My car still had original wires on them. I know this because cosmoline flakes were all over them.
I had never attempted to gather raw data from any mods I had done over the years. This time around I was inspired to try with the COP conversion because of a Grassroots Motorsports magazine article where they showed an 8HP increase just by replacing the spark plug wires. Granted, they were just getting HP they should have already had, I still wanted to see what would happen if I tried to gather data.
I used an Ipod touch with dynolicious software. 4 runs with the tired old stock wires and 4 runs with the COP conversion.*
Averaging out the runs, I found a 9HP** increase! 66.7 to 76. WOOHA!
So if you haven't done it by now, go do that COP conversion!
* Professional driver. Closed course.
**Results may vary.