my stock motor when I was spraying them and the car didnt feel the same N/A. It felt a little sluggish. Even with my 11:1 compression and hot FL air, Im running TR55s with no problems.

 

I never noticed my 98 Formula feeling sluggish with TR6s, and ran my best ET with those plugs in place, a 12.68 at 110.6, which was a very good time for such few mods (ported stock MAF, MTI airbox, cutout, HPP3 tuning, 4.10s, drag radials)

I bought some TR55s today though, and will eventually swap them in but I'm still going to run the TR6s for a little while.

 

I switched from TR55's to TR6's this past Easter weekend, when the compression went from 10.77 to 11.25:1. Don't know if I needed them, but Paul @ Thunder thought it was a good idea. I left them gapped the way they came out of the box.

So are there longevity issues with them?

 

I'm about to pull my TR6s installed with my H/C, car was running lean for a while and I want a fresh set. I'll check them out for wear when I put the new TR6s in. I plan on gapping them to .45, because I don't run Nitrous.

 

So what do you think would be better for my car because I'm about to get a set. TR-6's or TR55's?

 

Another thing I should mention is some of the info I got from NGK's website. They say you should go one step colder when you add 75-100hp to the engine. Also, if you run more timing, or run leaner, you end up elevating your combustion chamber temps, so a cooler plug is helpful too. Higher compression also elevates cc temps too.

 

99'Formula, you should probably run the TR55's. The TR6's are normaly used on cars with nitrous or a blower that need colder plugs.

 

n20, thanks i'm going to be swaping them out when I do the cam install.

 

It being so hot over here and high humidity KR was an on off problem. When I started shooting N2O dry , I went with TR6 gapped .040
KR N/A now is non existant, and no fouling issues but I change mine twice a year.
With them and 98 octane gas, I can run the 5177 NOS without jets and full timing at wot 28.5>30.1, no detonnation whatsoever and great track times.
Never feels sluggish.

 

I have been running tr-6's for a year now with my 50 shot...no problems

 

TR55s when my car had just a cam, never had any issies with them

Now running TR6s gapped at .035 with a prochrager @8lbs. Seems to be working out well together

 

125 shot plugs gapped at .38. and i know that is not the best gap so someone tell me how they should be gapped and what the gap has to do with perfomance please thank you.

 

you dont want to gap a plug more than like .05 from which they are set at... you start bending the electrode out of shape... i ran my TR6s at .04 and .035 never had any problems either way

 

I would run TR5's for a stock NA application with boltons. Stock gap is .060, so I would go .045-.055 with them.

I would run TR6's with power adders, or motors that have a lot of added compression or timing. I would run most power adder TR6's gapped at .035-.040 depending on power level.

I ran some TR8's earlier this year but just switched to a Delco, gapped at .025.

 

Update, I swapped out my TR6s for TR55s after just 2000 miles. I got stuck in a traffic jam and after that the engine developed a slightly rough idle. I would feel the engine do a slight "bump" when idling that I figure was due to the colder TR6 plugs having gotten slightly fouled from the traffic jam.

So the TR55s cured the rough idle for me. I'll stick with them from now on.

 

I see this is an old thread, but I'll post results

I've been using tr55s with heads/cam/100 shot for a little while now. I have not been able to see any signs of KR with some testing and the plugs look good even after several inspections after some good N2O pulls. They have been working ok so far. My car has been plagued with running overly rich problems so the plugs tend to foul up a bit, and I've been afraid that a colder plug will worsen the problem. I may change to tr6 anyway though, just for that extra bit of safety with the juice.

 

I'm about to switch to these because im in the process of adding a dry kit. with a full bolt-on stock motor LS1 am i going to lose much N/A with the colder plugs???

 

TR-6s gapped at .038 on heads/cam/nitrous Z28. No probls so far and 576/590 with a 100shot...