tr55 plugs

**blackbird99** · 02-26-2008, 08:34 AM

what kind of milage do you get out of the ngk tr55 plugs,the guy at the parts store said that ill have to change them out every 15 to 20000 then after that theyll run like crap.

**LS16SPD** · 02-26-2008, 10:19 AM

I Tried A Set And They Only Made It 2 Days Before I Took Them Out And Put The Delco Irridiums Back In!!! I Burned Them All To Hell!

**blackbird99** · 02-26-2008, 10:25 AM

i just talked to a guy at a local speed shop and told me to use the tr6 plugs.

**Firebirdjones** · 02-26-2008, 12:40 PM

I don't care for the NGK's after some things we found on a dyno session recently.

The guy at your local shop is recommending the TR6 plug because it's supposed to be a colder plug than the TR55.
For some reason,,,NGK raises there part number for a cooler temperature,,,

Japanese always doing shit backwards...

.......but those things still increased cylinder temps on the dyno over the stock ACDelco plugs,,,which are a hot plug anyway.

And since you can't tell how hot the AC plugs are for the LS1 (because it's no longer listed in the new part numbers) (thanks AC delco

) I decided to go with a plug that actually lists a heat range.

Crossing over the ACdelco part number gave me an equivilent heat range in Autolite,,,which was a #4......so we jumped down to a cooler #3 (number corresponds correctly with temperature,,,made in america

)

And the cylinder temps dropped slightly with these autolites in place,,,something the NGK's didn't do. Just food for thought,,,,,

**blackbird99** · 02-26-2008, 12:45 PM

so the autolites 103 should be cooler?

**Firebirdjones** · 02-26-2008, 12:50 PM

Hold on a minute and I'll get the exact number.....

**Mr. Luos** · 02-26-2008, 12:51 PM

TR55's will go 15-20K miles.

I run TR6's with a big cam, 402, and 11:1 compression. I replace them once every two years or so. 7-8K miles.

I don't care for the iradium's....4 times the price and last 3 times as long.

**Firebirdjones** · 02-26-2008, 12:58 PM

Okay,,,,Autolite APP103

This plug is 1 heat range cooler than the stock ACDelco plugs.
If you want an Autolite that is the same heat range as ACDelco then you would want the APP104,,,,but if you're doing that I would just go with the AC's anyway.
The reason I just went with Autolite is because they give you a heat range number to work with that actually works, and I wanted a colder plug,,,ACDelco doesn't on the LS1.....and the NGK's ran hot cylinder temps on the dyno no matter which heat range we installed,,,,,just seemed to be a very hot running plug.