[Raid]

Hello how's it going everyone? Hope you all had a nice weekend. I'm just a bit concerned about the MPG it showing me in my dashboard its showing me 31.8 MPG is that right I think that's too low any idea or suggestions how can I improve it plz and I don't drive that hard either as I always change the gear when it shows on the dashboard any help plz

[eye30]

What type of driving have you done recently, town, motorway, stop start etc?

Did you reset when filling up?

At start did you fill to brim then fill to brim again to show fuel used?

Is calculated MPG the same as on board computer or is there a difference?
If so, what was calculated?

[AlanHo]

Raid

You cannot assume the economy trip is accurate - none of my last 5 cars had an accurate trip recorder.

You also cannot assume that your odometer is accurate - my current car is 1.95% slow and my previous 4 cars were all inaccurate between 1.2% and 2.6% slow.
I check mine when on at least a 50 mile motorway journey by comparing the odo with the kilometer distance boards.  As you pass a kilometer board get your passenger to note the distance displayed and the odometer reading at the same time.  After travelling a long distance do the same for another distance board. It is then simple maths to determine the distance travelled according to the motorway boards (convert Kilometers to miles) and the distance given by the odometer. Express this as a percentage.

You new need to brim the car - and I do mean brim it until petrol is about to overspill the filler neck. This will take several minutes of patience. Write down the odometer reading and reset the economy trip to zero

When you next need petrol - brim the tank again right to the top. Again note the odometer reading, the amount of fuel added and the economy trip recorder reading.

Take the original odo reading from the second one - this gives the miles travelled on the last tank of fuel. Multiply this distance by the percentage inaccuracy of the odometer to get the actual miles travelled.

Convert the litres of fuel you have added to gallons. Now divide this into the actual distance travelled to get a dead accurate mpg.


You can now compare this with the economy trip reading to establish how accurate it is.

My previous car was a 1.6 litre petrol manual box KIA Venga - which is an aerodynamic brick compared with an i30. I averaged 42.17 mpg over a distance of 17,000 miles before I sold it.

My new car is a 1.6 litre petrol auto Venga which did 503 miles on its first tank of fuel and averaged 42.12 mpg.

Having said all that I should explain that I now drive for comfort and safety rather than speed.
I always accelerate gently and try to anticipate the traffic conditions at all times so I minimise the use of brakes. Whenever you use brakes - you have just wasted fuel - you should have taken your foot off the loud pedal earlier.
I cruise on A roads and motorways at between 55 and 65 mph - depending on mood and how busy the road is.
I don't carry any junk in the boot - extra weight hits fuel consumption.
My tyres are set at 36 psi - even though the book recommends 32 psi - another economy aid.
In a manual car I always use the highest gear the car is comfortable with. In an auto this is taken care of for you.
On a downhill run I usually let the car go as fast as gravity takes it (but watch out for speed cameras). I try not to use the brakes to kill the speed - the next hill climb will do that.
I don't buy supermarket fuel - Shell or BP standard 95 octane is my preference. I have tried 97 octane several times - but on every occasion the economy was the same or even worse than 95 octane. High octane fuel has never given me better mileage.


Have fun.....................


 

[Raid]

Raid

You cannot assume the economy trip is accurate - none of my last 5 cars had an accurate trip recorder.

You also cannot assume that your odometer is accurate - my current car is 1.95% slow and my previous 4 cars were all inaccurate between 1.2% and 2.6% slow.
I check mine when on at least a 50 mile motorway journey by comparing the odo with the kilometer distance boards.  As you pass a kilometer board get your passenger to note the distance displayed and the odometer reading at the same time.  After travelling a long distance do the same for another distance board. It is then simple maths to determine the distance travelled according to the motorway boards (convert Kilometers to miles) and the distance given by the odometer. Express this as a percentage.

You new need to brim the car - and I do mean brim it until petrol is about to overspill the filler neck. This will take several minutes of patience. Write down the odometer reading and reset the economy trip to zero

When you next need petrol - brim the tank again right to the top. Again note the odometer reading, the amount of fuel added and the economy trip recorder reading.

Take the original odo reading from the second one - this gives the miles travelled on the last tank of fuel. Multiply this distance by the percentage inaccuracy of the odometer to get the actual miles travelled.

Convert the litres of fuel you have added to gallons. Now divide this into the actual distance travelled to get a dead accurate mpg.


You can now compare this with the economy trip reading to establish how accurate it is.

My previous car was a 1.6 litre petrol manual box KIA Venga - which is an aerodynamic brick compared with an i30. I averaged 42.17 mpg over a distance of 17,000 miles before I sold it.

My new car is a 1.6 litre petrol auto Venga which did 503 miles on its first tank of fuel and averaged 42.12 mpg.

Having said all that I should explain that I now drive for comfort and safety rather than speed.
I always accelerate gently and try to anticipate the traffic conditions at all times so I minimise the use of brakes. Whenever you use brakes - you have just wasted fuel - you should have taken your foot off the loud pedal earlier.
I cruise on A roads and motorways at between 55 and 65 mph - depending on mood and how busy the road is.
I don't carry any junk in the boot - extra weight hits fuel consumption.
My tyres are set at 36 psi - even though the book recommends 32 psi - another economy aid.
In a manual car I always use the highest gear the car is comfortable with. In an auto this is taken care of for you.
On a downhill run I usually let the car go as fast as gravity takes it (but watch out for speed cameras). I try not to use the brakes to kill the speed - the next hill climb will do that.
I don't buy supermarket fuel - Shell or BP standard 95 octane is my preference. I have tried 97 octane several times - but on every occasion the economy was the same or even worse than 95 octane. High octane fuel has never given me better mileage.


