High Fuel Consumption

[trevman]

i just got 24mpg on my last tank,

60ltrs got me 325 miles....

gutted!!! :(

can the aircon really drink up that much of my fuel?

thats the only thing ive done differently from my last few tanks, where i was getting around 250miles from 35ltrs ~ 32mpg

:(

Yeh, the aircon seems to be very detrimental on most cars. It's not so bad if you always have the aircon on, but if you switch it on/off with the weather (as I do), you certainly notice the fuel dropping.

Of course none of this would be a problem if we weren't paying a fortune for fuel.

[Yonzie]

57 mpg!!!! What are you doing towing the IS from another car

Well... it can only be done at 30-35mph in 5th/6th gear with an extremely light foot. Takes a bit of concentration

[doog442]

I appear to have averaged about 29mpg from my first ...and possibly last.. tank

IS200 SE 45K on clock

Ive put my foot down when required....air con as required and a liberal use of 6th gear when cruising also mixture of town ,motorway and slow by pass traffic

[Rikos]

Why possibly your last?

Sorry just seen your post

[ivanovoitch]

Just had my first decent spin in the Lex. €6.00 a gallon. 200 mile round trip. Cost of petrol approx €30.00. That's nearly 40MPG!

[pob]

I've had my IS300 for a week now. Did a run from Sheffield to Blackpool (via Liverpool) over the weekend. Mostly motorway, but a fair few 30-40mph A-roads also.

From fill-up to fill-up I've calculated my MPG to be 27.2 - not bad for a 3 litre beast.

Cheers

Phil

[j_jazzy777]

How much will a poor geometry affect fuel consumption. Anyone know??

[Vyker]

How much will a poor geometry affect fuel consumption. Anyone know??

im going to take a sub par educated guess here and say that fixing the geo will reduce your mpg.

more of the tyre on the road means it has more grip, which i guess in turn means more effort to roll it.

i think hot weather has something to do with economy...

ive had mine for 4months now, and i was used to getting 400miles out of 60ltrs [light comes on for last 10ltrs], but the last 2 tank fulls, im getting only 320ish... ive lost nearly 20% in mpg.

odd really!

[stuie]

How much will a poor geometry affect fuel consumption. Anyone know??

im going to take a sub par educated guess here and say that fixing the geo will reduce your mpg.

more of the tyre on the road means it has more grip, which i guess in turn means more effort to roll it.

i think hot weather has something to do with economy...

ive had mine for 4months now, and i was used to getting 400miles out of 60ltrs [light comes on for last 10ltrs], but the last 2 tank fulls, im getting only 320ish... ive lost nearly 20% in mpg.

odd really!

Id say hotter temperature would lower fuel usage as the air is warmer and less dense in turn cousing you to use more fuel in winter

[trevman]

Id say hotter temperature would lower fuel usage as the air is warmer and less dense in turn cousing you to use more fuel in winter

Yep, that's why aircraft need a longer take off run in cold weather. The warmer air is more combustable and requires less fuel to ignite.

There is hundreds of things that will effect economy, but short of stripping half the car down, you're not really going to improve it drastically.

I was reading the JD Power customer satisfaction surveys from 2004/2005. Both years the IS finished top of it class, they note that the only downside to the IS was the high fuel consumption compared with other cars in the same class. (like BMW 3 series etc.)

[j_jazzy777]

Good news! I filled the car up with VPower and travelled up to Manchester. Ran the tank almost dry and got 326 miles out of it. By my calc-a-mul-ations thats 21.16 mpg! A damn sight better than the 14mpg I was getting right at the start.

I gotta say it is still heavy on the ol' wallet though- esp. since Vpower is now £1 a litre, and in some places (Manchester) its £1.03 a litre! It cost me £56 quid to Manc, and £60 to get back.

[trevman]

Check out this website for the cheapest fuel in your area: Petrol Prices

Also if you get an Asda credit card you get 2p per litre off at Asda pumps.

Witht that taken into account i'm currently paying 91.9p for unleaded.

[j_jazzy777]

Check out this website for the cheapest fuel in your area: Petrol Prices

Also if you get an Asda credit card you get 2p per litre off at Asda pumps.

Witht that taken into account i'm currently paying 91.9p for unleaded.

Cheers, but from what I've experienced with the Lex so far- it seems to have expensive taste. If I put in normal unleaded to the sum of £10 I can just about get my car out of my road before I run out. If I was to whack in a full tack it most likely would not get me to Manc. before needing to refuel.

[Vyker]

may be a silly suggestion, but have you check that your tank isnt leaking? pinhole dripping fuel?

