Help with mileage figures

micks_address

Hi Folks,

I'm trying to figure out mileage costs. I'm currently driving a 2009 2.2 litre diesel accord and love it.. but I reckon on my commute(north dublin to citywest) i'm possibly getting about 40 mpg when traffic and everything else is considered.. bit of stop/starting on the motorway and even when I avoid the motorway there are lots of lights/junctions on the alternative roads - even if im driving more often that being stuck in traffic.

If I were driving a car that got me 60 mpg versus 40mpg - and doing 350km per week how much would I save on fuel costs roughly over 12 months? I know I should be able to work this out but my maths aint great!

Also just in relation to my journey. I can stick to the m1/m50 and the commute takes about 45 minutes on average but as I said it can be slow start/stop on the m50 or I can take back roads and avoid the motorway altogether and it takes about 55 minutes. For an extra 10 minutes driving what would you do? Would you rather be moving all the time, or sitting in traffic? And which would be more economical on fuel?

Cheers,
Mick

TBi

40MPG? I get that out of my petrol mini. I'd expect a diesel to be getting 50+.

I do about 40k km per year with a fuel bill of about €5k. Going from 40MPG to 60MPG would save me about €1,800 per year. If you could get 80MPG you'd half your fuel bill.

Try a smaller diesel (since you travel 100kph or lower) or a Prius (if you can handle the image)?

jimgoose

Just got the most ferocious flashback to the Inter Cert there!

CiniO

micks_address wrote: »

Hi Folks,

I'm trying to figure out mileage costs. I'm currently driving a 2009 2.2 litre diesel accord and love it.. but I reckon on my commute(north dublin to citywest) i'm possibly getting about 40 mpg when traffic and everything else is considered.. bit of stop/starting on the motorway and even when I avoid the motorway there are lots of lights/junctions on the alternative roads - even if im driving more often that being stuck in traffic.

If I were driving a car that got me 60 mpg versus 40mpg - and doing 350km per week how much would I save on fuel costs roughly over 12 months? I know I should be able to work this out but my maths aint great!

Looks like your drive is mostly ubran driving. 40mpg from accord seems reasonable in such conditions.
You will find very hard to find a car doing 60mpg in urban conditions.

Anyway.
40MPG = 7.06 l/100km
60MPG = 4.7 l/100km

You travel 350km per week so you do x52 per year = 18200km.

18200km at 7.06 l/100km = 7.06*182 = 1285 litres.
18200km at 4.7 l/100km = 4.7*182 = 855 litres.

Assuming cost of litre at 1.50 we have following costs
40MPG cost - €1927
60MPG cost - €1282

You save €645.

That's assuming you will find car doing 60MPG in such conditions and it will be diesel. If it's hybrid running on petrol, savings will be less, as petrol is dearer.

Red Nissan

The theory on MPG and saving is not necessarily true. The figures for MPG are set at a fixed speed and a fixed mileage.

If you if into these parameters [you don't from your post] then a 20% saving could be expected.

However, sting in tail, at slow speeds and at idle both vehicles could be consuming the same amount of fuel.

BBC's Top Gear has done a few of these tests and to get or surpass quoted manufacturing figures on the open road is nearly impossible. So the error from what the manufacture gets on a test track could easily be in the order of your initial expected savings.

More bad news, in general the higher the MPG figure the more critical servicing is and any saving can easily be eaten up in additional service and life cycle replacements in the longer term.

Bpmull

Op to look at it simply its 40/60 mpg so what ever you spend a week/ year on fuel now you would spend 2/3 Times that on fuel if getting 60mpg. So your saving 33.33%. However getting 60mpg out of any diesel car in traffic is another story. I couldn't see any diesel doing 60mpg if the traffic was anyway heavy.

R.O.R

Simple solution is to leave earlier. If you can get past the Lucan on ramp before 07.25, you should have a clear run around the M50. If you hit Lucan after that time, then it will be chokka.

There will be a massive difference in consumption between a free flowing M50 and the stupid bumper to bumper that it can be.

Cleveland Hot Pocket

FWIW OP I do a similar drive and have found that it is not worth taking the M50. It takes less than €2.10 worth of fuel to go around the toll through chapelizod.

micks_address

I am usually on the m50 by 7.30.. i could go earlier.. but my job requires me to be in the office till after 5 so no point being in too early..

R.O.R wrote: »

Simple solution is to leave earlier. If you can get past the Lucan on ramp before 07.25, you should have a clear run around the M50. If you hit Lucan after that time, then it will be chokka.

There will be a massive difference in consumption between a free flowing M50 and the stupid bumper to bumper that it can be.

micks_address

so you reckon from a fuel perspective i'd be just as well driving 10 or 15 minutes longer and avoiding the m50 altogether?

