Fuel Consumption Characteristics

[ehoe]

Just curious, does anyone notice that the FC from full tank (80L) to midway mark (40L) is a lot slower than from midway mark (40L) to empty (0L). Dunno if its just me but once the fuel gauge reaches half way mark FC seems to be a lot faster and it reaches empty real quick in comparison to from full tank to half way. I think I'm getting roughly around 230 - 260km on the first half tank of gas in city driving but once reaching half tank, it goes to empty real quick. Sometimes getting less than 200km on the remaining half tank of gas. :blink: Anyone else notice this?. Just curious....

 

[mafia]

i get the same problem too...

 

[Lionel_Koh]

Me too....I think it's common for E34...

 

[iCe]

me too,when i was driving eg9 honda civic some times ago.,

 

[xtracooljustin]

not only E34 but lot of other cars... u c... the gauge for fuel is not a linear kind of scale... i dunno how to put it in proper english. but a lot of other cars r like that too, even my toyota and E28.

u c, the fuel tank is not exactly square/rectangular in shape, n i think the fuel inside is measured by the level of fuel inside, n not the amount. the fuel tank is probably in an irregular form mayb designed to b bigger at da top n smaller at da bottom.

So the gauge doesnt really give an accurate indication of how much fuel is left, 50% shown on da gauge doesn't neccesarily mean 50% fuel left in tank, it is much less.

just my 2 kupang

 

[teejay]

dont forget when you are filling in to top up....

is it when you hit the red lights? or when the tank is really really empty? dont forget the red light means you about 10 lits of fuel ( just guessing for the E34, E30 has abt 8 lits, someone correct me if im wrong!)

so its possibly correct that the second half( abt 30 lits ) would use up pretty fast compared with the first half ( 40 lits )

or you could try something really daring, fill up a spare petrol tank,( this is used when you run out of petrol) then drive around till your fuel runs out, then you actually see if the second half uses as much petrol as the first, my guess the second half will use less petrol i.e. more mileage, compared with the first half, coz more consumption due to carrying the extra fuel around town......

xtracoolman,
fuel gauge is calibrated to the signal sent by the sending sensor to accurately measure the amount of fuel in tank, this info is also used by the OBC to calculate fuel consumption,how many more km/miles left before fuel tank goes empty, trip analysis-requires the OBC module, etc etc

 

[xtracooljustin]

ah... thanks for enlightening me TJ

 

[teejay]

Originally posted by xtracooljustin@Jul 25 2005, 03:14 AM
ah... thanks for enlightening me TJ

no worries dude.....

and yes you are correct about the uneven shape of the tank, but the sending unit sends whatever it measures, so its up to the gauge to decipher the signals, its both a combo of logarithms, exponential and linear equats........

i tried measuring the various signals at various levels, and it didn't make sense, coz i tot it was a linear measure...... :blink:

the red light that comes on for reserve is at a certain level and at a certain resistance, and that's set and very much accurate coz there's not much left........

it's also not recommended that the fuel pump is run too long without the fuel around it, especially those with in-tank, coz it will heat up easily and its life will be very much shorten

 

[tongsatriani]

Well, I pumped RM50 (32++ litres) when it reached "R" when warning light is lighting. Got pass just slightly 40. Managed to go 310km before refueling at warning stage. All this in city drive.

 

[535i]

Originally posted by ehoe@Jul 23 2005, 11:40 PM
Just curious, does anyone notice that the FC from full tank (80L) to midway mark (40L) is a lot slower than from midway mark (40L) to empty (0L). Dunno if its just me but once the fuel gauge reaches half way mark FC seems to be a lot faster and it reaches empty real quick in comparison to from full tank to half way.

I think I'm getting roughly around 230 - 260km on the first half tank of gas in city driving but once reaching half tank, it goes to empty real quick. Sometimes getting less than 200km on the remaining half tank of gas. :blink:

Anyone else notice this?. Just curious....

Same here ..

I get circa 200 miles (320km) for RM 55.00 (new price maa ..)
That will be half tank reading ...

Full tank = RM 120 !!!!

 

[amizana]

Originally posted by tongsatriani@Jul 25 2005, 02:32 PM
Well, I pumped RM50 (32++ litres) when it reached "R" when warning light is lighting. Got pass just slightly 40. Managed to go 310km before refueling at warning stage. All this in city drive.

So, in this case, if we want to save RM, the best thing to do is to
fill in half tank rather than full tank.

Am I correct? :dunno:

 

[teejay]

i did try half, 3/4 and full tank fills

got better mileage at half fill, almost the same, but slight lower at 3/4 tank, but for me half tank is about 25 lits, plus i drive alot.....
full tank, rugi about 10-15 kms per full fill compared to half tank.

basically would go for in between half and 3/4, but then again mine is an E30, for other heavier models and cc can try and do the same , just measure consumption for the amount of fuel that's in and gauge which is the best amount to fill in.....

 

[Lionel_Koh]

Originally posted by cyne@Jul 25 2005, 11:20 PM
What are the normal fuel consumption of a full tank ? Anybody recorded these before ?

Pls refer Fuel Consumption for the infor......

 

[xtracooljustin]

if ur car at full tank, fuel consumption will slightly suffer also... cos ur carrying the weight of the unused fuel around...