Have fun.....................


 

That's a nice write up Alan thanks a lot for all the info and will definitely write them down next time I fill up the car but most of the time I don't fill the car up all I do just put 20 pound in it that will last me about a week as I don't drive everyday thanks alan

[Raid]

What type of driving have you done recently, town, motorway, stop start etc?

Did you reset when filling up?

At start did you fill to brim then fill to brim again to show fuel used?

Is calculated MPG the same as on board computer or is there a difference?
If so, what was calculated?

Recently mostly traffic start stop but I saw it shows 31.8 I was like what the heck that's not right so wanted to come n ask you guys what do u think if that's right but I will do what Alan said and since I bought the car I haven't reset the ECU do you think I should do that? Thanks a lot mate

[AlanHo]

Raid

If you seriously want to know an accurate mpg for your car - you have to brim it each time you refuel. It's the only way of knowing just how much fuel the car has used over a known distance.

Being a pedantic anorak I brim the car every time and enter the figures in a spreadsheet. Here is the spreadsheet for my previous manual Venga.

[Raid]

Will do next time I put fuel in the car and Starr calculating everything so that I can get a clear picture thanks Alan

[wbm00]

On my last three tanks of fuel I've got 39, 36 and 46 MPG.

I use Fuelly - Track and Compare your MPG to track MPG.

[Doggie 1]

Like Alan said, I always brim my tank when refuelling.
As far as the gear indicator goes, I tend not to follow its advice because it doesn't take into account the terrain and can tell me to change up a gear when clearly the engine would be labouring if I did (such as when going uphill, for example).
I prefer to listen to the engine and know from experience when to change up or down.
You will get to know your car and will know when it is in its torque band and then will instinctively "feel" how to drive economically.

[Raid]

On my last three tanks of fuel I've got 39, 36 and 46 MPG.

I use Fuelly - Track and Compare your MPG to track MPG.

Thanks mate will check it out

[Raid]

Like Alan said, I always brim my tank when refuelling.
As far as the gear indicator goes, I tend not to follow its advice because it doesn't take into account the terrain and can tell me to change up a gear when clearly the engine would be labouring if I did (such as when going uphill, for example).
I prefer to listen to the engine and know from experience when to change up or down.
You will get to know your car and will know when it is in its torque band and then will instinctively "feel" how to drive economically.

Thanks mate I always change the gear without looking at the dash but then I thought maybe I should change it when it shows there and u right maybe that's why I'm getting a low mpg because I'm following the car method lol thanks mate

[AlanHo]

The Fuelly system is not accurate as a spot check. It does not take account of the fact that if you do not brim the tank each time it cannot know how much fuel you have used since the last fill.

However - if you keep fuelly updated over a very long period the errors average out and you will get a reasonably accurate average mpg.

My method gives you accurate figures for each tank and the overall average since your records began.

It all depends on the accuracy you are looking for.

What irritates me is the mpg averages for various cars published by some magazines and Honest John. These rely on information provided by readers who either guess, rely on their trip recorders or calculate a figure from how many miles they do on a tank without regard to how full or empty the tank was at the start and end. When you look on motoring forums you will find all sorts of unbelievable economy claims by posters wearing rose tinted glasses.

[Surferdude]

I use a simple Excel spreadsheet.
As someone said above. Over time the figures will average out pretty much spot on.
And you don't have to worry about brimming it each time.
(I'm a lazy anorak.  )

My spreadsheet is now 5 years and 11½ months old and the "to date" figure is 8.17 litres/ 100 klms.

[crayman]

The spreadsheet system (using kilometres and litres) at each top up is the go. No need to totally fill as everything will average over time.
The other problem with the "brim" method is garage driveway slope which makes a massive difference to the actual fill capacity.
Forget the car's fantasy world estimates, they're hopeless and helped by the incorrect speedo reading.
Mr's 1.8 manual never shows more than 5L per 100, usually sits around 4.7 and ours is mostly 110 highway/freeway driving.   
Then fill at the bowser and the sums come out around 6L per 100.
This using the car's odometer, in real terms it's around 5% worse.
100 indicated is actually 96, 115 indicated is 110.
Even with all new tyres, you won't get a speeding ticket in this thing.

[John Reid]

Good words, AlanHo. I hope people take heed of them.
My 1.8L petrol Premium auto indicates 8.0 L/100km overall (around 35.5 mpg) but I also double check this by fill-up records (as you do), by GPS, and by knowledge of actual road survey distances. Amazingly, despite the fact manufacturers generally err well on the side of making themselves look good (the recent VW emissions furore, e.g.), GPS and actual fill calculations provide a figure of 8.13 L/100km (about 35.0 mpg), surprisingly close to the TFT display.
By the way, my tyre pressures are 250 kPa (near enough 36 psi), both safer and better for fuel consumption.
Thanks for worthy and helpful comment.