Cleveland Hot Pocket wrote: »

FWIW OP I do a similar drive and have found that it is not worth taking the M50. It takes less than €2.10 worth of fuel to go around the toll through chapelizod.

micks_address

i'm not looking to change car at all.. just wondering how much more car is costing me in fuel as opposed to something more frugal.. (so i can sleep more content at night ) As long as its no more than 1/3rd i'd be happy enough for the comfort and enjoyment im getting out of the car..

i had hoped 40 euro of diesel might do me per week. Thats at circa 1.46 cents per litre.. it may be closer to 50... i'll see how i get on over time i guess!

But when I factor in tolls if i avoid the m50 i'll save 80 euro per week. The journey home in the evenings seems to be better though, so i might avoid the m50 in the mornings and use it in the evenings.. halving my toll bill.

Cheers,
Mick

TBi wrote: »

40MPG? I get that out of my petrol mini. I'd expect a diesel to be getting 50+.

I do about 40k km per year with a fuel bill of about €5k. Going from 40MPG to 60MPG would save me about €1,800 per year. If you could get 80MPG you'd half your fuel bill.

Try a smaller diesel (since you travel 100kph or lower) or a Prius (if you can handle the image)?

Cleveland Hot Pocket

micks_address wrote: »

so you reckon from a fuel perspective i'd be just as well driving 10 or 15 minutes longer and avoiding the m50 altogether?

For me on an average day it costs me less to drive through chapelizod than to take the toll. At worst (once I am driving through chapelizod by 7.30) it is 10 minutes extra, if that.

bazz26

TBi wrote: »

40MPG? I get that out of my petrol mini. I'd expect a diesel to be getting 50+.

I do about 40k km per year with a fuel bill of about €5k. Going from 40MPG to 60MPG would save me about €1,800 per year. If you could get 80MPG you'd half your fuel bill.

Try a smaller diesel (since you travel 100kph or lower) or a Prius (if you can handle the image)?

If the commute consists of constantly stopping and starting in traffic then irrespective of it being diesel it will not see 50+mpg on that journey. My diesel cars have always got poorer mpg in slow heavy traffic.

R.O.R

micks_address wrote: »

I am usually on the m50 by 7.30.. i could go earlier.. but my job requires me to be in the office till after 5 so no point being in too early..

I'm in a similar boat. Officially start at 09.00, but I'm in the office from before 08.00, just to avoid the traffic. Coming in from North of North Dublin, down the M1, around the M50 and off at the Red Cow. Was on the road on time this morning and there was only a slight slow down at Lucan, and I was on the Naas Road at 07.25.

Leaving in the evening's isn't usually too bad, it's the morning's where 15 minutes makes a big difference.

Cleveland Hot Pocket

R.O.R wrote: »

I'm in a similar boat. Officially start at 09.00, but I'm in the office from before 08.00, just to avoid the traffic. Coming in from North of North Dublin, down the M1, around the M50 and off at the Red Cow. Was on the road on time this morning and there was only a slight slow down at Lucan, and I was on the Naas Road at 07.25.

Leaving in the evening's isn't usually too bad, it's the morning's where 15 minutes makes a big difference.

At that time you should try (for one day) and see if bypassing the m50 toll is cheaper and still time efficient for you. You are travelling the exact opposite way that I go and traffic does seem a bit worse going "south" through chapelizod than the way I go though.

OP you won't get a cheaper car to run than a Prius on LPG.

Works out around 80 mpg equivalent.

The absolute cheapest to run is a full electric car which you can fast charge for free, even on night tariff nothing can compare.

prius needs 0 major servicing with the biggest service being engine and inverter coolant change at 100,000 miles which is not a diy job.

CiniO

Deleted User wrote: »

OP you won't get a cheaper car to run than a Prius on LPG.

Works out around 80 mpg equivalent.

Do you actually know anyone who has prius on LPG or have you ever seen one which would run without problems?

CiniO

CiniO wrote: »

Do you actually know anyone who has prius on LPG or have you ever seen one which would run without problems?

On the U.S Prius forum some lad from I think Poland converted one, there are a few around but long term results I don't know, if you were worried you can always have the flash lube system installed to protect the calves though I don't think this is necessary, but your installer should know more.

The place in Kilcullen CO. Kildare has pics of converted Prius, MK III I think.

I don't think it would be more of an issue with the Prius than with most other cars.

The only thing to ask whoever does the conversion is if it will change over straight away to lpg when it's warm because the prius turns on and off the engine a hell of a lot.

I'm sorry I didn't do it when I got it because it would have saved me a fortune. But there weren't nearly as many lpg stations as now and I don't know how long more I want to keep it but chances are I'll be keeping it a while longer.

micks_address

I would have thought travelling from swords to citywest going via clonee and lucan would be the best option for avoiding the m50?

Cleveland Hot Pocket wrote: »

At that time you should try (for one day) and see if bypassing the m50 toll is cheaper and still time efficient for you. You are travelling the exact opposite way that I go and traffic does seem a bit worse going "south" through chapelizod than the way I go though.

Cleveland Hot Pocket

micks_address wrote: »

I would have thought travelling from swords to citywest going via clonee and lucan would be the best option for avoiding the m50?

Probably would, but that isnt the way I am going, I am going from near kylemore to past blanch.