V8er

iTrader: (2)

The old spark plug rule of thumb was one heat range colder for every 60 additional HP. A strong H/C 346ci LSX engine makes around 450rwhp which is close to 200HP more than a stock LS1. Why wouldn't we want to use the TR6 plugs in place of the standard heat range TR55 version? What possible disadvantage(s) would the colder plugs have? The colder plugs should help to pull more heat from the combustion chamber.

brad8266

iTrader: (23)

Run the TR6 with that setup, **** I ran them on my DD 346 with no fouling or idle issues.

TORCHD 02 TA

iTrader: (39)

Its a colder heat range plug than the TR55, but not due to a smaller gap. The physical design of the plug is what determines how much heat is dissipatates not the gap.

98Camarod

iTrader: (43)

I run TR6's too for the occasional nitrous shot, my mods are in my sig.

V8er

iTrader: (2)

I understand that and I wasn't ever discussing the gap size, just the heat range of the TR55 vs the TR6.

Unless the car is driven at light loads in artic temps why not use the TR6 in 400rwhp+ cars?

The reason I asked this question is because all I ever see being suggested on this board is the TR55 and never the TR6 unless it is a NOS car.

brad8266

iTrader: (23)

sounds familiar.

98Camarod

iTrader: (43)

Actually I am a liar, I changed the TR6's out and put in Autolite 103's same heat range though. The only difference is you can buy these at walmart.

brad8266

iTrader: (23)

Some people here just think that the rule in stone is if you spray then TR6 and if you are NA then TR55.

You got it right man, with the added power you want a colder plug since the increase in cylinder pressure will generate more heat which needs to go somewhere. The colder plug will get rid of that extra heat.

c5_ls1_6spd

iTrader: (-1)

Im making over 450 and using TR55s also. No problems here with fouling or sputtering, etc.

brad8266

iTrader: (23)

Thats because you are using 55's, the TR6's are known for fouling in stock/mildy modded applications, although it never happened to me.

V8er

iTrader: (2)

By this same logic a 1.75" exhaust should be fine if you are making 450rwhp with it on the car

No doubt your TR55s are working but would TR6s be better?

brad8266

iTrader: (23)

c5_ls1_6spd

iTrader: (-1)

why would TR6s be better?

brad8266

iTrader: (23)

Because 55's get too hot with the increased cylinder pressures that come from high HP. Once they become hot enough they can preignite the fuel.

TORCHD 02 TA

iTrader: (39)

was waiting to see if ya caught that

V8er

iTrader: (2)

I am going to install a set of TR6s and report back on how they perform.

TheLS1Kid

iTrader: (12)

I have a H/C 346ci LS1 and i use TR6 plugs gapped at .035. Runs great.