Question about a/c WOT switch and nitrous

[mob]

Hey guys, I have a 93 mustang. So the relay next to the fuel pump relay is supposed to be an a/c wot cut off switch right? What measures the wot on our cars? The tps? In planning on hooking up my nitrous kit why cant I just wire nitrous to turn on through that relay instead of mounting a little switch to the throttle body?

 

[Blown88GT]

The Clutch Cycling Pressure Switch is in series with the WOT relay. You would have no nitrous whenever the A/C compressor clutch is shut off by this switch.

 

[jrichker]

Use a Single Pole, Double Throw relay with the coil wired to the WOT relay and ground. Use the relay contacts that are not closed when the relay has coil current. That way when the A/C WOT relay opens up, the other relay does too, and the contacts close and make a path for the electricity to open the nitrous solenoid.

 

[mob]

Awesome Joe, that's exactly what I was thinking, I would just wire it up to another relay, for some reason I see everyone mounting those little micro switches to the throttle body, this seems a lot easier.

 

[Boydster]

My only question would be: when does the ECU consider the throttle in WOT? Anything above 3/4? 5/8? 7/8? Only true 100%? Seems to me you'd want to find out at what voltage from the TPS does the ECU consider WOT, and make sure the TPS is set correctly.

This is where the switch on the throttle seems easier... pretty easy to just look at it and rig it for WOT.

 

[jrichker]

My only question would be: when does the ECU consider the throttle in WOT? Anything above 3/4? 5/8? 7/8? Only true 100%? Seems to me you'd want to find out at what voltage from the TPS does the ECU consider WOT, and make sure the TPS is set correctly.

This is where the switch on the throttle seems easier... pretty easy to just look at it and rig it for WOT.

All it takes to find out is to use a voltmeter and measure the voltage across the A/C compressor clutch coil and open the throttle. I don't think you would even have to have the engine running, just turn on the ignition and A/C and measure away.

 

[Rick 91GT]

Ive wired it into the clutch pedal as well so when I pushed the clutch it stopped spraying for that micro second

 

[Boydster]

All it takes to find out is to use a voltmeter and measure the voltage across the A/C compressor clutch coil and open the throttle. I don't think you would even have to have the engine running, just turn on the ignition and A/C and measure away.

Exactly... and this should be suggested to anyone wanting to spray off that relay.

 

[jrichker]

Ive wired it into the clutch pedal as well so when I pushed the clutch it stopped spraying for that micro second

Excellent idea, and one that I would recommend as well.