I just got some NGK TR6 spark plugs....which is one heat range colder than stock and used in the 2002 Lightning. I know a lot of guys that are blown or spraying use the TR6 plugs, but should I be ok using 1 heat range colder as long as I gap them according to factory specs??

A little background: I'm experiencing a some very minor detonation due to my tune and I figured that I can try a colder plug to get rid of the problem instead of backing off the timing and possibly losing power. Any thoughts??

 

You can try but i dont think the colder plugs will fix your problem unless it just needs to be run a bit cooler. and you can gap them to stock specs and be just fine. the reason they come gapped at .035" is because they know they are used mostly for nitrous and blower applications.

 

The rule of thumb is to use the coldest possible plugs w/o getting fouling or drivability problems. One heat range colder should be fine. One of the reason why ford uses the heat range they use is for emissions, so watch it if you live in a tough area.

It might help your detonation problem.

 

You shouldnt be having problems with noticeable detonation. Sounds like you are running too much timing.

I remember when I first got the nitrous I needed plugs and I got autolite 103's. I tried the stock gap first. When I read the plugs with the stock gap they were always really white meaning its running too hot. Then when I went to .035" the car ran much smoother and the plugs were back to normal color.

Then I switched to NGK TR6 gapped at .035 and the car seemed to run better than with the Autolites. I know that the NGK's are One and a half steps colder than stock. Autolite 103s are only one step colder.

If I were you I wouldnt just use a cooler plug unless your just doing this for temporary. U should find out whats causing the detonation and fix that problem because you will just complicate things by using different plugs.

 

TR6's are only one step colder not 1 & 1/2.

 

I agree, it sounds like you're running too much timing or not enough fuel. A drop in plug heat range should ONLY be a temporary fix for this. Back off the timing and/or get it dyno'd to check the A/F ratio before you call the problem fixed.

 

It's kind of weird cause the very minor detonation I'm experiencing happens right at about 2,100rpms.....and I notice it if I hold it there, but if I blow right past it, no detonation. I looked at my dyno graph and the A/F is about 14.5 at 2,100rpms and then goes down to gradually and at about 3,000rpms it gets to 12.5 all the way up to 6,700rpms or so. So I'm running to lean at 2,100rpms. I'm probably going to replace the plugs anyway and then take it back to the tuner and see what he can do. Hell, he might even be able to run more timing with the colder plug.

MT's#1Customer.....thanks for the info about the plugs not being emissions friendly. I live in the SF Bay Area, which probably has some of the toughest emissions laws in the nation so when it comes time for the emission test I'll have to do some work to get the car back to pretty much stock. :helpsmili

 

your tune is bad

 

Yup, needs more fuel in that area if your A/F ratio is that lean and then goes richer at higher RPMs.