petrol prices

jezzer

when the price of petrol was circa 132.9 per litre i would put 40 euro in the tank and get exactly 4 days out of it to and from work....recently there has been a significant drop in price and on sunday i filled up at a service station where the price was 123.9 (cheapest around), i thought great, this might get me out to 5 days and put 40 euro in as normal.....however i didnt even manage to get a fourth day out of it....obviously this doesnt make sense and i heard previously about retailers being able to rig their pumps, is this true? this must be the case here, although i cant obviously confirm that i think the retailer should be investigated, who could i report this to? the retailer in question was selling petrol at 123.9 when the next lowest anywhere was at 125.9....

MuppetCheck

There may not have been the exact same amount in the tank.

The colder weather increases consumption.

Fuel could indeed be crap.

You might have driven it harder.


There's loads of possible explanations, the only way to know for sure is to do brim to brim calculations.

stimpson

The difference is about 7% yet you think your car should go 20% further?

advertsfox

There's only 9c difference in the liter, your €40 initially got you 30 liters, now it's getting you 32.2 liters so without knowing how much was in the tank at first, how hard you drove the car of what the driving conditions were like (traffic, motorway) and the exact odometer readings - there could be a dozen reasons. The €40 price isn't the measure of distance, your MPG or L/100KM against the fuel in your tank is.

jezzer

MuppetCheck wrote: »

There may not have been the exact same amount in the tank.

The colder weather increases consumption.

Fuel could indeed be crap.

You might have driven it harder.


There's loads of possible explanations, the only way to know for sure is to do brim to brim calculations.

I always fill when the light comes on, i do the exact same distance at the same speeds ever day for the 4 days, however yes good point re the cold weather however, i would expect to get at least the same distance out of it not less....

jezzer

stimpson wrote: »

The difference is about 7% yet you think your car should go 20% further?

well i got at least 7% less, how would you figure that?

jezzer

advertsfox wrote: »

There's only 9c difference in the liter, your €40 initially got you 30 liters, now it's getting you 32.2 liters so without knowing how much was in the tank at first, how hard you drove the car of what the driving conditions were like (traffic, motorway) and the exact odometer readings - there could be a dozen reasons. The €40 price isn't the measure of distance, your MPG or L/100KM against the fuel in your tank is.

understandable, but i know my car and with an extra 2.2 ltrs you would expect to get at least the same distance out of it....not less.....

Alanstrainor

jezzer wrote: »

I always fill when the light comes on, i do the exact same distance at the same speeds ever day for the 4 days, however yes good point re the cold weather however, i would expect to get at least the same distance out of it not less....

I think in reality you need to actually record the amount of petrol used. Fill it, reset your trip computer, and then when you fill again record the litres you put in and also the amount of kms covered.

The light wont come on at the same time every time, it's quite an inaccurate measurement really...

jezzer

Alanstrainor wrote: »

I think in reality you need to actually record the amount of petrol used. Fill it, reset your trip computer, and then when you fill again record the litres you put in and also the amount of kms covered.

The light wont come on at the same time every time, it's quite an inaccurate measurement really...

true but i really cant understand how i got less distance out of lower prices petrol

advertsfox

jezzer wrote: »

understandable, but i know my car and with an extra 2.2 ltrs you would expect to get at least the same distance out of it....not less.....

I know my car too but no two journeys are the same. What doesn't lie is maths and figures.

Let's do some comparisons and say you drove a bit harder (not on purpose but by weather and driving conditions) and your MPG went up:

€40 got you 30.0 liters driving at 7.5 L/100KM (400KM for the cost)
€40 got you 32.2 liters driving at 8.0 L/100LM (400KM for the cost)

7.5L compared to 8L/100KM is only a difference of 3MPG, a figure than can fluctuate greatly (+- a value of 5 easily). My own car averages between 7.5 and 8.5 L/100KM.

Next time, add €40 as soon as your petrol light comes on and reset the odometer. Make note of the value it's at as soon as it comes on again and repeat at least 5 times.

Toyotafanboi

jezzer wrote: »

well i got at least 7% less, how would you figure that?

Because you are measuring in money.

The only true measurement is brim to brim. If you are just putting petrol in, not brimming and then putting more in, you don't know the exact quantities you have got pre and post fill up. 3 or 4 liters can easily be lost in translation as dashboard gauges aren't all that accurate.

jezzer

i will test this out but i still think the petrol station were up to funny business...

Starscream25

The colder weather will definitly knock a Good few miles off your gallon.

Toyotafanboi

jezzer wrote: »

i will test this out but i still think the petrol station were up to funny business...

Given the repercussions involved, i doubt it would be worth their while.

Fill your tank until it's full on a sunday night and reset the odometer, do your weeks driving, fill your tank again the following sunday, then you have an exact miles covered and liters used value.

Do this over a month or two and keep a record of it to get a true picture.

jezzer

thanks guys, i will do this toyotafanboi, plus yes, the cold weather could have been the issue, we will know soon, i'd just hate to think i along with others were being ripped off

dmc17

jezzer wrote: »

well i got at least 7% less, how would you figure that?

