MPG with Climate Off/On

[J7USS]

Just thought id share this discovery - or maybe just my mind playing games with me..

A mate of mine was on about Aircon/climate when switched on all the time does actually use more juice, Now I know that when aircon is used heavily it does effect your drinkage!!! soooooo I tried my car last week with ECON switched on (so im not using Aircon/climate) and I was surprised when I got 91miles out of £20 before the light came on, I usually average 75-80mls before the light comes on when ive always had my aircon/climate switched on, In fact I very rarely do turn it off.

Now on my 2nd test (with Aircon/climate switched back on permenant) my Petrol beep as just come on and Im at 72mls!!!!!

My driving hasnt been any different,All been round town and Main roads.

Is it just a Myth or what because Ive heard people say about how aircon batters petrol etc..

Is there someone out there to shine that light??

 

[grathies]

Im not convinced on it still, I know that youll be using less electrical power BUT the compressor is still being belt driven so there is still that 'loss' as such for the engine

Probably does make a difference but its minimal

 

[Carpy25]

the compressor has an electric clutch, the switch connects and disconnects drive

driving the compressor will drag the engine down , try this start engine switch the mainbeam on the engine revs will drop then the ecu will reset them and that just the load on the alternator

my 18 se does 3-4 mph more with the econ button on ,econ stops the compressor working

the G60 corrado was rated at 188 bhp(i think ) but the supercharger dragged to rating down to 160 bhp ,


Rob

 

[dan_b]

Aircon is responsible for reducing mpg by a small amount, difficult to say exactly how much though. One of the ways VW/Audi has reduced the "CO2" emissions on the "Bluemotion" models is by doing away with aircon altogether - as mentioned above not only is there an extra load on the engine every time the compressor cycles on (same as your fridge at home draws several hundred watts every few mins), meaning a bit of engine power has to go to that as well as pushing you along the road, there is the overall extra weight concerned with having aircon at all - something like 20kgs for all that kit (the compressor, the dryer, the weight of the coolant charge etc).

To be honest, the best way to improve your mpg whilst driving is to keep the tyres properly inflated and be a bit lighter with the right foot, in terms of accelerating, cruising speed and braking!

 

[grathies]

the G60 corrado was rated at 188 bhp(i think ) but the supercharger dragged to rating down to 160 bhp

Standard G60 lump wouldnt even produce 160bhp at the fly on most rollers but it makes up for those losses thru torque. The charger certainly is a drain on the power but then when you think that a standard 1.8 8v digi would be putting out 115bhpish that where it all comes relevent.

Plus while it does work on an electro magnetic clutch (remembered that as I was driving to my mates!) the pully is still being turned by the belt, and thats still a waste of some of the cars power as the belt when its not being used is longer than it needs to be so your loosing there too.

Best way to get more mpg is to buy a diesel, dont drive so fast and never take fat people in your car!

 

[46TheDoctor]

I know its not completely scientific and someone is bound to pick holes at it, but mythbusters did a test on aircon where MPG is concerned, and proved that although aircon does minimaly harm MPG, its still more fuel friendly than driving with your window open, which does kinda show how minimal the drag of an aircon pump is.

 

[andyccr]

Never made any measureable difference on the following that I have owned / still have :

1999 VW Golf Mk4 1.9Sdi - AIRCON
2000 Ford Focus 1.8 Zetec Petrol - AIRCON
2003 Skoda Octavia 1.8t vRS - CLIMATE
2003 Audi A4 Convertible 1.8t petrol - CLIMATE
2003 Ford Mondeo Estate 1.8 Duratec petrol - CLIMATE
2003 Mini Cooper 'S' 1.6 Supercharged petrol - CLIMATE
2005 Skoda Fabia 1.2 16v petrol - AIRCON
2007 '57' Ford Mondeo Estate 2.0TDCi diesel - CLIMATE

Will be able to post results for a 2002 E46 M3 Convertible, 2005 M3 Coupe, 2006 E60 5 series - but I'm sure they will all still show the same - NO measurable difference !


Considering most aircon pumps are rated at 2 or 3 hp, I fail to see how this can ever make any difference to fuel consumption that would be even moderately measurable.