Steel City said:
You probably can get away without a tune with just a 3.1 but why change the pulley for just a 3.1 and why chance it???? Get a 2.90 or 2.93, great bump in power. Stay away from the predator unless that is your only option. Im not saying the predator is bad but it is not near perfect. You seem to be a little on the concervative side and if you have concerns just get a real tune. As far as the ngk's being an issue I have never heard that one before except in incorrect applications, they are 1 step colder than the factory plugs. 3-4 psi is a very noticeable jump in power when tuned properly.
I have to agree here..
we currently run tr6 in every stang in our garage.
the densos will blow out UNLESS you upgrade your ignition.
They have a hotter spark, but not a BiGGER spark, they blow out easire than the stock plugs.{with a pulley increase}
Densos blew out on our lightning as well above 15 psi.
The tr6s are the perfrct plug for moderate boost.
they actually make a tr"9" {call ngk} if you are running REALLY HIGH BOOST, but warm ups take a while before you idle right.
On our 1996 Cobra:
stage 3 cams, 20 over, 8.5to1 comp,55lph inj,accel gen7,ati ps1c-r,no imrc,full port work.{498 @ the tire with only 8 lbs of boost}
When we were tuning, and went to 14 psi, we had densos in it, we thought something was wrong with the gen 7, turned out to just be the plugs.
TR6 are the 'Kiss Me''Kiss Me''Kiss Me''Kiss Me'nit.
MAbye u.m. had a problem with them becasue of plug length, some are 1" and some are .5", a shorter plug might have given him a problem...
Dont know for sure.
Tr6's are in all my cars though..
lin