okay, straight from the nhra rulebook::::8.4 MASTER CUTOFF "mandatory when battery is relocated or as outlined in class requirements. an electrical power cutoff switch (only one) must be installed on the rearmost part of each vehicle and be easily accessible from outside the car. this cutoff MUST be connected to the POSITIVE side of the battery and must stop ALL electrical functions including magneto ignition. the off position must be clearly marked with the word off. if switch is "push/pull type", PUSH must be the action for shutting off the electrical system, PULL to turn it on. any rods or cables used to activate the switch must be a minimum of 1/8" diameter. plastic or keyed switch prohibited. switches and/or controls must be located behind the rear wheels on rear engined dragsters."
electrical: 8 master cutoff switch required on any car running 9.99 (6.39 in the 1/8)or quicker, any car exceeding 135mph, or any car where the battery is relocated into the trunk area.
Ah $hit!!! I was wrong, I'll admit it. I forgot that the alt grounds itself and bypasses the battery so just interrupting the battery ground only helps if the engine isn't running. If you didn't have an alternator and were just running off the battery, you could put the switch in either side, but that won't make the NHRA happy. Oh well, at least it forced me to take a refresher course on charging systems.
The one that JEGS shipped was the 74101 which was described as "for cars with alternators" but it only has two large posts on the back. I got onto Moroso website and found that they have a 74102 (I didn't see that in the JEGS catalog, but found it online when I entered the number) which has 2 large posts for the battery and 2 small posts for the alternator. I guess I got the wrong one. Anyone know if I will have to pay shipping twice for a swap (equaling an extra $25 round trip)? If so, I might just get my money refunded and buy it through a local parts house and not pay the shipping.
ture lots of wiring .. however i would say that those would be better in race cars then a street car. my friend had one of those in his everyday car... ended up going back to an optima. maybe becuase it was a new car.. but a few pounds of weight over the tires (which i don't think anyone meantioned) works for me too! yeah but if you do that same thing and touche that wrench a conducting area on the car.... i'd really like to see that in person while standing next to you... when you jump for your life when a big spark comes out sorry dude.. your gonna get a spark when that batterys in the car. if you don't i'd say you have some grounding issues. exactly!
Don, on your two-posts, will the engine die when you kick the switch off? It would be nice to be able to used the one I have and not mess with the BS of returning and extra shipping.
Don, exactly HOW do you have it wired? I would be willing to go for a one-wire alternator (which I have wanted anyway, with more amps) before sending my current switch back.
There are two configurations. One is the alternator can still run the engine indepenent of the battery in some cases whether the battery is disconnected or not. We have this situation in the sprint car with the same type cutoff in the cock pit and an alternator in use. As another FYI, all modern fuel injected cars and truck have crash sensors to cut off the hi pressure fuel pump so it does not feed a fire in cases of an accident that would still leave the engine running and occupants in the vehichle. Usually when the engine stops the pump stops because of the way the pump control system is designed to be kept operated as long as the engine is running otherwise the pump stops when engine dies. Air bag systems have backup power in case the battery circuit opens from an accident. So there are many applications for this logic both ways.
Your switch you have now will work for both the stock alternator and a 1-wire. You just take the + wire from the back of the alternator (the one that goes to the starter selenoid), and run it all the way to the back of the car to the switch. Put it on the battery side of the switch on the same post, that way if you turn off the switch it will cut power from both the battery and alternator.
I can tell you this: If you have a master disconnect switch and connect it to the neg. side of the battery---if you have a short somewhere in any pos. wire, it can act as a ground and the master disconnect just became useless until that "shorted" wire burns itself in half. I've seen it myself-on MY Maverick. It's on the + side now!
OK, I will try that. Your description sounds like only one wire running back to the positive post of the switch, so in effect, I am using that switch as a replacement for the solenoid (for the alternator wire only), and no second wire would need to run back to the front, correct?
