Gashde

A question that I've always been curious about, that is wither re-fueling a full tank of gas is or not the most efficient level.

I've been told that fueling 3/4 of the car is the most optimum, this being that the car carries more weight at full-tank, where in return more fuel is being consumed because of the additional power required to get the car moving.

I drive a C220, and personally I noticed that the 1st quarter of my fuel gauge tends to be used much more quickly then from 3/4 and 1/2, I suppose driving habits may vary slightly, however I've always manage to maintain an overall of 6.5L/100km.

Are these road cars designed to be most fuel-weight efficient at full tank of gas?

Does anyone have thoughts on this??

vic viper

Do the math, diesel weighs 0,8kg per litre, that means that a quarter tank of diesel weighs around 14kg.s, I highly doubt that only 14kg.s would increase fuel consumption in a noticeable way.

ilumunus

Okay, maybe if you're driving a '79 F250 with a 90 gallon tank then maybe yes you will lose mileage (btw you would probably get like 2mpg if you had this setup). But on a 15-20 gallon tank I don't think it should make a difference. Maybe like - .2 mpg difference.

Glyn M Ruck

Fuel weight has a small but negligible effect. Fuel gauges are not 100% linear on these cars. Realtime fuel consumption once at operating temperature is a lot more meaningful than the gauge.