[j_jazzy777]

may be a silly suggestion, but have you check that your tank isnt leaking? pinhole dripping fuel?

Mai nons... this is the first thing I checked when i noticed I was getting 14mpg.

Also, I'm not sure how this would be affected by using cheap unleaded as opposed to Vpower? Surely they would both leak the same? The point I was making is that with the latter I can travel a distance whereas with the former I might as well not bother starting the car, but I dont understand why the car is so picky.

[Mike_B]

How much will a poor geometry affect fuel consumption. Anyone know??

im going to take a sub par educated guess here and say that fixing the geo will reduce your mpg.

more of the tyre on the road means it has more grip, which i guess in turn means more effort to roll it.

i think hot weather has something to do with economy...

ive had mine for 4months now, and i was used to getting 400miles out of 60ltrs [light comes on for last 10ltrs], but the last 2 tank fulls, im getting only 320ish... ive lost nearly 20% in mpg.

I'd say the geo would be the other way round - correct geo will have the wheels rolling straighter, which will mean much less friction than dragging them sideways. Geo isn't just camber...

Warm air is less dense which means less fuel will be required to give the correct stoichiometric ratio, but as a result your engine will generate less power for a given throttle opening. Therefore you will need to use wider throttle openings to maintain the required acceleration. However - are you sure you're not just running the aircon more? Compressor pumps require a lot of effort to turn, sucking engine power away from driving the car and into cooling the interior. You can expect to use at least 10% more fuel with the aircon switched on in hot weather...

[j_jazzy777]

How much will a poor geometry affect fuel consumption. Anyone know??

im going to take a sub par educated guess here and say that fixing the geo will reduce your mpg.

more of the tyre on the road means it has more grip, which i guess in turn means more effort to roll it.

i think hot weather has something to do with economy...

ive had mine for 4months now, and i was used to getting 400miles out of 60ltrs [light comes on for last 10ltrs], but the last 2 tank fulls, im getting only 320ish... ive lost nearly 20% in mpg.

I'd say the geo would be the other way round - correct geo will have the wheels rolling straighter, which will mean much less friction than dragging them sideways. Geo isn't just camber...

Warm air is less dense which means less fuel will be required to give the correct stoichiometric ratio, but as a result your engine will generate less power for a given throttle opening. Therefore you will need to use wider throttle openings to maintain the required acceleration. However - are you sure you're not just running the aircon more? Compressor pumps require a lot of effort to turn, sucking engine power away from driving the car and into cooling the interior. You can expect to use at least 10% more fuel with the aircon switched on in hot weather...

Woah. Major science lesson here- most of which went straight over my head. One thing I do know is that the air con stays off for all but the most extreme conditions. My air con approach normally involves opening all the windows and the sunroof, and yes I do know this creates more drag (before anyone jumps in) :winky:

[stuie]

Just a thought could you all write down how old you car is how many miles its done and what sort of life its had mostly motorway etc and also when was it last serviced and was it a big or little service

mines an 05 plate has done 32K was serviced at 30K I dont know what sort of life it had but im guessing motorway and it know does the 5 miles commute to work and back

[j_jazzy777]

05 plate, 31k, serviced at all regular intervals and recently at 28k. Life? Not sure, but fairly certain that it has been used for a lot of business travel and a fair bit of motorway driving.

[Vyker]

T plate, 92k, serviced at all intervals bar one [80k]

last serviced at 91k costing £600, including belt.

owner 1: motorway miles

owner 2: heavy city usage.

owner 3: me, motorway miles

[Lee.h]

Hi, my car has had a full motorway life. Its now on 117k. Full Lex sevice history.

I have just drove from home (Cornwall) to Essex and back. Full tank of fuel did 400 miles and the fuel light came on. That works out to be 28 mpg ish.

I am happy with that. :)

Oh and its green if that makes a difference.

[stuie]

I was thinking more that the cars that suffer with lower fuel consumption also seem to be younger and have less miles on them

[Lee.h]

I was thinking more that the cars that suffer with lower fuel consumption also seem to be younger and have less miles on them

Its almost as if they ripen with age :D

[j_jazzy777]

That's interesting....and scary cos I'm getting to the stage where I dream of big L badges swooping down and sucking the blood from my arms and legs!!

Darned Lampires!! They're really after my wallet.

[trevman]

I've just accurately calculated my fuel consumption.

I spent £41 which is 43.66 litres and got 412 miles, if I did the sums right that equates to 43mpg (UK gallon)

That's with a mixture of motorway miles and town driving, quite a few cold starts with short journeys, an MOT, aircon on and off as required, and I lent the car to my dad (different style of driving) for 60 miles.

Better than I thought.