Technical Always breathing hot air?

[mqsash]

Never realized till today that the black box which holds the air filter actually has two air intake openings!! One connects to the air intake pipe - I guess for breathing cold air, the other one (which I discovered today at the bottom of the box) opens directly into the engine bay - probably for hot air?

A flap between the two openings connected to some kind of spring + lever which controls which intake should be opened or closed. But I'm not sure whether this is functional in my Uno

I checked when the engine was hot (after about 10km drive) as well as when the engine was cold, in both cases the flap position was such that the actual air intake was closed and the engine bay intake was open!

Anbody aware of how this should work? Is this the right position? Cause if it stays the way it is, it means that the engine is always breathing the hot air from the engine bay and never gets fresh cold air. Won't that affect performance?

mqs

 

[EssexUno]

Quite frankly the switch is broken, it uses wax like the thermostat, when its cold it retracts and pulls the flap up and when it's hot should extend and push the flap closed but like many things on the uno, they just stop workng lol. Just disconnect the flap from the switch so that itjust has cold air, you should not have a problem with carb iceing if you have an injection model but if you have a carb model then when the weathers really cold you should connect the flap to the broken switch so that you don't get carb iceing.

Hope this helps
Dan

 

[mqsash]

Thanks Dan,

In the part of the world where I live, temperatures never get close to freezing. So I guess I could just leave the switch disconnected

Just wondering though - what would be the effects on the car / drive quality, mileage etc of always using the hot air ? In other words what changes should I expect (if any) once I disconnect the switch?

Thanks again Dan

mqs

 

[rawill]

Cold air makes the engine go better so long as it is not so cold that the carburettor ices up. So having the hot air from in the engine bay go in will make it less economical, (slightly).

 

[EssexUno]

I don't know if it will be a noticble gain but cold air is dencer than warm air, this means that more air can fit into the engine cylinder as it takes up less space, which in turn means more fuel can be added, this means more power. You may notice this happen when you drive through a patch of fog as the fog is dencer than the air around it. You don't have to adjust the fueling as it is done automatically.

Dan

 

[alexGS]

To confirm - in India, definitely fix the flap in the cold-air intake position

The thermostat for that flap is a very common failure and usually fails in a midway position. Most of the time you are better off with a cold air intake for the reasons Dan stated.

-Alex