Fuel economy question
A quick question....purely about fuel economy and nothing else like load handling/stability..
I will be towing a Trigano Silver 380 to Provence this June, it's a light caravan btw.
I'll be pulling it with a Renault Meganne 1.5 diesel.
Let's say I would be carrying 100kg of things that could be either stored in the van or the car....does the fuel economy alter with either storage option (car v. caravan) or would it be exactly the same?
Comments
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You would be towing the same weight, regardless of where you put it.
The two factors that will affect the mpg are weight and drag.
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I would have thought the better balanced your set up is the better your fuel consumption. I would not have thought it would matter where the weight was as long as the optimum towing balance was achieved. Seem logical to me, no idea if I am correct.
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It might not make much difference but every correction that your car has to make to the direction of travel (up/down or side-to-side) of your caravan will consume energy and have an adverse effect on mpg. So you do need to consider where you put your weight.
Carry as much weight as you can in the car. Keep weight in the van as low and near to the van axle as possible, while maintaining the noseweight at maximum.0 -
I think the biggest factor that affects consumption is wind resistance. Polish the van and, if you are driving a convertible, shave your head.
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I've talked with a physics professor today, and he states that the load should be carried in the car as near to the drive staft as possible for best economy due to resistance v load theory...he did draw me an equation, but I got lost after the words "let me show you"....
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Agree with what people have already said:
It should make very little difference where you put the weight. weight only really affects frictional losses from the tyres and bearings etc (assuming a set weight). Obviouisly the heavier the total outfit, the more energy will be needed in any elevation change (potential energy).
What ever is the most stable and most balance configuration will give you the least losses (marginal gain).
But these pale into insignificance against the air resistance losses - drag from the van, which you can do little about!
Remember that drag is equal to half the density x velocity squared x area x drag coefficient. The important bit is the velocity squared, so the drag gets much much more as the speed increases - doubling your speed quadruples the drag!
And the power needed increases as a cube of velocity doubling your speed, means 4x the drag and 8x the power needed and power comes from burning fuel!
If you are worried about fuel consumption, slow down a bit, it will make a significant difference!
(but will get you parped and bring us caravaners into disrepute!).
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With a good load in the back of my car (2.0TDi estate 4x4) awning poles, BBQ etc., etc. and caravan loaded also 2 bikes on the car roof all well within my weight / load limits of course. German / Czech motorways at 50mph using Ultimate diesel, not complaining at 37mpg
. But then at 40mph, for safe towing, same load in a head on gale force wind heading for Dunkirk to catch the ferry, it did drop to just under 30mpg.0 -
Reduce your speed and wait for a following wind, the second may not be exactly practical but they are the two main causes of high fuel consumption. One thing the trip computer in a modern car allows you to do is monitor fuel consumption in different situations.
Going south last year over the A75 against a north wind I reckon we were losing 3-4 MPG over what we would normally expect on that route I appreciate its not exactly scientific but it was very noticable.0 -
We and I say we as OH records mileage and fill quantites, monitor ours out of intrest, my last car invariably did between 24.5 and 26 mpg over nearly 50K miles towing and it did not depress me at all because that what it took to do what we needed it to do..
Write your comments here...I would have to be going downhill with a following wind for that figure.
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We and I say we as OH records mileage and fill quantites, monitor ours out of intrest, my last car invariably did between 24.5 and 26 mpg over nearly 50K miles towing and it did not depress me at all because that what it took to do what we needed it to do..
Write your comments here...I would have to be going downhill with a following wind for that figure.
What have you got?
Write your comments here...Lexis 350 Navigator. Brilliant car in every way except mpg.
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We and I say we as OH records mileage and fill quantites, monitor ours out of intrest, my last car invariably did between 24.5 and 26 mpg over nearly 50K miles towing and it did not depress me at all because that what it took to do what we needed it to do..
Write your comments here...I would have to be going downhill with a following wind for that figure.
What have you got?
Write your comments here...Lexis 350 Navigator. Brilliant car in every way except mpg.
When on the road ......
my R320 does around 21/22 while towing, mid/high 20s around town & about 30/31 at motorway(ish
)
speeds0 -
I suspect it depends on the rolling resistance of the tyres in use. The tyres with the lower rolling resistance at the new loading, would be the best to take the load. I suspect that unless the car is already close to its maximum tyre loading it will be the least resistive, as it is the more probable to have low resistence tyres fitted and probably more loading reserves than the ones on the caravan.
All though I suspect will turn out in practice to be half a part of nothing difference in real terms. Erring on the upper side of the allowed inflation pressures would be wise for cutting down on the rolling resistance.
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Loading might have some effect but it will be negligible. The two main factors as said before are weight and wind resistance. You can keep weight to a minimum but any saving will not be great so to keep fuel useage down driving technique is the best way
to save. Speed is probably the biggest area but you do have to get there.0 -
Briang! Have had 3 of those and put 90,000 on each! Great motors and I wish I still had one! Currently on a Merc ML300 auto. Its great on solo fuel consumption and being a V6 smoother, but I'd swap it for an LC4 tomorrow.
The Merc is a "Blue Efficiency" version & I get a solo average of about 33-34 and once lightly laden 40 mpg.
Towing a heavy Coachman Pastiche 565/4 at about 24 mpg on average. (pressing on)
Even then, there's nothing like a landcruiser! Stick with it!
TF
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Briang! Have had 3 of those and put 90,000 on each! Great motors and I wish I still had one! Currently on a Merc ML300 auto. Its great on solo fuel consumption and being a V6 smoother, but I'd swap it for an LC4 tomorrow.
The Merc is a "Blue Efficiency" version & I get a solo average of about 33-34 and once lightly laden 40 mpg.
Towing a heavy Coachman Pastiche 565/4 at about 24 mpg on average. (pressing on)
Even then, there's nothing like a landcruiser! Stick with it!
TF
Tigerfish,This is about the same fuel consumpsion as what i get on my LC4. 190bhp 410 torque what more do you need Telegraph Hill at the end of the M5 Exeter going up there at 60mph no problem at all, that is a test on it's own. Will not want to sell it.
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.... Telegraph Hill at the end of the M5 Exeter going up there at 60mph no problem at all, that is a test on it's own. Will not want to sell it.
Went up there many years ago in a hired Fiesta. 4 of us in it & it just about got to the top
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.... Telegraph Hill at the end of the M5 Exeter going up there at 60mph no problem at all, that is a test on it's own. Will not want to sell it.
Went up there many years ago in a hired Fiesta. 4 of us in it & it just about got to the top
Write your comments here...That will be with uniforms on then.
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Telegraph Hill was the reason we bought the Series llA (avatar) back in the early 70s. Every other car we had needed new big ends after towing up that hill. These days any decent tow car will cope without problems but the hills in the SW are the reason we always chose beefy 4WDs for towing. Our last, a Shogun, could easily exceed the speed limit towing up Telegraph Hill.
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We sail up Telegraph Hill in fourth with the Bailey on the hook of our Sportage on the way to Hillhead each year the temp gauge does not alter
That's as it should be. As I said, these days it's different with modern cars.
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and going uphill or into the wind or both will make it even worse.
