View Full Version : ignition/plugs

09-22-2005, 09:46 PM
On the 01...finewire plugs have been suggested. Is there a difference in the finewire plugs from denso,ngk,champion,autolite? And what is this e3 plug? I appear to get a misfire at high r's and sometime at low r's. Any suggestions? The car is not too far from stock.

john in va beach:D

09-25-2005, 10:31 AM
just about all of the plugs you mentioned do not have a fine wire except the tip may be reduced in size. The only fine wire plug I have seen are the Bosch platinum +4's which should not find their way into a cobra let alone any mustang. However, all of the plugs should be classified as resistor plugs since the coils sit on top of the plug which aids in reducing energy spikes in the dc supply line to the ECU as well as the radio. The best type of plug will only have a single ground prong which provides a better flame kernal. The e3 plug has a larger ground surface area which may cause pre-mature failure (more likely to get contaminated with carbon deposits). The cheapest plug which many rave about are the autolight 763 copper plugs. Platinum and irridium plugs use a smaller electrode since the metals will not erode at high temperatures when compared to copper. Copper (500 C) has a lower melting point than platinum (1800 C) or irridium (2400 C). It is the arc temperature that will erode the electrode not the combustion of the fuel. The best plug design has a slightly rounded ground prong and sits slightly off center to the electrode. Just in their design, the e3 plug does not look like a good candidate for use in a high compression motor, especially if you are running with power adders like supercharger, turbo or NOS.

Misfires may be caused by the sparg gap being too large or too small. If the gap is too large it will miss at higher RPM's. Too small of a gap will lower the voltage potential of the spark and make it weak. Some plug designs favor a larger gap and some work better with a smaller gap. When looking at the e3 plug design, it cannot be gapped if it is the one with the large ground with the diamond cut hole in the center of it.

09-27-2005, 11:22 AM
So ausie which plugs would you go with on the 99, 01 cobra??

09-28-2005, 06:18 AM
If I still had my 01, there would be denso irridiums in the mill. That was the first car I ever put them in. I have tried other plugs including the 764's which I tried after installing the denso's and I could tell the difference, the car was sluggish with the 764's when compared to the denso irridium plugs. I had other issues that warrantied the need to try other plugs. The 01 had the "ping" issue and I found that the denso irridium plugs reduced the pinging to almost nil (depending on who's gas I used in it).

Since I liked the denso's in the 01, I put them in my 04 ( a different heat range of course) and the result was very much the same, improved throttle response. It is alot of money to part with especially for spark plugs, but for my vehicles it was worth it. I have not really noticed any improvement in gas milage (probably because the gas pedal is stuck to the floor more than I like it to be) but there is a difference that you can actually notice in a stock mill running the stock code (N/A or supercharged). It there was a better plug out there that cost less I am sure I would at least try it once (maybe).