you need at least zero guage wire. A lot of people try to do it with 4 guage wire but that is not sufficient. It will work but the started takes longer as if your battery is dead sometimes even when it has a good charge. My friends car had 4 guage running to the front and his battery seemed weak all the time and didn't take much to kill it completely and then he ran zero guage and it's been fine since then. I had dual 4 guage in my del sol and never had an issue.