Should I consider a colder plug/change of gap?
Thread Starter
Joined: Aug 2005
Posts: 2,810
Likes: 3
From: Rock Hill, SC
Should I consider a colder plug/change of gap? I am running TR55s with my setup. I see that a lot of people that have bumped up their compression have gone to a colder plug and/or changed the gap. I was running the TR55s at the stock gap (.050), and yesterday I changed the gap to .040 and the car seems noticeably better. My compression is right around 11:1, could be slightly higher. I was thinking of taking the plugs back out and trying .035 gap. Should I make a change on the plugs I am running?
^what he said. if you do want colder plugs than the tr55s heres a list of some
AC Delco R42LTS
Accel 514
Autolite 104
Bosch HR8DPX
Champion RS9YC
Motorcraft AGRF42
Nippondenso T20EPR-U
NGK BPR6EFS
not quite sure if you should close the gap, but heres a little rule of thumb, if im wrong someone chime in
for every 50 hp added on a v8, reduce the gap .004" but if you have a better ignition system (idk if you do fergy, you have too many posts on the other site for me to bother looking lol) then you can add .002-.005 gap.
stock #'s for an lt1 is around 260...you have 385
...so thats 125 so reduce your gap by .011...which your right around with that .40 gap which explains why it feels better.
if your not really experiencing misfires or weak power then dont bother. too little of a gap=detonation and friends.
hope that helps fergy!
if your going to up the compression, go colder
AC Delco R42LTS
Accel 514
Autolite 104
Bosch HR8DPX
Champion RS9YC
Motorcraft AGRF42
Nippondenso T20EPR-U
NGK BPR6EFS
not quite sure if you should close the gap, but heres a little rule of thumb, if im wrong someone chime in
for every 50 hp added on a v8, reduce the gap .004" but if you have a better ignition system (idk if you do fergy, you have too many posts on the other site for me to bother looking lol) then you can add .002-.005 gap.
stock #'s for an lt1 is around 260...you have 385
...so thats 125 so reduce your gap by .011...which your right around with that .40 gap which explains why it feels better.if your not really experiencing misfires or weak power then dont bother. too little of a gap=detonation and friends.
hope that helps fergy!
if your going to up the compression, go colder
Thread Starter
Joined: Aug 2005
Posts: 2,810
Likes: 3
From: Rock Hill, SC
Thanks for the input. The car definitely had a high RPM miss before, it would stutter before shifts (at 6300). It still has it with the .040 but much more faintly. I should probably be running a little cooler plug...
I have run 104s and TR55s, in my car the 104s seem better from the drivability standpoint, think the smallest gap I have tried is .045 stock ignition.
11.5:1 and similar power though a lot less cam.
TR6 is a little colder worth a shot if you like NGK, I went Autolite because they are as easy to find as a Walmart.
11.5:1 and similar power though a lot less cam.
TR6 is a little colder worth a shot if you like NGK, I went Autolite because they are as easy to find as a Walmart.
