novablue454

Hi everyone, I've been searching and doing some research, but I still can't decide what plugs to run. The engine is a LS6 from a 2004 CTS-V, and the only mods done to it (that I am aware of) are CXracing E46 swap headers, a catless exhaust, and a cold air intake. I am around Denver so 5280-6000 feet in elevation.

I put TR6 in for the initial start up, and they were OK for a few starts. Once I trailered the car to get an alignment however they all fouled and it wouldn't start. It was about 30 degrees out, and the O2 sensors hadn't yet been connected after the exhaust shop had it. I'm sure it was a combination of factors that caused them to foul.

I replaced them with TR5 and it seems ok. Starts right up, runs great.

I'm reading now that TR5 are the wrong gap and I actually should be using TR55 with this setup.

I have a tune set up for Saturday and the tuner hasn't yet answered my email about which plugs he recommends which leads me here. I wan't to change them again right before it goes on the dyno, but want to make sure I am using the correct plugs for my engine. mods, and elevation.

thanks!

thunderstruck507

iTrader: (18)

TR5 and TR55 are the same minus gap, it really doesn't matter. Just leave them unless you've been running around with no o2s again which can foul them out.

I've ran a gap of .035" to .060" with no difference. As long as you don't have too much gap it'll be fine.

novablue454

Nope, I connected the o2 sensors before we started it with the TR5 in, and have put maybe 5 miles on it since. Ill just leave the TR5 in for the tune but pick up a spare set to take with us in case they act weird.

Thanks!

IDriveChevy

iTrader: (5)

Tr6 are one heat range colder than tr5s, people like the 6s for nitrous.