New perspective on bus fuel economy

[kjurkic]

Hi all

Found this little video, showing a BMW x5 averaging 39.5litres/100km - and that's the 3l 6cyl.

https://www.youtube.com/watch?v=s4lk7LEgWvA

that converts to 6MPG  

How hard do you have to be thrashing that poor little SUV?

I know I feel a LOT better about my DDS50

K

[kjurkic]

Edited original post to add link couldn't find way to delete this post tho'

K

[Jeremy]

All that video does is display the fuel readout on the dashboard, which means nothing unless you know what the car was doing to achieve that MPG - might have been climbing a mountain or wading through thick mud or something. As it happens I have a Range Rover with that same BMW engine, which is a diesel and good for 25mpg or so in regular driving - I think you'd struggle to thrash it enough on a normal road to get it down to a sustained 6mpg

Jeremy

[Geoff]

25 mpg isn't good milage either.  I had a 1985 MBZ that had a 5 clyinder turbo diesel and was disappointed when I figured out it got 25 mpg.  That's not good compared to today's diesels.

--Geoff

[Oonrahnjay]

25 mpg isn't good milage either.  I had a 1985 MBZ that had a 5 clyinder turbo diesel and was disappointed when I figured out it got 25 mpg.  That's not good compared to today's diesels.   
--Geoff

     I've averaged about 53 MPG (or about 68 MPImperialGallon, to compare to Jeremy's mileage) over 430,000 miles on my '03 TDI;  some trips have had 60 MPG+ tanks.

[Jeremy]

I've had lots of Range Rovers, and let's just say that 25mpg makes me happy!

I should also say that 25mpg is only a guess as I've never actually sat down and worked-out the fuel economy of any car I've ever owned, but this BMW-engined Range Rover is one of the cheapest cars to run I've ever had and I think 25mpg average is probably about right.

I also have another (v8 petrol) Range Rover and once did an identical 200-mile-ish trip in that and in my bus only a couple of weeks apart, and found that the fuel cost between the two vehicles was almost identical too. I'm still not sure if I should be delighted or outraged by that

Jeremy

[TomC]

Comparing a 1985 MB 300 Turbodiesel with mechanical injection and pre-chamber to today's Diesels with electronically controlled common rail fuel injection, air to air intercooling, etc. To make a point-my 1980 Kenworth with 8V-92TA 435hp, I averaged 4.8mpg-and I was happy with that. Today's trucks-drivers are complaining if they don't get at least 7mpg. With some getting over 8mpg driving carefully. Good Luck, TomC

[bigred]

My son had an older Ford Power Stroke diesel that got 10 mpg UNLESS he could get to an off road diesel pump .If he could ,the darned thing would get 22 mpg!!!

[Geoff]

My son had an older Ford Power Stroke diesel that got 10 mpg UNLESS he could get to an off road diesel pump .If he could ,the darned thing would get 22 mpg!!!

Are you saying that off road diesel fuel gives you better fuel mileage?  The dyed off road diesel is exactly the same fuel but with dye in it.  Plus my personal experience with the two fuels still was 25 mpg.

--Geoff

[bigred]

Are you saying that off road diesel fuel gives you better fuel mileage?  The dyed off road diesel is exactly the same fuel but with dye in it.  Plus my personal experience with the two fuels still was 25 mpg.

--Geoff  According to his findings it did ! The only experience I had was with my 8V92TA .While we were working on it a fuel truck made a delivery to a John Deer dealer across the road,and rather than get the bus out and go to a service station I asked the guy if he could fill me up.Said he would be happy to but he only had off road .I had him put it in the bus and it seemed to get better mileage.Didn't actually check that but I know for a fact it ran better than it had ever run before . And thats a fact with my hand up !!!   

[Brassman]

     I've averaged about 53 MPG (or about 68 MPImperialGallon, to compare to Jeremy's mileage) over 430,000 miles on my '03 TDI;  some trips have had 60 MPG+ tanks.

Have you done mods to your '03 TDI. I have an '06 and I get 46-48 mpg. Haven't done anything to modify -- yet.

[Oonrahnjay]

I've averaged about 53 MPG (or about 68 MPImperialGallon, to compare to Jeremy's mileage) over 430,000 miles on my '03 TDI;  some trips have had 60 MPG+ tanks. 

Have you done mods to your '03 TDI. I have an '06 and I get 46-48 mpg. Haven't done anything to modify -- yet. 

     The big issue is that the '06 is an "A5" chassis, the '03 is an "A4".  The later models are about 450 - 500 pounds heavier than the '03.  Also, the engine in the '06 is a PD-injection where the fuel injectors in the engine are powered by cam lobes on the cam shaft while the '03 has an fuel system that's distributed-injection; all the injection pressure is provided by the fuel pump.  The PD systems on big trucks proved to give good fuel economy (most have been superceded by "high pressure common rail" systems for emissions reasons, I think -- that's what VW has done on it's latest TDI cars, '09 and later) but they never gave as good mileage on VWs as the distributed-injection models (Bosch calls them "VE" systems, initials for the German words).
     So, you're dealing with a couple of different reasons that an '06 will probably not give as good mileage as an '03.  To answer your question directly, I have "VAG-Com" software that allows me to tweak the base injection setting in the ECM for a slight improvement, and I've installed a 5th gear set from a Vanagon to make the 5th gear a slight overdrive.  Finally, I'm old and retired -- I don't have anywhere I need to go fast so I drive slow, plus I live in flat country with traffic that's not too heavy and speed limits are often 55.   

HTH, BH