I am wiring up a nitrous system in my car and have a seemingly (to me) simple question.

Is there anyway to kill power to the nitrous relay via the clutch switch?

Basically the system will be wired as usual, but when I stab the clutch to shift it kills the system and once released (the clutch) the system reactivates.

I know a RPM window switch would be the smarter way to go as my old system was wired this way, but I am out of spare cash and want to get some TnT in next sunday. Am I nuts for thinking of such an idea, or can this be done?

No you're not nuts :)

Yes, entirely possible. I'm assuming you've got a 1969 or later? '69 was the first year for the "clutch safety switch", in other words GM did not want you attempting to start the engine without pressing on the clutch pedal, so they added a switch onto it (much like the neutral safety switch on an automatic).

Since when you press in, you actually complete a circuit, you'll have to get creative (yes kiddies, with relay(s) :D ) so you'll make something that in turn breaks a connection (to your NOS system).

I can design you something, but I need more info on how a (well yours) NOS system works. How much current does it pull when it's on? Is it on all the time? Do you want to kill the (+) side or the ground side of it?

No you're not nuts :)

Yes, entirely possible. I'm assuming you've got a 1969 or later? '69 was the first year for the "clutch safety switch", in other words GM did not want you attempting to start the engine without pressing on the clutch pedal, so they added a switch onto it (much like the neutral safety switch on an automatic).

Since when you press in, you actually complete a circuit, you'll have to get creative (yes kiddies, with relay(s) :D ) so you'll make something that in turn breaks a connection (to your NOS system).

I can design you something, but I need more info on how a (well yours) NOS system works. How much current does it pull when it's on? Is it on all the time? Do you want to kill the (+) side or the ground side of it?

Yeah it has the clutch switch....'82 here.

I have an activation switch (interior mounted) that acts as a master arming switch for the entire system. That is powered from an IGN hot at the fuse box to the toggle, then from toggle to underhood relay. Relay gets full 12V juice from a Junction Block getting juice right off the alternator BAT lug post. The accessory wire powers the solenoids when the relay is activated. The ground of the relay then runs to the carb mounted WOT switch and then the other post of the WOT switch grounds on the nearest carb stud. So I arm it with the toggle, but it still does not fire till the WOT switch closes, grounding the relay and firing the system.

Not sure about the current to be honest...probably 40 amps tops or so...only on when I activate it...but triggered by the WOT micro switch. Would like to kill the (+) side of the system....thinking of using another WOT switch...?

Theoretically I should be able to use a WOT switch in reverse on the toggle wire that provides the trigger to open the relay. Basically have it right against the clutch pedal, hence it would be a closed circuit. But with even a small amount of clutch pedal movement the switch and hence the entire circuit would open and kill the system with any clutch movement?

I am thinking about doing this for a starter interrupt. I will put mine on the bellhousing and use a micro switch with the ground for my starter relay running through it. When the fork moves away from the switch, the circuit is closed and the starter relay will get a ground and when the switch is activated by the fork compressing it, the ground circuit will be opened and the starter can't be activated. Do your Nos setup just the opposite. I did this on a mopar with NOS 15 years ago and it worked good.


HTH

just put a microswitch on the brake/clutch pedal mount under the dash that completes the circuit when the pedal is all the way out, and breaks the circuit as soon as you push it in. just run it inline with the WOT switch from the master arm switch.
simple.
by keeping everything inside the car, it's protected from the heat and elements of being under the hood.