Cutting back the ground electrode is nothing new. I used to cut back the ground strap halfway in high school in the early 70s. And it was being done by others way before that. The reason for doing it back then was different in my case. Electricity will jump from a sharp edge easier than it will from a rounded edge. Less chance of misfire. It was one of my little tuning procedures I used that made that little 307 SBC surprise a lot of people. Back to the present. I started out by cutting back the ground strap halfway with the Alky V6s. Cutting back a ground strap halfway means having to end of the strap extend halfway over the center electrode. With version 2.0 I did notice some heat discoloring of the ground strap end (1/8 inch), but I didn't feel it was something to worry about. Version 2 was the engine I started using nitrous injection to quickly spool the turbo. I use a 200 HP shot (jet size), but when using alcohol, the actual HP level increase is more like 140-160. Before using nitrous for turbo spooling, I had only read about it in books. It made good sense to me and I always wondered why it wasn't done more than it is. I have to tell you after doing it, it is the cat's meow. :wink: At a later point in the testing of Ver. 2 I decided to try injecting the nitrous for the complete run. When I look back on it and think of the tuneup configuration (mainly the equipment, not the engine software) I was using at the time, it was a foolish move. For one thing the wastegate was way too small to handle the extra exhaust energy that would be present for the whole run. I have since installed a 60mm wategate, but I would also install a turbine housing with a larger a/r and 2 steps colder spark plugs. I did make the run and man was it pulling.
Shortly after shifting to 2nd, there was a loud intake backfire (pop)
and I got out of it. The wastegate could not handle the extra exhaust volume and the engine overboosted. The engine came out of it OK, except for the spark plugs. Two were missing all or part of the porcelain and the rest had the ends of the ground electrodes partially melted back into a ball. I think I still have one. I'll try to remember to post a pic of it. A leakdown test confirmed the engine was OK. I noticed how far back the electrode melted and that is the point where I now cut back the electrode to.
Shattered porcelain is a sure sign of preignition. I was lucky on that run. I have since only used the nitrous to spool the turbo.
I am using a regular nose plug (non-projected tip). It has a shorter ground strap and when cut back, it is really short. The shorter the better.
One plug type I keep wondering about is the retracted gap or surface discharge. Does anyone have any experience using these plugs?