I shouldn't care about economy but I do - Why?
Discussion
I did an economy run today to see what MPG my car can achieve. Just over 100 miles (Devon to Wiltshire), cruising at 70 MPH (slight traffic delay around Bristol) and I averaged 60.3MPG.
Now I usually average about 45mpg in day to day driving but I normally cruise at 80/85. Of course the 45 mpg average includes ALL driving. Cruising at 80/85, I'd get 50 ish mpg but that doesn't include cold starts, town driving, A roads, etc, hence the overall 45 mpg average.
Going back to the original question though, I don't know why I care. I have a fuel card that includes private mileage so why do I still want to max out economy from time to time?
PS - Car is a 520d Touring Auto. Total average mpg is worked brim to brim, the 100 miles was from trip computer HOWEVER over the past 3,000 miles I have used the hidden menu to apply a correction factor to the computer mpg reading. The computer reading is now always +/- 0.5 mpg from true brim to brim calculations.
Now I usually average about 45mpg in day to day driving but I normally cruise at 80/85. Of course the 45 mpg average includes ALL driving. Cruising at 80/85, I'd get 50 ish mpg but that doesn't include cold starts, town driving, A roads, etc, hence the overall 45 mpg average.
Going back to the original question though, I don't know why I care. I have a fuel card that includes private mileage so why do I still want to max out economy from time to time?
PS - Car is a 520d Touring Auto. Total average mpg is worked brim to brim, the 100 miles was from trip computer HOWEVER over the past 3,000 miles I have used the hidden menu to apply a correction factor to the computer mpg reading. The computer reading is now always +/- 0.5 mpg from true brim to brim calculations.
redgriff500 said:
I once had a BMW with the economy gauge (IIRC) under the speedo and I found I accelerated less as when it was dropping below 5mpg it was disconcerting.
Fixed it by putting some black tape over the front.
Ignorance is bliss.
Sodding hell it gets me every time. The lowest I got my old peugeot to read on the digital trip computer for real time MPG was 8.1, and that was flat out in first/second.Fixed it by putting some black tape over the front.
Ignorance is bliss.
Seeing the needle drop to 0mpg on the BMW makes me cry. It basically stays down there until you reach crusing speed.
redgriff500 said:
I once had a BMW with the economy gauge (IIRC) under the speedo and I found I accelerated less as when it was dropping below 5mpg it was disconcerting.
Fixed it by putting some black tape over the front.
Ignorance is bliss.
My E46 has this, you may be onto something with the black tapeFixed it by putting some black tape over the front.
Ignorance is bliss.
matthias73 said:
Sodding hell it gets me every time. The lowest I got my old peugeot to read on the digital trip computer for real time MPG was 8.1, and that was flat out in first/second.
Seeing the needle drop to 0mpg on the BMW makes me cry. It basically stays down there until you reach crusing speed.
The 2001 V6 C5 I had used to drop to about 7mph real time under full throttle, but it would read 999 mpg with foot off throttle going down hill.Seeing the needle drop to 0mpg on the BMW makes me cry. It basically stays down there until you reach crusing speed.
My new BMW has a analogue reading - I am not sure it matches reality as it drops to zero when moving, but sitting in traffic (if stop start doesn't kicks in) it is reading 80mpg. I just ignore it. I am also suspicious of the digital trip consumption - as it seems to swing as much on a journey close to end of tank as it did second journey (I reset when I fill the tank) - from the one brimming of tank I have been able to measure - It seems more optimistic than I have seen before
My new pick up truck displays instantaneous mpg, even the lightest acceleration puts it below 20mpg, 'normal' acceleration (not particularly hard, just trying to not be a mobile road block), shows below 10mpg. 
If I drive incredibly delicately I can get 34mpg (brim to brim). But the odd thing is, it actually does better mpg on winding A roads, than on dual carriageway/motorway. I thought that 65-70mph would be nice and efficient, but cruise mpg starts to drop significantly when you get above 50mph.
To read that a 520d (and an auto one at that) will do 60mpg makes me wonder why the pick it so much worse. Weight can't be that much higher - the truck is 1978kg, and the 5 series must be 1700kg these days? Tyres are medium tread, not full off road knobbly things, so they shouldn't be too inefficient. That only leaves the aerodynamics. I guess the frontal area is going to be a lot bigger than a car, along with the shape of the bed at the back, possibly explains some of the difference.
I'm hoping that it will improve further as the engine loosens up, but I don't think it's going to get much better. If the mpg wasn't on display I probably wouldn't be nursing it to coax economy up. If I drove it the same way I used to drive my astravan, I'd be lucky to get 20mpg out of a tank.
If I drive incredibly delicately I can get 34mpg (brim to brim). But the odd thing is, it actually does better mpg on winding A roads, than on dual carriageway/motorway. I thought that 65-70mph would be nice and efficient, but cruise mpg starts to drop significantly when you get above 50mph.To read that a 520d (and an auto one at that) will do 60mpg makes me wonder why the pick it so much worse. Weight can't be that much higher - the truck is 1978kg, and the 5 series must be 1700kg these days? Tyres are medium tread, not full off road knobbly things, so they shouldn't be too inefficient. That only leaves the aerodynamics. I guess the frontal area is going to be a lot bigger than a car, along with the shape of the bed at the back, possibly explains some of the difference.
I'm hoping that it will improve further as the engine loosens up, but I don't think it's going to get much better. If the mpg wasn't on display I probably wouldn't be nursing it to coax economy up. If I drove it the same way I used to drive my astravan, I'd be lucky to get 20mpg out of a tank.
mjb1 said:
I thought that 65-70mph would be nice and efficient, but cruise mpg starts to drop significantly when you get above 50mph.
IIRC aero starts to matter above 50 and yes pick ups have terrible aero, their gearing is usually low too.Surprisingly from the test results I've seen dropping / removing the tailgate doesn't help but the hard rear covers do. I suspect the soft load covers might too.
redgriff500 said:
I once had a BMW with the economy gauge (IIRC) under the speedo and I found I accelerated less as when it was dropping below 5mpg it was disconcerting.
Fixed it by putting some black tape over the front.
Ignorance is bliss.
I just picked up a 328i with the swingy gauge. I know the feeling you're talking about. It's like it's taunting me.Fixed it by putting some black tape over the front.
Ignorance is bliss.
I to have a company fuel card. I do care about economy because as with any business, costs are monitored. We must give mileage with each fill also. I don't know if the bills are ever checked, I've never been questioned on it but if I did I can prove my mpg and miles per tank are all about right for the vehicle.
BFG TERRANO said:
I to have a company fuel card. I don't know if the bills are ever checked,
They are - that's the purpose of the scheme.Many years ago I was forced into having a Co. car - a Rover 214 when I was driving Cosworths / Integrales etc as managers got upset that my cars were substantially better than theirs.
Needless to say I abused the hell out of it.
I received paperwork from the fuel card supplier with "Abuse" stamped across it for managing sub 30mpg and getting through front tyres within 5k.
I suggested if they didn't like how I drove their car that they should withdraw it - which they wouldn't do. I must admit I was impressed that in 30k of total abuse I couldn't break the damn thing.
There is no instant fuel economy gauge in my V10 powered M5 Touring. However, you can access a digital one via the hidden menu of the iDrive. Makes for a scary reading, but then I discovered that it would not show a reading below 7mpg... Now that is really scary...
Once I emptied the tank in 80 miles while getting lost on a one way toll road in Germany
Once I emptied the tank in 80 miles while getting lost on a one way toll road in Germany
Gassing Station | General Gassing | Top of Page | What's New | My Stuff