4AGZE Supercharger clutch, relay through ignition?

Yet again I accidentally left my supercharger on and drained the battery flat.
 
It has an aftermarket switch wired directly from the magnetic clutch to the battery. I was wondering if the factory setup ran via a relay triggered by the ignition?
 
I am considering using a generic relay, so the charger will turn off with the car, my only concern is reliability, if the relay were to fail while cornering it could be fatal... has anyone else done this and what is their experience? 

Why not just change it back to the factory wiring setup.

Do you know if it is a factory pulley on the supercharger?? Some of the other pulleys that get fitted to the supercharger for higher boost (ie the pulleybros kit) run a relay triggered by the factory wires, but run a higher current wire to the to the clutch assembly so it doesn't slip. It could be possible this has been setup with a switch to stop the supercharger from engaging, however that wouldnt cause the battery to go flat if left on.

if the s/c engages like normal from the ECU disconnect the switch wired in and throw it in the bin. 
it's all BS claiming to get better fuel economy etc. by manualy having the s/c switched off.  warming engine up?
the s/c is only going to come on if you give it enough throttle, same with driving around town and on the hi way. 
 
your right foot controls your fuel economy wether the s/c is on or off.  buy a vacuum/boost guage and drive it via that if you want to be real anal about fuel economy.  the s/c aw isn't that bad on fuel anyways.

Not sure I agree with removing the switch entirely: It has bugger all torque below 3.5k, very slow and lethargic as I would expect from a lower compression 4A. This is just not practical in heavy traffic (or cruising with others).
 
It uses twice as much fuel with the S/C on: On a recent club run, I literally avoided running out of fuel by switching it off, otherwise I would have inconvenienced 8 other drivers by making an early stop, or be forced to abandon the run (how can I keep up without accelerating... seriously?).
 
I am currently on a tight budget, if I remove the switch then that forces me to drive in lethargic torqueless mode 80% of the time. If I must completely alter my driving style and not enjoy the car, then why not just own a crap N/A FWD hatchback, or ride a bicycle instead? I love driving a mild, economic daily which I can switch into an animal on the weekend, this flexibility gives me the best of both worlds, I don't understand why that is a bad thing?
 
No offence, I do respect your opinion and really appreciate the feedback, I just can't see the logic as it applies to my situation?
 
 
 
 
 
 
 
 
 
 

If you're using that much fuel, sounds like there is a whole lot more wrong with your car than just the supercharger switching in.
 
When did it last get a proper service?  Plugs, leads, air filter etc.  Also, what fuel are you using?  The extra cost of premium grade is more than offset by the extra distance you'll get on each tank full.  PM me if you'd like to chat further, I'm sure you'd want to enjoy your little gem properly . . .

Thank you all for the input.

I only use BP ultimate, I would use 100ron if it was easily available here.

It had a major service 2 years ago by the former (mechanic) owner. Yes it is overfuelling with the charger on, and also has a flat spot, she could do with a tune up. The only local shop I could find with the equipment to run a diagnostic on it is an expensive race builder I can't afford right now. She is due for her 200k service, I intend to replace:

Timing belt, water pump, a/c-alt and s/c belts, plugs, leads, pod filter, all fluids. It also needs a new cat and muffler. I was considering doing the head-gasket (+bolts), cam seals etc, but will probably just leave it for now.

It sounds like the temp sensor could be an issue, when it's hot, it often drops the idle speed too low and wants to stall. It is not overheating, did 700km on very hot day without issue. Other than this, and the slight flat spot around 3.5k, it runs beautifully.

It gets around 250-550km per tank depending on conditions, the charger and driving style.

Feral- please do not mistake humility for inexperience. I have owned many cars, including two N/A Aw11's, I have driven professionally for some years. I can and do drive the 4agze off boost, however you seem to be missing the point, which is that I actually LIKE the alternative, mild behaviour of this car for commuting and extended highway cruising, economy aside, it is smoother and sounds nicer. Each to their own.

Head to opc.mr2oc.com and download the BGB, usually the '89 one is pretty good.
 
Read up how to put the car in diagnostic mode (involves bridging two connectors on the diag plug in your engine bay), then you will get blinking lights for any sensor fault codes, that's a good place to start.
 
It's pretty easy to explain it here, but I recommend you read the BGB because you will find it's actually pretty easy to give these cars a bit of mechanical love that only an owner can. You can always find a good mechanic but you are paying them for their time to look at the car, whereas you can do it anytime you want and give it good attention to detail. You don't need any fancy diagnostic gear because these cars are pre OBDII etc. so the diag mode is as good as any piece of hardware! The ECU certainly doesn't have any learning when it comes to sensors, no limp home mode etc.
 
If you don't have any sensor issues, then continuing reading to learn how to check things like your TPS, vacuum system etc. so everything is in spec. You'll find a lot to gain about fine tuning the car so it runs as healthily as it can without actually having to replace anything (if diag mode comes up clear that is).
 
For extended highway cruising, the SC is usually switched off anyway, so you aren't silly for liking it. All we are saying is under normal conditions, you shouldn't need to worry about a switch to turn it on during cruising; it'll only ever engage when you put your foot down for overtaking etc.
 
I love sitting my GZE Auto on overdrive so it sits at 2,200rpm doing 110kph down the highway, no SC engaged, such a nice and quiet cruiser (except for wind noise of course).