Discussion
Well for the first time since buying the car i've worked out the mpg. I brimmed the tank this afternoon and went for a reasonably enthusiastic 50 mile 
across Norfolk. Went back to petrol station and brimmed the tank again. It took 10.05 litres which by my maths works out at 22.6 mpg. How much can your mpg tell you about how your donkey is performing? I still think it's rich when cold despite changing the coolant temp sensor but I assume once warm it leans up?
What you lot reckon?
Jimbo
across Norfolk. Went back to petrol station and brimmed the tank again. It took 10.05 litres which by my maths works out at 22.6 mpg. How much can your mpg tell you about how your donkey is performing? I still think it's rich when cold despite changing the coolant temp sensor but I assume once warm it leans up? What you lot reckon?
Jimbo
I had a run down to that London a few weeks ago, 800 mostly motorway miles, there and back at a steady pace. The car averaged about 26 mpg. I thought it was running rich but this seems to suggest it isn't.
If your run out was a bit sprited then I would expect about what you got. Probably get the same in mine pottering around. A bit different to when I first got it when I think it was doing around 12-15 mpg
If your run out was a bit sprited then I would expect about what you got. Probably get the same in mine pottering around. A bit different to when I first got it when I think it was doing around 12-15 mpg
It's all a bit subjective, but if I drive my 2 ton 3.5, manual, "reasonably enthusiastically" I would expect to get between 24 and 26 mpg. I also know the efi system is running a tad on the lean side, but it always has, as most of them seem to.
With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
honestjohntoo said:
It's all a bit subjective, but if I drive my 2 ton 3.5, manual, "reasonably enthusiastically" I would expect to get between 24 and 26 mpg. I also know the efi system is running a tad on the lean side, but it always has, as most of them seem to.
With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
Indeed. No chance this wek mind as i'm at RAF Wattisham all week then it's the fest on Saturday. After that I fully intend to get stuck in. Will prob check plugs and change as a matter of course anyway.With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
JMF894 said:
That's good to hear. Sounds like the old girl is running reasonably well then. However if you took that rear spoiler off yours you'd get nearer 40mpg for sure 
On F1 cars, they have wing adjusters that they alter for different tracks, or even mid race and now they have open/shut rear wings. Food for thought me thinks
I used to regularly get 18mpg from mine - probably still do, but I stopped worrying about it years ago 
I think a typical motorway-speeds cruise (usually only to the 'Fest!) sees low to mid 20's. I'm expecting an increase over recent consumption once I rebuild the sticking brake caliper
I think a typical motorway-speeds cruise (usually only to the 'Fest!) sees low to mid 20's. I'm expecting an increase over recent consumption once I rebuild the sticking brake caliper
My 400 that I owned a few year years ago had one good motorway run up to Derbyshire when my parents retired. I went up to help them move house and it was also a great opportunity to drive some of the excellent Peak District roads from when I was a yoof. The motorway run saw 25mpg i recall from a steady 70-80mph.
honestjohntoo said:
It's all a bit subjective, but if I drive my 2 ton 3.5, manual, "reasonably enthusiastically" I would expect to get between 24 and 26 mpg. I also know the efi system is running a tad on the lean side, but it always has, as most of them seem to.
With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
I had a Vanden Plas EFi with the same engine as a standard 350, it had a 3 speed auto box and a lot more weight to carry.With your lightweight and a 4.5 you might expect similar in and around the flatlands, but you think its running rich.
That in itself would be sufficient to account for the difference. At the simplest level I would not rely on perceived mpg to identify a performance issue, after all you could have a tank brimming problem or a fuel leak.
In your case a check on the condition of two spark plugs, one from each bank. would be a good start and report back. Time to do that 15 point health check, methinks?
The VDP had a real-time fuel-consumption gauge, generally reading in the range 15-18 mpg.
Going up a shallow hill with four capatious blokes on board at full chat I once saw 0.7 mpg on the gauge - so you were lucky!
I think that the mpg figures can tell you more about your driving habits (left foot heaviness) than the state of the vehicle. The best check is comparison of a long journey on a UK motorway (where you are more limited by other traffic than your enthusiasm) and you are in top gear most of the time.
A great gauge of fuel richness is the colour of the plugs after a longish run like this. They should be the colour of a McVities digestive biscuit (not chocolate).
Russ
KelWedge said:
Hi Jim
The old 4.0 did about 14 Normal or about 21 on a long run, the new 4.6 hits all of 16.5 or 22.5 long run, lets see who runs out first next Sat.
I'll also be very interested to see how mine performs next to yours too Kelvin. Do you know how many horses yours is giving now?The old 4.0 did about 14 Normal or about 21 on a long run, the new 4.6 hits all of 16.5 or 22.5 long run, lets see who runs out first next Sat.
I have averaged mine out at several times and get about 25mpg whenever I do a run
but brimmed it last week and had a very spirited run (2 mile runway etc) and still got 18mpg
Hope to get nearer to 25 for the run down to Ettington
but depends how much I have to keep waiting for Dixiebabes!!!! Ha Ha
HTH
Trickie
but brimmed it last week and had a very spirited run (2 mile runway etc) and still got 18mpg
Hope to get nearer to 25 for the run down to Ettington
but depends how much I have to keep waiting for Dixiebabes!!!! Ha Ha
HTH
Trickie
JMF894 said:
My 400 that I owned a few year years ago had one good motorway run up to Derbyshire when my parents retired. I went up to help them move house and it was also a great opportunity to drive some of the excellent Peak District roads from when I was a yoof. The motorway run saw 25mpg i recall from a steady 70-80mph.
How much furniture were carrying in the 400 Jim?
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