battery cut off switch
You need to read the rules. The cut off MUST either be "twist to the left" for off or PUSH for off, NOT PULL It MUST be in the battery HOT lead, and it MUST kill the engine and fuel pumps. If you rig it to kill ALL power that much the better.
For unexplainable reasons you can download the much guarded NHRA rules from the Bremerton Raceway site fer free:
www.bremertonraceway.com/2011 NHRA Rulebook.pdf
IT IS IMPORTANT to realize that if all you do is cut the battery lead, the alternator will continue to run the engine. THIS DOES NOT satisfy the rules.
One way to do this is to buy a Cole Hearse 4 terminal switch, known as a "2 pole" or "double pole" switch.
It has 2 large heavy current terminals and 2 small "control" terminals.
Hook your switch in the hot battery lead using the 2 large terminals, ground one of the small terminals, and run an extra no16 or 14 wire up front, hooked to the remaining small terminal of the battery switch.
Buy yourself a good quality "Bosch" relay with a mounting tab so you can mount it somewhere.
Run "switched ignition" to one of the coil leads of the relay (85), and run your disconnect switch wire to the other coil connection (86).
Run a fused (10A plenty) hot lead to one contact (30), and hook the other contact to the field of your alternator IF YOU ARE USING a 70/ later alternator/ regulator setup (87). (NOT 87A)
If not, you can run the second contact to the IGN terminal of your regulator (69/ earlier) OR even use that contact to supply the ignition system. This works well if you are using a "one wire" alternator, but if you use the relay to power the ignition, you probably want heavier wire and a larger fuse
or if you want overkill, use a "constant duty" solenoid
IN OTHER WORDS the disconnect breaks BOTH the battery hot lead, AND it breaks the IGN supply to the alternator to cut the alternator
The point is, when someone operates the disconnect, it WILL kill the engine, pump, everything.
You need to read the rules. The cut off MUST either be "twist to the left" for off or PUSH for off, NOT PULL It MUST be in the battery HOT lead, and it MUST kill the engine and fuel pumps. If you rig it to kill ALL power that much the better.
For unexplainable reasons you can download the much guarded NHRA rules from the Bremerton Raceway site fer free:
www.bremertonraceway.com/2011 NHRA Rulebook.pdf
IT IS IMPORTANT to realize that if all you do is cut the battery lead, the alternator will continue to run the engine. THIS DOES NOT satisfy the rules.
One way to do this is to buy a Cole Hearse 4 terminal switch, known as a "2 pole" or "double pole" switch.
It has 2 large heavy current terminals and 2 small "control" terminals.
Hook your switch in the hot battery lead using the 2 large terminals, ground one of the small terminals, and run an extra no16 or 14 wire up front, hooked to the remaining small terminal of the battery switch.
Buy yourself a good quality "Bosch" relay with a mounting tab so you can mount it somewhere.
Run "switched ignition" to one of the coil leads of the relay (85), and run your disconnect switch wire to the other coil connection (86).
Run a fused (10A plenty) hot lead to one contact (30), and hook the other contact to the field of your alternator IF YOU ARE USING a 70/ later alternator/ regulator setup (87). (NOT 87A)
If not, you can run the second contact to the IGN terminal of your regulator (69/ earlier) OR even use that contact to supply the ignition system. This works well if you are using a "one wire" alternator, but if you use the relay to power the ignition, you probably want heavier wire and a larger fuse
or if you want overkill, use a "constant duty" solenoid
IN OTHER WORDS the disconnect breaks BOTH the battery hot lead, AND it breaks the IGN supply to the alternator to cut the alternator
The point is, when someone operates the disconnect, it WILL kill the engine, pump, everything.
