Efficiency of vans?

Something Else · 28 May 2013 at 23:25

Work vans take about 90+ litres of fuel but only get like 350 miles or 400 a best most of the time. Not that anyone drives them carefully.

Lorries get like 1 or 2 mpg dont they?

breadturbo · 29 May 2013 at 03:02

I get 50mpg regular in my 61 scudo 2.0 dervs, that is 'trundling' at 62mph (limited)

trucks normally do 5-10mpg i think Somthing (motorway).

Scania · 29 May 2013 at 06:51

Trucks (i.e. a six axle artic running at full weight 44t) will average around 8-9mpg over mainly motorway/dual carriageway driving.

This figure will rise into the low teens if pulling a low weight, equally, running at full weight in stop start city traffic will get you down to 2-3mpg average.
A couple of examples,
Not much difference in average speed but a large variation in MPG - both 13litre Scania trucks.

Dogbreath · 29 May 2013 at 08:46

Scania said:
Trucks (i.e. a six axle artic running at full weight 44t) will average around 8-9mpg over mainly motorway/dual carriageway driving.

That's quite impressive really, I'd assumed it would be closer to half that.

DogsBody · 29 May 2013 at 11:09

Dogbreath said:
That's quite impressive really, I'd assumed it would be closer to half that.

It is impressive when you think it is a 13 litre engine pulling 44tonnes.
some cars weighing in at 2 tonnes only managed figures about 3 times that taking it steady on a run.

4T5 · 29 May 2013 at 11:12

Used to get 25-30 when running Transits with the old Banana lump in them, 35-40 seems pretty good to me.

Jez · 29 May 2013 at 11:15

Dogbreath said:
That's quite impressive really, I'd assumed it would be closer to half that.

That is very impressive when you consider that my V8 Range Rover cant even manage double that on a normal run.

breadturbo · 29 May 2013 at 16:08

The main reason they use less fuel I guess (im not sure what rpm they do at motorway speed) is engine speed,
I have a dodge ram 6.7 turbo derv, I tow a 5th wheel caravan from time to time (18tonnes ish inc the truck) and at 60ish shes doing 900rpm in 10th, whereas a regular diesel car will be 2k-2.5k dependent on gearing.

MeEsH BaKkA · 29 May 2013 at 17:33

In a 1.6 hdi Peugeot expert I get around 27mpg around London.

Muffin` · 29 May 2013 at 17:41

breadturbo said:
The main reason they use less fuel I guess (im not sure what rpm they do at motorway speed) is engine speed,
I have a dodge ram 6.7 turbo derv, I tow a 5th wheel caravan from time to time (18tonnes ish inc the truck) and at 60ish shes doing 900rpm in 10th, whereas a regular diesel car will be 2k-2.5k dependent on gearing.

Like that?

not bad... not bad at all...

Lakeland · 29 May 2013 at 17:52

35 to 40 mpg for that model with a light payload

Scania · 29 May 2013 at 19:11

breadturbo said:
The main reason they use less fuel I guess (im not sure what rpm they do at motorway speed) is engine speed,
I have a dodge ram 6.7 turbo derv, I tow a 5th wheel caravan from time to time (18tonnes ish inc the truck) and at 60ish shes doing 900rpm in 10th, whereas a regular diesel car will be 2k-2.5k dependent on gearing.

At 55MPH (it's limited speed) my Scania is doing roughly 1250RPM in 12th gear, regardless of weight i.e. loaded or empty it's the same.
Obviously fully freighted you have to drop 11th or 10th on motorway hills, not empty though.

GT3 · 29 May 2013 at 19:40

Mercedes 313cdi bluemotion - 22mpg round town is my daily average currently! Quite a way of quoted figures, maybe it will loosen up as it only has 3k miles on it.

DannyW · 29 May 2013 at 19:49

My mate has a T5 van hes never seen more then 35 mpg and goes on motorway everyday

Simon · 29 May 2013 at 22:43

clv101 said:
Looking at any car comparison website or the manufactures sites, it's easy to see the mpg of cars and compare them. The same data doesn't seem as easy to find for vans.

The T5 is available with five different 2.0 TDI engines ranging from 84 to 180PS, with 5, 6 or 7 speed boxes, with or without 4-wheel drive and in SWB or LWB. Loads of numbers on the websites but no mpg figures!

Surely from a commercial point of view this is useful information - why isn't it provided? What kind of efficiency does a 2800 kg 2.0TDI 140PS SWB T5 return? That same engine in a 1500 kg Golf will return 70mpg on a run - what would the T5 return?

Weight is largely irrelevant on a motorway. Aerodynamics are what matter.

Something Else · 30 May 2013 at 00:51

That is very impressive for the lorries tbh, I expected far less than that.

Orionaut · 30 May 2013 at 09:38

Somthing Else said:
That is very impressive for the lorries tbh, I expected far less than that.

Truck manufacturers go to a great deal of effort to ensure that their engines are as efficient as possible. Trucks use so much fuel over their lifetime that it is worth spending a great deal of money on squeezing every last fraction of an MPG out of them. (Far more so than with smaller vehicles and private cars! Which IMO are well past point of diminishing returns by now)

However, the efficiency is only achieved over a very narrow power/load band (Hence the 12 gears!) They can achieve remarkable efficiency at constant speed at their design load but it drops off quickly once conditions move away from this eg stop/start or even slowing down and speeding up!

Dogbreath · 30 May 2013 at 09:54

Simon said:
Weight is largely irrelevant on a motorway. Aerodynamics are what matter.

On an HGV I'd have thought rolling resistance would be pretty significant?

Simon · 30 May 2013 at 13:50

Dogbreath said:
On an HGV I'd have thought rolling resistance would be pretty significant?

Yeah sorry, I was talking about comparing a 1500kg Golf to a '2800kg' Van.

Apparently RR on a truck is responsible for 1/3rd of fuel consumption, a max speed of 56mph will limit the aero impact too