Ideas Needed for Raising Idle Speed for Aircon

[Davo]

I've just put an all-new aircon system in the Rangie, (with carburettors), and have found that, even though the factory just set the idle to 800rpm to compensate for when the compressor kicks in and drags the idle speed down, it doesn't really work. You wind up with either an engine idling too fast, or pulled down a bit too slow. I've done a big search for an "idle solenoid" or whatever else it's called and can't find anything that sounds like it actually works. Is there some other ingenious way of doing this which someone else has come up with so I don't reinvent it? (And no, the answer is not: "Fit Megasquirt"!) 

[Cynic-al]

Get a 12v solenoid and mount it to push the idle stop at the carb then wire it to the ac compressor clutch so that the 2 come on together?

 

If you need the idle solenoid to come on before the ac compressor you can get delay timers.

[Bowie69]

The way I do it with Megasquirted engines, is advance the timing a touch at that point in the rev range -you could fit something to the dizzy to do similar, again with a solenoid affair as above?

[Davo]

Ta very much. I dare say this will take some pondering. This: http://www.ebay.com.au/itm/HOLDEN-RODEO-88-98-4ZE1-ENGINE-FAST-IDLE-SOLENOID-NOS-GENUINE-8941469092-/181130402370?hash=item2a2c369a42:g:RSUAAMXQHO9RezYW looks good, though I can't see how it attaches or anything. It seems that just a plain solenoid doesn't have the strength and needs vacuum assistance, like this one. 

This: http://www.ebay.com.au/itm/Electronic-Pull-Push-20N-DC-12V-10mm-Electric-Release-Solenoid-Latch-Lock-Tool-M-/152234083361?hash=item2371dbc421:g:mfkAAOSwknJX0R39 supposedly has 2kg of force, which seems a bit for 2 amps worth of electricity. Maybe it could work with a lever arrangement? 

[Cynic-al]

I believe the first one you shared is an idle air valve, you pipe it to bypass the butterfly a bit so that more air can pass and the revs pick up. It needs to be plumbed in before the vanturi in your carb though so it can draw more fuel too. I don't know if your carb will facilitate that?

The second looks like a solenoid. You could perhaps use that to push the throttle stop on the carb to raise the revs. Or maybe as said above to adance the timing. Not sure exactly how though. I don't think it would be easy to physically turn the dizzy accurately but maybe you could perform open heart surgery on one and mimic what the vac advance does?

 

 

 

[Bowie69]

You just need to push the base plate in the same way as a vacuum advance -in effect a throttle stop on the dizzy plate except not for throttle, but advance...

[Davo]

Thanks for the replies. I don't think I'll start poking holes into the distributor, though. I had an idea this: http://www.cps-service.co.uk/product_info.php/solenoids-starter-motor-solenoid-12v-for-alfa-romeo-fiat-saab-talbot-bedford-opel-vauxhall-p-582 work be strong enough to push on the throttle linkage somewhere, though actually mounting it and wiring it up would be another educational experience, do doubt.