General Panda 4x4 twin-air mpg

Currently reading:
General Panda 4x4 twin-air mpg

I think we can conclude that aircon on the TwinAir motor does use extra fuel.
Also, I think the more economical your driving style the more apparent it is.

Running the aircon on any car will reduce economy. A/C takes power from the engine, and that power has to be paid for in fuel.

How much, and whether or not you are able to notice the difference, depends on many factors but is basically down to how much cooling is required, and how long it's switched on for.

Ecodrivers will certainly notice a bigger difference, partly because they are using less fuel to cover a given distance, and partly because it takes them a little longer to cover that distance, so it's a 'double-whammy' effect.

In the worst case scenario in my 1.2, running the A/C reduces economy by over 10mpg.
 
They're also based upon the inaccurate trip readout also I take it and not a brim to brim test :confused:

That's true. But I was not going to stop and top up with petrol, at motorway prices, every 20 ~ 30 minutes ! (and this would still have been subject to error due to different 'brim' levels when only filling up with 2~3 litres, different fuel types, different driving speeds around service stations, etc.)

The trip computer measurements may not be highly accurate, but should be fairly consistent between the two tests. For certain, the error in the trip computer measurement between the two tests is much smaller than the indicated 10% effect due to the aircon being on or off.

I'm not trying to specify the exact effect of the aircon, but I am saying that the effect of using the aircon, on my car, at 70 mph on a fairly level road is to increase fuel consumption by about 10% (say 5% ~ 15%, taking error into account).
 
The trip computer measurements may not be highly accurate, but should be fairly consistent between the two tests. For certain, the error in the trip computer measurement between the two tests is much smaller than the indicated 10% effect due to the aircon being on or off.

Absoulutely. The trip computer isn't particularly accurate, but it is consistent between readings when used in this way.

I'm not trying to specify the exact effect of the aircon, but I am saying that the effect of using the aircon, on my car, at 70 mph on a fairly level road is to increase fuel consumption by about 10% (say 5% ~ 15%, taking error into account).

Yes, at 70mph, that's exactly the effect I'd expect to see.
 
Running the aircon on any car will reduce economy. A/C takes power from the engine, and that power has to be paid for in fuel.

This seems logical, assuming that engine efficiency is a fixed parameter.

However, both my previous cars (Renault Clio dCi 80 and Alfa Mito 1.3JTDM-2)
appeared to use no extra fuel with air-conditioning on, despite my checking
many times, over thousands of miles.

My theory is that the extra load improves the efficiency of the turbodiesel
at low power levels (I usually drive deliberately for maximum economy)

Unfortunately, this doesn't seem to apply to the petrol Twinair, for which
I'm finding a fuel penalty of about 6% with the air-con. on :(

It's still a great engine though, and my Trekking's managing to do
better than 50MPG average wherever I go :D



Chris
 
I think that the extra torque of Diesels is better able to carry the load of A/C compressors than relatively low torque petrols, which need to rev higher, particularly at idle, to prevent stalling.

I've driven small engine petrols - admittedly a long time ago - which were noticeably slower and more laboured, and thirsty, when the A/C cut in.

Having said that, the TA does not feel to be struggling with the compressor operating, but then this is probably masked by clever software and a less power hungry modern compressor.

I was a passenger last night in a VW Polo, the one with the small three cylinder engine, and I could barely notice the compressor cutting in, either by sound or by engine note, and the car became ice cold very quickly.
 
My old Daewoo Leganza was more economical with the aircon on than off !
This was because I only used the aircon when the weather was really hot, and I tended to slow down to enjoy the cool breeze !

If you've got air con and its hot then use it, otherwise why bother paying for it in the first place. I'd use my MJ aircon if it worked !

Don't forget to put the recirculation on as this will minimise the energy requirement. Don't forget that the car needs more energy to cool it down initially, and then less to maintain it at that temperature, so longer runs will be more economical.
 
Have just returned from weekend in Norwich and using ac most of the time achieved 41.10 mpg using brimful tank to brimful tank...mostly Motorway and dual carriageway...52 mph average according to trip.
Engine still feels tight so should see figures increase.
Regards
 
Just done a 140 round trip to the royal welsh show in my 4x4. Mainly single carriage a roads, lots if bends and hills and trip computer showed 52mpg. All miles done with ac on and still only done 660 miles in total.
I noticed that two things kill your mpg: speed and hills. 40mph stuck behind.a lorry was the most economical. Getting about 35mpg in my daily 2.5 mile commute to work. Downhill getting to work, uphill going home.
 
Thanks deeyup, that was very interesting.

The only bit that made no sense was the comment: "...it would make a impact in terms of protecting the environment.”

Given this test was about which actions make the most difference to the cost of motoring (at least in terms of money spent at the pump), if they wanted to make a valid environmental point, then surely they should subject that to the same rigours and measure all the major factors. If they were to do this, they may find that measures that shorten a vehicles useful life or make it difficult to recycle have proportionately far greater impact than the amount of fuel used.

However, politicians in the UK generally don't want us to hold onto cars for too long and they need a 'green smokescreen' to hide the main driver which is finding ways to keep increasing the tax take without people voting them out of office.

All IMHO of course!!:D
 
Just reviving this thread! We have had the 4x4 for just over a year, during which time it has covered 11000 miles with average consumption of 44mpg. After talking to a neighbour in the village who has an identical car and does the exact same route, she gets 48 mpg... The difference is she never used the ECO button while I have used it most of the time!!!!

I have now switched the button off and am getting 48mpg!! Some what is the function of the ECO button other than to increase fuel consumption and decrease driving fun?
 
Just reviving this thread! We have had the 4x4 for just over a year, during which time it has covered 11000 miles with average consumption of 44mpg. After talking to a neighbour in the village who has an identical car and does the exact same route, she gets 48 mpg... The difference is she never used the ECO button while I have used it most of the time!!!!

I have now switched the button off and am getting 48mpg!! Some what is the function of the ECO button other than to increase fuel consumption and decrease driving fun?



have BOTH had oil changes,( and ECU resets..??)


Charlie - Punto TA - 49mpg
 
As far as I'm aware neither has had either! I'm about to do an oil and filter change at local Indy garage ahead of the 2 year service interval. Car has not been back to dealer since supplied as no problems or need
 
I reckon Eco returns better mpg only if driven in an 'Eco' style, ie, smoothly and carefully. If you try and push it in Eco the engine has to do more work to what you ask of it and hence is less economical. I have tried a few 'eco' runs in my 500 and definitely get better results with Eco (67mpg over 60 miles is best so far!) then normal mode, it sort of forces you to drive economically but if you fight it you pay! Normal mode driven smoothly can return good results too. A lot of the results you get though are down to driving style, terrain, route etc etc. My average every day mpg is around 45 over a tank in normal mode with mixed driving but I can easily get up to 60mpg over a single journey (5K on car to date).
 
Last edited:
As far as I'm aware neither has had either! I'm about to do an oil and filter change at local Indy garage ahead of the 2 year service interval. Car has not been back to dealer since supplied as no problems or need

I had my 100HP serviced by an independent and the 4x4 TA will be in future. They take the car to the local service-only Fiat garage to have the service indicator reset.
 
Back
Top