Miles Per Gallon

[George Elliott]

I agree, there is a cooler weather benefit for all models in cooler (more dense) air, and better intercooler efficiency on turbo's. also agree the headlights up cost 1mpg, and the electrical load has an effect in winter, I reckon Cup versus Flag mirrors cost 0.5mpg. (try holding your hand square on to the air flow at 50mph, the resistance is incredible)

When I test drove my SPS 2.5T, I wanted to be sure of the temperament of the car, and asked Simon for a 2 hour 100 mile test run covering Town, Country, and Motorway miles. No problem, I think he was quite pleased with hindsight, so I brimmed the car with Shell at the start and finish, and it returned 27.8mpg.

My then current 951 returned 25mpg overall in similar use. The SPS car is torquey-er, less laggy, nicer to drive, quicker and more economical.

Tyre pressure, 30psi versus 36psi is also relevant

George

944t

 

[944Turbo]

ORIGINAL: Jonny944CS

(I'm interested to see how the Nissan Leaf's range is affected by a harsh winter),

I fancied getting a leaf and putting the biggest noisiest generator I could find in the boot (jet turbine maybe) I think as it is for power generation not motive power it could run on duty free fuel and It would annoy the greens especially with lots of noise smoke and maybe flames.
The 25k purchase price put me off though! maybe when they are under 1k

 

[Fat Albert]

funny to see my old post saying I was getting 275 miles to a tankful, I got 435 yesterday and I had only done 10 miles or so with the light on, so 450+ was easily attainable. I didn't drive particularly economically on Wednesday either

 

[simdel1]

ORIGINAL: 944Turbo

ORIGINAL: Jonny944CS

(I'm interested to see how the Nissan Leaf's range is affected by a harsh winter),

I fancied getting a leaf and putting the biggest noisiest generator I could find in the boot (jet turbine maybe) I think as it is for power generation not motive power it could run on duty free fuel and It would annoy the greens especially with lots of noise smoke and maybe flames.
The 25k purchase price put me off though! maybe when they are under 1k

[]

You need to find an old milk float. They must be pretty cheap by now [8D]

 

[Jonny944CS]

Cooler, denser air will increase fuel consumption, depending on how you drive. More air needs more fuel, there is a temperature sensor in the AFM.

Good point about the AFM temperature sensor. Therefore with air temp as the only variable ( i.e. a warm engine and constant speed), fuel consumption should be the same. You'll just be using slightly less throttle.

Or have I missed something?

 

[Jonny944CS]

ORIGINAL: simdel1

ORIGINAL: 944Turbo

ORIGINAL: Jonny944CS

(I'm interested to see how the Nissan Leaf's range is affected by a harsh winter),

I fancied getting a leaf and putting the biggest noisiest generator I could find in the boot (jet turbine maybe) I think as it is for power generation not motive power it could run on duty free fuel and It would annoy the greens especially with lots of noise smoke and maybe flames.
The 25k purchase price put me off though! maybe when they are under 1k

[]
You need to find an old milk float. They must be pretty cheap by now [8D]

[]

I think the Leaf is a fantastic piece of engineering. I just struggle to see it as a solution.
- Call me old fashioned, but if you want to get around a city - walk or use a push bike!
- If you want to drive long distances, you'll have to wait XXXX number of years for battery tech and Nuclear Power Station construction to catch up.
Rant over. [&o]

I much prefer the concept and thinking behind these. [8D]

 

[VanhireBoys]

My MPG on the urban cycle was horrid .. Maybe 18mpg.... Since I got the car CO set up she is averaging 30+ MPG .. Fare play to Dave !

I came from Cirencester to Galway on the one tank which is 428 miles... Going along nicely as well ! Id say I could push 500 out of it !

My fuel guage is a bit strange as it was just in the red and I filled it .. It took 65 litres.. So I figure there was still 15 litres in the tank !
I never ran out of fuel in the 11 years I have it ... Always wondered why......! []

As Mike so rightly put it .. Dont worry about MPG .. Just enjoy the run !

 

[tref]

I don't worry about MPG, unless it drops dramatically - then I take it as early warning that something is wrong/time to give it a service... which, strangely, always seems to be autumn, and never has a dramatic effect!

It never ceases to amuse me that I get better MPG towing a little box trailer than when travelling solo! I guess that suggests I usually just enjoy it

 

[simdel1]

ORIGINAL: Jonny944CS


[]

I think the Leaf is a fantastic piece of engineering. I just struggle to see it as a solution.
- Call me old fashioned, but if you want to get around a city - walk or use a push bike!
- If you want to drive long distances, you'll have to wait XXXX number of years for battery tech and Nuclear Power Station construction to catch up.
Rant over. [&o]

I much prefer the concept and thinking behind these. [8D]

Agreed. Plug-in electric cars are pointless unless they are part of a fully integrated renewable energy infrastructure.

That VW looks cool! []

 

[pendrifter]

Have had my '86 944[2.4] for about 20 months now and have always calculated mpg at every fillup. Only do about 5000 miles a year all around the lanes of Cornwall except a couple of trips to London a year. Mpg has always been 18-20mpg.
Always starts first time from cold but on a couple occasions when engine has been running, it refused to start unless left for an hour or so!
Happened a few weeks ago. Returned later - start first time. Googled problem and found much information on the DME relay. Found it on the car, and pulled it out which was very easy. Put back in but decided later to buy a new one. Wanted to check part number. This time it was considerably harder to pull out, but out it came. New one arrived but haven't replaced yet. As usual filled up for the London trip; calculated and found 25mpg! [Thought this must be a mistake].
Did the London trip [fairly rapidly I have to say!] and on the way back filled up, fuel light not showing but decided to be safe. Had done 345 miles which worked out at 26.5mpg! Far better than ever before.
Can anyone explain. Could it have been the relay not making positive contact.
Be interesting when the next fillup comes around.

 

[sulzeruk]

I would be checking the DME temperature sender as 25 to the gallon on a Lux is pretty rich. See if you can find a friendly garage to check the CO,
Alasdair

 

[Lowtimer]

I agree. It ought to be doing 30 really, on motorway use, unless you are really hooning around.

 

[Paul 290T]

Hi,

My 1986 turbo varies between 18mpg when in stop start city traffic and gets to 26mpg on a mix of dual carriageway and A and B roads.

 

[Lowtimer]

Yes, it has an effect and the shorter your runs, the more the lower ambient temperature affects your fuel consumption (because you spend more time in warm-up enrichment). On a long run the effect is negligible because once the engine is up to temperature the thermostat keeps it there regardless of external air temperature.

Although on a very cold, high pressure day the air is much denser than on a hot summer day so you will actually get increased drag for a given speed through the air, and that could be another factor on long winter runs.

 

[Mike_Pollock]

Cold air is also a lot more viscous than warm, which is the cause of the increased drag!

 

[pendrifter]

Update
Filled up today at local asda [done 350 miles and fuel light still wasn't on!]. Put 70 litres in. Calculated at 26mpg. About 150 miles at speed [got speed ticket this morning to prove it![] ]the rest around locally North Cornwall lanes! What thoughts please, do I need to get something checked?
Thanks for help so far.

 

[tref]

That isn't necessarily so bad at this time of year - really depennds upon what sort of speeds you are doing, how much is stop/start motoring around the little lanes etc... One tankful isn't a trend - it has taken best part of 100k miles over four years for me to be able to see the summer/winter trend. I easily see plus/minus 3mpg on a tankful in normal use, and suspect that is variations in quite how full full is each time I fill up - that and quality of the fuel which is going in.