Fuel usage question

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18-02-2007, 07:22 PM
Breezy

Fuel usage question

Hey guys, i have notice that if all through out the week it has been hot weather i get at least 450+km a tank. But in cold weather i get 350km a tank, so my question is why do i get more k's when its hot, and can i do something to get the same amount of k's a tank in cold weather?
18-02-2007, 07:46 PM
blk_shadow

Quote:

Originally Posted by Breezy

Hey guys, i have notice that if all through out the week it has been hot weather i get at least 450+km a tank. But in cold weather i get 350km a tank, so my question is why do i get more k's when its hot, and can i do something to get the same amount of k's a tank in cold weather?

I notice that too.

my guess will be something about the heat that built up around the engine so high, that it will give an extra load for the engine
and that extra load = more fuel. plus air cond. usage
19-02-2007, 07:53 AM
blk_shadow

yeah, and also cos its evaporates faster on the fuel tank
19-02-2007, 08:36 AM
aaronng

He's complaining that he gets worse fuel consumption when cold.

It's because cold air is denser and more fuel is put in so that the combustion doesn't run lean.
19-02-2007, 09:15 AM
EfiOz

Hot weather brings with it a fairly drastic drop in air density. So if we have a lower air density, then we have less oxygen per litre of air the engine ingests. Therefore we need LESS fuel to go with it.

This is also the reason that cars make more power with cold air around and less in really hot conditions. If you do the math you'd be a little shocked by how much power you drop between 25C and 40C intake temp..........
19-02-2007, 06:44 PM
Breezy

Quote:

Originally Posted by aaronng

He's complaining that he gets worse fuel consumption when cold.

It's because cold air is denser and more fuel is put in so that the combustion doesn't run lean.

So i'm running rich?
19-02-2007, 06:58 PM
aaronng

Quote:

Originally Posted by Breezy

So i'm running rich?

Not really. Cold air is denser, so the fuel maps inject more fuel at lower temperature.
20-02-2007, 07:46 PM
Breezy

Quote:

Originally Posted by claymore

You also have bought your fuel when its in the underground tank at a constant temperature of let's guess 17 degrees C. When it gets pumped into your cars fuel tank to the full mark and it's colder outside than the 17 degrees the fuel was at in the underground tank as soon as you drive away the fuel starts to contract from the cold so even if you lived right next to the station by the next morning you now have less fuel in the tank because it has contracted due to the colder temperature so your km/fuel use calculations are off from the start.

ok, so you mean that out of say 38 liters of petrol i get 450km out of it in 1 week, but within say 2 weeks with 38 liters i will not get as much k's?
20-02-2007, 08:18 PM
Limbo

does your water temp move below 1/2 way? maybe your car is running too cold, may need a new thermostat. It shouldn't make that much diff in kms cos your car should still get up to operating temp, unless your driving in snowy weather?
21-02-2007, 07:50 PM
Breezy

Quote:

Originally Posted by Limbo

does your water temp move below 1/2 way? maybe your car is running too cold, may need a new thermostat. It shouldn't make that much diff in kms cos your car should still get up to operating temp, unless your driving in snowy weather?

Nope, my temp is on halfway all tha time. Yea tryin to figure out why there is a big diff, i was suprised to even reach 450kms. Normally i would only get 350kms in cold/normal weather. Hope the hot weather stay for a bit longer this year.:)