Throbbing with windows down. Arrgghh...

[Groot]

Hi there.
Anyone found a way to defeat the awful throbbing resonance that occurs with the windows down? I was optimistic when I acquired my second A2, with its two extra electric windows in the rear, that I would find a combination of openings which would allow fresh-air motoring in comfort. But no luck so far. Aircon is great for stifling summers but this time of year I want to feel the breeze. Off to the south of France in three weeks....any ideas?
Groot!

PS Possibly my only gripe though!

[ULP]

I found opening opposing front and rear windows (i.e. front passengers and rear drivers side) does the trick although you still get some buffetting.

[chucknaldo]

You can use wind deflectors. They can be found on ebay.

[vkx245l]

Similar to ULP, I open both the rears a little and then one of the fronts.
Just remember how lucky you are to be able to do this from the comfort of the drivers seat - The rear electric windows were an option!

[Groot]

Ha ha! Talk about opening windows and we get the first rain in months. Thanks for you thoughts.....will test-out when the sun returns.
Groot

[alexwharton]

Keep em shut and stick your climate control on.

[MPG Lover]

Keep em shut and stick your climate control on.

And lose about 3MPG? No chance ;)

[Skipton01]

And lose about 3MPG? No chance ;)
You'll drop more than 3mpg if you have the windows open, just by loss of aerodynamic efficiency!

Cheers,

Mike

[Groot]

Thinking about aircon economy, how about this in hot weather: switch to recirculating mode. That way you keep the already cooled air in the car and the cooler is working much less. Need to toggle the recirc button regularly to let some fresh air in but this must represent quite an energy/mpg saving?
Groot!

[andyman]

OMG Sorry but Comfort over cost anyday!!.

[Groot]

Ah well, I don't feel that comfortable about super-cooling air and then instantly ejecting it out of the rear of the car at great velocity. Same as it is not a great idea to aircon a house with the windows open. Economically and environmentally dodgy!
Groot!

[ULP]

as it is not a great idea to aircon a house with the windows open. Economically and environmentally dodgy!
Groot!

...and you'll kill the condenser in minutes as you are trying to cool the whole atmosphere on the earth!

It is reccomended that to use A/C effectively on a hot day open the windows, turn the fan onto full speed to push out the super-heated air inside the car. Then close the windows, turn recirculation on and then wait for the cabin temperature to drop down to the right temperature then just switch the recirculation off.

Recirculation increases the amount of carbon monoxide in the car - it really shouldn't be used unless when first cooling and in high-pollution.

Pulling in air from the outside is barely any more of a stress on the system than cooling internal air (you'd be suprised how quick the recirculated air heats up in a glass-box).

Not to mention you'll increase bacterial growth on your A/C intake - think of that extra trip once a year to have it cleaned, and the effects that will have on the environment... Not to mention the extra fuel used to take your car in for an A/C rebuild when the unit hasn't been used for ages and all the bearings are seized and pipe joints corroded. All the extra carbon emission created in the production/ shipping of replacement parts etc. etc. etc. etc.

As Mike correctly points out, opening a window turns our aerodynamic boxes with a beautifully low cd figure into a whopping great parachute - the A/C economy loss v open window economy loss is neither here nor there. I suspect under 35mph-ish then open windows will be better as the drag is minimal, but above that open windows will start to harm the economy.

If you want to open the windows then do, but likewise use the A/C if you want too!

[Groot]

Some interesting points ULP and the recommended cabin cooling procedure seems sensible.

You mentioned the A2's very low CD (with windows closed) and it occurs to me that maybe the horrible throbbing with the windows open is actually because of this?? If so, I'd have to say it's a great feature!

Groot!