Driving in mountains.

[aishadeol]

I went for a drive with my friend on mountains. When we were driving on steep & long hills, she asked to turn-off the the radio & A/C. I understand the A/C but why radio? Because to my knowledge radio is battery operated not by car engine. Also she asked us to close all window glasses. Can any one explain the region behind this?

[Southwest Dave]

Hello and welcome to the RTA forums !

Obviously the A/C can cause some loss in power, but the radio would not make any difference IMO. One of the great debates about having the A/C turned off for more power and better mpg consumption, is that many believe by switching off the A/C and then having the windows open instead, causes increased drag by air buffeting through the car. The 'drag' then has the same effect as reduced power output, and will use more gas. This is most likely what your friend has heard, that by turning the A/C off and opening the windows means there is no 'gain'.

Personally I think it is negligible either way, particularly on more modern vehicles.

[Midwest Michael]

Welcome to the RTA Forum!

I suspect your friend was working off some old wives tales. Technically, everything does run off the engine (as the battery is recharged by the engine via the alternator) but the radio draws so little power it basically should have no impact.

The windows rolled up also is a little easier on the engine, since you're reducing drag that you'd have with the windows down, which can notice to a degree with gas mileage.

However, in all honesty, if you've got a car that is running properly particularly with regards to the cooling system, it is very rare that you should have to even turn off the AC. Most cars can more than handle anything that can be built from a roads perspective.