You forget to release the handbrake!

dmc17

I can't say I've noticed a whole load of difference myself, even since it came down from the 1.50 - 1.60 mark but I suppose it's gradual so I've probably adjusted to it or else the car is getting worse! Anyway, lets just hope it keeps going downwards and not up.

Slanty

How does the colder weather make the car drink more juice? Colder air is better for the engine than warm dense air.

If it was raining on a couple of those journeys then you may notice a difference but not that much

jimgoose

Slanty wrote: »

How does the colder weather make the car drink more juice? Colder air is better for the engine than warm dense air...

Cold weather is nature's supercharger. Cold air is denser, modern MAF sensors detect this and inject more fuel to maintain stoichiometric. "Better" is not necessarily more economical.

Chris_Heilong

Slanty wrote: »

How does the colder weather make the car drink more juice? Colder air is better for the engine than warm dense air.

If it was raining on a couple of those journeys then you may notice a difference but not that much

Maybe warm air conditioning on all the time to combat the cold?

advertsfox

Slanty wrote: »

How does the colder weather make the car drink more juice? Colder air is better for the engine than warm dense air.

If it was raining on a couple of those journeys then you may notice a difference but not that much

Why is winter fuel economy lower?

Cold weather and winter driving might influence your car performance in a number of ways:
- Battery performance suffers in cold weather and it is difficult for the alternator to keep your vehicle’s battery charged. This affects hybrid vehicles as well.
- It takes more time for the engine to reach its fuel efficient temperature than in warmer weather and this is especially valid for short trips, because fuel temperature is low for the entire duration of the trip.
- Defrosters for windscreen, heating, and heated seats consume extra power.
- Cold air is denser and increases aerodynamic drag on your vehicle.
- Your car idles while warming up which decreases your vehicle’s fuel economy.
- Cold engine oil and other fluids increases engine and transmission friction.
- In severe winter weather, four-wheel drive and low driving speeds, necessary for safety reasons, also influence fuel economy.

http://www.transpoco.com/blog/2014/11/20/fuel-economy-winter-weather/

Toyotafanboi

dmc17 wrote: »

I can't say I've noticed a whole load of difference myself, even since it came down from the 1.50 - 1.60 mark but I suppose it's gradual so I've probably adjusted to it or else the car is getting worse! Anyway, lets just hope it keeps going downwards and not up.

feels pretty good. i had one of those 10c off per litre in tescos vouchers, making petrol cost 1.19. just filled the corolla from a quarter tank to full for €43. that's sound, not so long ago that would cost around €55. that's a tenner back to me

xabi

jezzer wrote: »

thanks guys, i will do this toyotafanboi, plus yes, the cold weather could have been the issue, we will know soon, i'd just hate to think i along with others were being ripped off

Go to the same place and buy 1 or 2 litres in a petrol can, youll know then - i doubt they have fiddled the pumps.

NIMAN

Latest price I drove past this morning,

Diesel 117.9
Unleaded 124.9

and 30% on sterling. Sweet!

Toyotafanboi

advertsfox wrote: »

Why is winter fuel economy lower?

Cold weather and winter driving might influence your car performance in a number of ways:

- Battery performance suffers in cold weather and it is difficult for the alternator to keep your vehicle’s battery charged. This affects hybrid vehicles as well.

i doubt it is "difficult". it's also not as if the system can be "sped up" to increase load during the cold, it's charged from a fixed pulley all year round.

- It takes more time for the engine to reach its fuel efficient temperature than in warmer weather and this is especially valid for short trips, because fuel temperature is low for the entire duration of the trip.

granted it takes an extra minute or two to reach operating temperature which is a little more consuming, but "fuel temperature being low"? seriously? does my fuel get heated in the fuel tank if the trip is longer? lol.

- Defrosters for windscreen, heating, and heated seats consume extra power.

extra electrical power. and the source of electricity? the same fixed pulley that is rotating at the same speed as if you had all these items switched off.

- Cold air is denser and increases aerodynamic drag on your vehicle.

NASA might take this into consideration with the space shuttle, but the difference made to a fiesta going to the shops i'd say is immeasurably small.

- Your car idles while warming up which decreases your vehicle’s fuel economy.

we don't idle our cars up to temperature do we? this disagree's with all manufacturers guidelines which tell you to drive your car up to temperature. but my that same rational, "using your car instead of walking decreases fuel economy too". reading this forum too, if you idle your car without you in it, it'd be robbed.

- Cold engine oil and other fluids increases engine and transmission friction.

this is only relevant up to operating temperature, which has been distanced by 2-3 minutes, hardly massive.

- In severe winter weather, four-wheel drive and low driving speeds, necessary for safety reasons, also influence fuel economy.
really, driving for longer uses more fuel? never, really?

i know you didn't write that yourself, but jaysus it's drivel.

the only thing worth mentioning, as above is the more dense air requiring more fuel in an attempt to stay stoich. this might have some bearing.

jimgoose

Toyotafanboi wrote: »

i know you didn't write that yourself, but jaysus it's drivel.

the only thing worth mentioning, as above is the more dense air requiring more fuel in an attempt to stay stoich. this might have some bearing.

Share of crap there, but they will stay on cold enrichment maps for a while longer in very cold weather, and the electrical load of various heating appliances - rear screen, etc. - does have a small effect.