I was tipping at Waitrose Bracknell last wee and got chatting to another driver while we were waiting for our paperwork, and for whatever reason, the subject of my Air Con needing re-gassing came up. This other driver then proceeded to tell me about a bloke he worked for, had 5 new FH’s delivered and then promptly cut the Air Con belts off them to save fuel when the drivers use the Air Con… Personally i think the guy was chatting ■■■■■■■■ but thats neither here nor there…
Now i know on a Car, Air Con does affect Fuel and Performance, having conducted my own little experiment with my old Vectra GSi, it was evident it was more thirsty and not as quick of the mark…
Does the same apply to a truck??
Has anyone tried it??
If so i would be curious to know what the difference in fuel consumption was…
yes it will increase fuel useage
but whats cheaper a nice cool
alert driver or one that is
knackered because its too
warm,& who is more likely
to make mistakes;
Cutting the belt was plain daft no doubt learned all he knows at university.If the motor left the factory with it fitted best not to interfere, as been said you need it on some occasions.
everything requires energy, the energy has to come from somewhere, nothing can be created or destroyed, only transformed. Everything on your truck gets its energy from the fuel it burns. From your phone charger to your a/c, all will burn fuel to run them.
However compared to the amount of energy used to move a 40 tonne brick at 60mph i doubt you will notice much at the pump. A relative who is a farmer used to say the a/c cost a couple of pence an hour but was a life saver as most of his work is hedge cutting where you have to have the windows shut to stop whatever is in the hedge hitting you. His tractors have bullet proof glass, one of them has a 3" length of wire wedged in the glass half each side
Agreed thking the a/c belts off is pretty dumb, why not just take the fuse out or disconnect the switch?
BuzzardBoy:
This other driver then proceeded to tell me about a bloke he worked for, had 5 new FH’s delivered and then promptly cut the Air Con belts off them to save fuel when the drivers use the Air Con… Personally i think the guy was chatting ■■■■■■■■ but thats neither here nor there…
Not sure about Volvo’s, but most vehicles use one single poly belt to drive everything to reduce cost and friction, so he was more than likely talking ■■■■■■■■ about having the belts cut off, and I can’t see aircon on a truck using that much more fuel, theres only half as much glass as in a car, and with the windows more vertical, the area inside the cab exposed to direct sun is far less.
lee hawke:
on a truck wont make 1 bit of difference tried and tested it before
I’ve even tried it in my car. Done a tank full of fuel with aircon on and a tank full with aircon off. The computer didn’t suggest any real difference.
I even got the calculator out and the computer was right!
BuzzardBoy:
This other driver then proceeded to tell me about a bloke he worked for, had 5 new FH’s delivered and then promptly cut the Air Con belts off them to save fuel when the drivers use the Air Con… Personally i think the guy was chatting ■■■■■■■■ but thats neither here nor there.
That story has been around for a few years now, sometimes with minor variations in the number of vehicles or the method of disabling the a/c, so although someone, somewhere may have done this at some time the amount of retelling does put it in the Driver’s Urban Myth/BS stories category.
Windows down vs. air conditioning
“Urban puzzle”: it is more efficient, on a hot day, to run with the A/C on and windows up than to run with windows down (b/c of increasing car’s drag).
Computer-based mpg measurements: * 11.7/11.8 with A/C on and windows up * 11.7/11.8 with A/C off and windows up * 11.3 with A/C off and windows down
So, according to the computer, it’s better to use A/C with windows up.
This was too quick and easy for TV, so they decided to stage a seven hour marathon, race-til-you’re-empty duel, with Jamie driving an SUV with A/C on and Adam driving an SUV with windows down. Though, once the safety inspector intervened, it was no longer a seven-hour marathon, it was a bit slower (45mph instead of 55mph), and a lot shorter (only 5 gallons each).
Jamie’s A/C car ran out of gas first – Adam’s windows down SUV ran for another 30 laps – completely contradicting the computer mpg estimate. Computer estimate based on air flow into the engine, so it would appear that it is unable to properly model the difference between A/C and windows down.
Mythbusted
Mythbusters did this a long time ago EXACT SAME CAR same speed same track etc etc and Air con was better than having windows down when it comes to the drag caused.
There has been lots of discussion about this in America as you might imagine.
The consensus seems to be that: On Freeways/open roads (Motorways) shut the windows turn the air con on, and on urban roads with traffic and stop start driving then open the windows and turn the air con off.
This is for cars/SUV’s of course. With at truck i can’t imagine it makes much difference either way.
Windows down vs. air conditioning
“Urban puzzle”: it is more efficient, on a hot day, to run with the A/C on and windows up than to run with windows down (b/c of increasing car’s drag).
Computer-based mpg measurements: * 11.7/11.8 with A/C on and windows up * 11.7/11.8 with A/C off and windows up * 11.3 with A/C off and windows down
So, according to the computer, it’s better to use A/C with windows up.
This was too quick and easy for TV, so they decided to stage a seven hour marathon, race-til-you’re-empty duel, with Jamie driving an SUV with A/C on and Adam driving an SUV with windows down. Though, once the safety inspector intervened, it was no longer a seven-hour marathon, it was a bit slower (45mph instead of 55mph), and a lot shorter (only 5 gallons each).
Jamie’s A/C car ran out of gas first – Adam’s windows down SUV ran for another 30 laps – completely contradicting the computer mpg estimate. Computer estimate based on air flow into the engine, so it would appear that it is unable to properly model the difference between A/C and windows down.
Mythbusted
Mythbusters did this a long time ago EXACT SAME CAR same speed same track etc etc and Air con was better than having windows down when it comes to the drag caused.
Umm, a test on car does really bear much relevance to a full sized truck. I do remember that test Mythbusters did, it was a petrol US thing. They cocked it up once before, got complaints, and not that sure they did it very accurately the last time.
I am assuming the compressor is not much bigger than a car one, but, of course the engine is much bigger. I would guess on a full size truck 400 to 500, lets say, its not going to make much difference. Remeber Volvos AC default setting is on, although there is a switch to stwitch it off. Don’t know if the very latest models are the same or not…
So, in summary, my guess it would barely make any difference.
i would have thought that considering how much torque the truck engine’s have compared to how much is needed to drive an air con pump that it would make next to no noticible difference. what about them ones that you can buy and bolt onto the roof, don’t they just run off 24V electricity?
to be honest,i dont think so.
my truck in winter,summer,tramping or trunking,doesnt use any more or less diesel with the air con on,and furthermore,i dont care if it does,as long as in the summer i dont end up with betty swollocks!!.
