A/C

[84E24]

I am re-working the air conditioning with a modern unit.

Is there anything built in or something i could add to increase the RPM when the AC is on. At idle and the air on the RPM's drop to almost stalling.

Also, my Blower Unit needs replaced. Anyone use an after market unit like Spal Electric fans?

Thanks,

 

[jmackro]

Regarding the idle speed: is your car carbureted? If so, the usual fix is just to increase the idle speed so it's too fast with the A/C off, but OK with it on. I can imagine some fancy solenoid throttle stop that kicks in with the compressor clutch, but I'm just conjecturing here. On an injected car there may a more sophisticated solution involving the idle air control valve.

Regarding the blower - your problem is the volume in the console. The stock set-up probably moves as much airflow through such a small space as possible. Modern cars have bigger units, plus ducting to distribute the cool air. So, my guess would be that to get more airflow you would need to make some drastic modifications to your dash.

Let me ask you a couple of questions:
What sort of a compressor will you be using? Something from a later BMW, or just a generic rotary? How will you handle the bracket?

 

[sfdon]

If your car is fuel injected- you need part # 2 and the correct hose....

http://www.realoem.com/bmw/showparts.do?model=3995&mospid=47163&btnr=13_0199&hg=13&fg=05

 

[84E24]

The car is a 73 cs and has twin webbers. I agree that the only way is to increase the idle or just keep your foot in it.

The fan is item #1. Does anyone know where the Temp Switch # 17 -18 is located?

http://www.bmwmobiletradition-onlin...el=7013&mospid=47811&btnr=64_0882&hg=64&fg=55

I purchased a kit from Max at Maximillian ( 800 950 2002 ) it came with a mounting bracket. Over all pretty easy convert. Had to make new hoses and relocated the service ports a little higher. as I am going through the system found out the the temp switch at the console was bad and the fan in front of the rad. was also bad.

Thanks,

 

[gwittman]

I did exactly what you want with very little modification. My car has a vacuum diaphragm mechanism (at the rear of the throttle linkage) that is activated electrically when the engine is above a certain rpm to keep the throttle partially open during deceleration (emissions related?). I decided I could use that system to increase idle rpm when the A/C was on.

I don't remember exactly how I did it but as I recall I added a relay near the A/C relay and connected it so that when the A/C clutch kicks in the vacuum diaphragm would also be activated to raise the rpm. I adjusted the screw on the vacuum diaphragm to hold a good idle with the A/C on. Works great. My A/C needs a recharge now so I am not currently using it.

 

[KHB]

If you are still in need of an electric radiator fan, consider the older SAAB 900's as a source. I used the one out of my '87. The 900 has two different fans, but one of them has the same motor housing and fan style as the CS you just have to remove the plastic SAAB bracket and mount it to the CS bracket.

The fan diameter is slightly larger though and the blade will hit the front edge of the hood when open. I used spacers (about 3/8") to mount the motor bracket below the support brackets to resolve this. Or you could relocate the support brackets, but I don't like adding holes to the coupe. On the plus side, it will move more air. The connector plug of course is different, but that is easy enough to overcome.