Airbox is front passenger, MSD one is middle driver side.

The MSD is driving the stock coil right now. Was going to put the high voltage MSD coil on, but wanted to do a plug check first. Glad I did. I was getting 1/3/5 misfire codes, but they have not come back since i reset the DTC's 200 miles ago. Both plugs were at 45 gap, I left them there.

I pulled them after 10 minutes of idle/off-idle low speed driving (went up and down the street). Pulled them out hot. AL 3923's.

I should add that I'm at 32 degrees of timing via SCT, and I'm on 93 pump gas.


20130910_134327.jpg

20130910_134334.jpg

20130910_135236.jpg

20130910_135247.jpg

20130910_135306.jpg

 

if it was mine i would put 3921 in.

 

How many miles are on the plugs?

They look very good. Just a bit of electrode wear. The grey coating is normal.

 

Not sure when I put them in. I'd say 2 years at absolute most. I thought they looked too white, myself. But if they're good, then I'll throw the big coil in it. I think I put them in at 40 or 45 (I know I went wide for the methanol), so either they've opened 5 or none.

 

I sent the pictures to Hemifever, he thinks it's hard to tell if it's range-hot or not, but thinks it may be, and I kinda think it is. would 3921's be too much of a drop? -> 3922's

 

It's hard to tell from the pics. I don't think you're off by much on the heat range. Try either the 22 or 21 and see what happens.

 

In searching, the consensus is to go 1 heat range cooler on MSD. Reason being, the multiple spark duration per MSD is 20 degrees, at 520-535 volts @ 135 milliJoules. Thus, the plug stays hotter than a standard single spark, and running a hot plug that way just makes a hotter combustion chamber. I'm at 32 degrees of timing per the SCT tune, so it's sparking from 32 BTDC to 12 BTDC.

 

got the HVC coil put on. See if it throws any misfire codes tomorrow, if so, I'll pick up some 22's, else, I'll keep the 23's. Seems to be a good bit of life left in them.