Stand Alone ECU and A/C control

[NoClassic]

Im in the process of an LS1 swap in my 89 S13, and have just begun to get into the wiring.

I will be using the GM ECU and harness for engine control, which will remain separate from the chassis wiring save for power and ground. Pretty much like a stand alone.

Alot of people who have done the LS1 in Mazda F chassis cars retain the mazda AC control system. I would like to do the same with my car if possible.

I am not worried about idle speed bump, or high RPM clutch deactivation. The LS1 has plenty of idle torque to handle the compressor load and Im hoping I can remember to manually deactivate the system if I plan on seeing high RPM.

My question to you guys is will the Nissan AC control function remain active if I remove the OEM ecu from the system. If I can do this I plan on running a direct lead from the AC button to the appropriate relay in the AC control circuit.

I know that a majority of the system is managed by mechanical pressure and temp switches. However there are a few leads that make their way back to the ECU. I think these may be for idle speed increase with clutch activation, but im not %100 sure.

Let me know if any of this is wrong or have any insight in aid of the situation.

[boostin13b]

Your right, the main control of the system is through the pressure switch itself. The only thing you have to worry about is wiring a signal wire into your stand alone to let it know that your a/c is on to idle it up which most good quality stand alones will have that function, and turning on your condensor fan when the a/c is on. Most people just wire their fan to ACC on so that may not be a problem. The a/c system on 240's is pretty simple for the most part.

You won't have to worry about the temp inputs, it would be pretty difficult to wire those in properly, if all your a/c components are in good working order, the pressure switch should be sufficient to run the a/c system. Most SR swaps are run directly through the pressure switch.

[NoClassic]

Thanks for the confirmation.

Any chance anyone has a diagram of how people wire AC in the SR swap.

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[boostin13b]

do a quick search, I know I've seen a few on here.

[Z U L8R]

quick and easy....on the dash plug behind the glove box is a blue/green stripe wire, run that to your brownish red plug by your stock battery location. connect that to the green/yellow stripe. when you request ac, your compressor will get 12v via the ac relay.

essentially you're giving the ac relay the ground from the ac request button when the blower's on. in turn the ac relay will send your compressor clutch power via the blue/red stripe wire from the fuse block where the stock ka's air filter is.

run the blue/red stripe wire to your compressor and enjoy

gl man, post some pics when you're done with yours. we're doing an ls1 in an s14 at our shop atm :)

ya gotta love 400hp all day every day with 25+ mpg, cold ac and enough torque to shut ur complaining girlfriend up hahaha

take care
Dave @ Lethal Injection Motorsports

[RACETUNE]

Answer:
everything will still work fine. the wire from the a/c clutch switch to the nissan ecu needs to go new ecu for the input for the Idle up when ac is engaged.