Home Home, Law & Money

Petrol Use/Engine Size

Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
Sorry if this is in the wrong forum, but I wasnt sure where to put it...

Could anyone motor-minded help me. I currently drive a Fiat Punto which has a 1.2 litre engine. My dad is getting rid of his car, and I really, really want to buy it off him, but he keeps saying its not suitable for me because

1) the insurance is in insurance group 12, whereas mine at the moment is in group 3
2) the engine is a 1.7 litre one so it'll cost me a lot more in petrol.

basically what i kind of want to know is just how much more in petrol it would cost? how do you work it out? at the moment I probably put about £20 a month in my car, I use it to make the 15/20 minute journey to work and back and to my friends etc but not long distance very often. Would a bigger engine mean I'd have to put a lot more petrol in it? would it be very expensive?

any help would be much appreciated, ta :]

Comments

  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    There's not an easy answer to that because even though it is a bigger engine it will still depend on other things like how you drive, etc.. though all things being equal yes it will use more petrol to make the same journey. If you know what car it is you could try looking up the MPG figures for your car and comparing it to the MPG figures for your dad's. It wont reflect reality but it should give you an idea of the difference.

    It is worth checking how much your insurance would change, too.
  • SkiveSkive No discipline. No morality. No respect. New ForestPosts: 15,103 I eat threads for breakfast
    There's so many variables that affect petrol consumption it's not an answer anybody can accurately give.

    Obviously a trend exists whereby the larger engines will use more fuel.
    But then some new larger engines are more economical than older smaller engines.

    Get the parker guide or research the model of car and find out the fuel consumption specific to the models and age of the cars your talking about.,
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    A comparison I once made, I have a 1.8 Focus Zetec. I get 320 miles to a 45litre fill up. My 1.3 Fiesta for 320 miles I'd fill up by 25 litres. It's a very crude comparison and you also have to factor in other things, ie size/weight of the car. My Focus is twice the size of my old fiesta, but a lot more comfortable.
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    Yes and no

    Smaller engines work harder as they have less power and a load to pull, so they are under a higher load.

    Larger engines, if you keep the revs down should be fairly economical - in theory.

    However, as UK traffic conditions are less than ideal, you're probably not looking at a decent saving!

    Just some info really - my mate had a 1.6 Escort and also a 1.1 fiesta (different times), but did the same mileage. He used to fill up with about £160 a month petrol for the Escort and about £80-90 for the fiesta. He did used to hammer the Escort though.

    What's the other car? I'm presuming some sort of Ford, possibly a puma or cougar?

    If i was you, i'd be worried more about the cost of the insurance than the cost of petrol!!!
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    thank youu, you've all been very helpful.

    yep FCUK, its a ford puma, iv sort of given up on the idea of it now because insurance as you said, is lots, car tax is more expensive and it'd use more petrol, i just cant afford all those extra things. even though i love the car, i drove it for two weeks while mine was broken and i got a bit attached to it. but guess il just have to stick with the shitty fiat for now :(

    thanks everyone though :]
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    Easiest way to get your head around it is this... - this is taking like-for-like in terms of the type of fuel - i.e, petrol vs petrol.

    If the same car had the two different engines, regardless of their capacity or maximum power output, it would need to generate the same amount of power in order to move the vehicle at the same speed, assuming the car in question was the same aerodynamic design, and the weight was the same. Even if the two engines were rotating at different speeds, power comes from a certain amount of air and fuel. You'd be using very similar amounts in both engines to move along at the same speed.

    However, in the real world, it doesn't work quite like that. Bigger engines use more when ticking over, so it's often more expensive with a bigger engine when stuck in traffic. Booting it will use more fuel in the bigger engine, as it's drawing in more air for each piston cycle and producing a lot more power in return. Bigger engines also tend to weigh more than smaller ones, so even if the car weight was equal, the bigger engine would have to haul more, affecting economy.

    I do the same trip every day, and average just over 30mpg with my 2.5 V6. This is within 0.3mpg of what I've averaged with a 1.9 and 2.0, all three engines are fuel-injected and the cars of a similar weight(though the 1.9 was in a rather light Peugeot, it did have very simple fuel injection, which isn't a patch on modern systems and will account for the relatively-poor economy). My bike, on the other hand, will easily break 40mpg despite being ridden hard(we're talking treble-figure speeds each day, with fairly rapid acceleration, though not balls-out performance) - but it weighs much, much less, and has the aerodynamics of a brick, which makes it uncomparable.

    I've also averaged 40.3mpg with the V6 on a decent-length 'A' road run, probably with a bit more to come with steady cruising on a motorway. The other 2 engines in question didn't reach quite this high on a run.

    Bottom line - if you spend a lot of time stuck in traffic, or drive with a heavy foot, chances are you'll see a sizeable increase in fuel usage. But if you're sensible, and aren't stuck in town too much, then the difference can be very minimal.
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    Are you impressed how i knew it was a puma:chin:

    I think if the insurance and higher car tax costs are putting you off, then the petrol cost doesn't even come into it!

    Save up mate and get a bigger engined car when you're older - or get your dad to keep it and add you on as a named driver:thumb:
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    FCUK it wrote: »
    Are you impressed how i knew it was a puma:chin:

    I think if the insurance and higher car tax costs are putting you off, then the petrol cost doesn't even come into it!

    Save up mate and get a bigger engined car when you're older - or get your dad to keep it and add you on as a named driver:thumb:

    i was actually! i meant to write that, how did you know, haha :]

    lol im nearly 25 now so im guessing il have to wait til im in my mid forties to be able to afford it :p im on a really rubbish wage though atm :)
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    FCUK it wrote: »
    Are you impressed how i knew it was a puma:chin:

    I think if the insurance and higher car tax costs are putting you off, then the petrol cost doesn't even come into it!

    Save up mate and get a bigger engined car when you're older - or get your dad to keep it and add you on as a named driver:thumb:

    Hahaha - I figured Puma too! ;) It's one of the few cars with a 1.7 litre petrol engine :)
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    i was actually! i meant to write that, how did you know, haha :]

    lol im nearly 25 now so im guessing il have to wait til im in my mid forties to be able to afford it :p im on a really rubbish wage though atm :)

    Check the insurance - if I recall, the 1.7 Puma was pretty pricey. I know you said group 12, but get a quote to see what the difference actually is.

    I've had everything from group 2 to group 20, and the difference has been measured in the thousands.
  • Former MemberFormer Member Posts: 1,876,324 The Mix Honorary Guru
    Yeah, when you said 1.7, i figured it was a Puma!:thumb:

    Well, i'm only 24 and i've steadily gone up in engine size from a 1.0 Fiesta, to a 1.1 metro, 1.2 clio, 1.4 206, 1.7dti Astra and recently got a BMW 120D Sport

    I was quoted £1400 fully comp with my previous insurer - no claims, and i found it for £540, so maybe you could find it cheaper!

    Try tescocompare.com
Sign In or Register to comment.