Does a higher litre figure mean a car is less economical?

[Z064life]

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

[billberks2]

no usually the lower litre the higher fuel consumption

ie 4.4 rangie is much more economical than smart car

[herewego]

I'd pop down to the library and get yourself a basic book about cars.

[clonmult]

billberks2 said:

no usually the lower litre the higher fuel consumption

ie 4.4 rangie is much more economical than smart car

Ergo a Veyron is one of the most economical cars on the planet.

[Mr POD]

A mate with a 2.0 XE Astra GTE 16V reckons that on a run he can see 40 MPG

THE most I've ever had from a 1.6 8V Astra mk3 was 35 mpg.


Combinations of higher gearing, more efficient breathing, higher torque at lower revs.

[petermansell]

Z064life said:

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

It depends who you are. People who know little about cars and see themselves as environmental champions may hate large engined (and "flashy") cars and those who drive them not so much because they know whether, how and to what degree they pollute. Rather it’s what they represent (hedonism as distinct from social responsibility). Of course much of the time they talk b cks. That’s why I drive a 5.5ltr AMG

[Z064life]

herewego said:

I'd pop down to the library and get yourself a basic book about cars.

I agree.

[renrut]

As a general rule yes, however the difference is often wildly exaggerated and of course depends as much on how its used.

I suggest you go look up how a 4 stroke engine works and then you'll understand the number of variables that can be played with and optimised.

Here's as good a starting place as any:
http://en.wikipedia.org/wiki/4_stroke

[Skodaku]

Z064life said:

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

How can you have been on PH since 2003 and are now asking this question ? Is your degree course in Basket Weaving by any chance or perhaps Media Studies ? Sorry, not trying to be offensive but the questions astounds me.

[Z064life]

Skodaku said:

Z064life said:

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

How can you have been on PH since 2003 and are now asking this question ? Is your degree course in Basket Weaving by any chance or perhaps Media Studies ? Sorry, not trying to be offensive but the questions astounds me.

Er, maybe because since 2003 my posting activities on here may have been stretched and not frequent?

My degree should be in dealing with idiots like you. Unfortunately, it is in Business and Management (Computing).

I have been interested in how cars work since I was very young, being exposed to garages and mechanics were I picked up the terms and basic knowledge, but my learning on how cars work has followed a scattergun approach. After all, my career orientated skills come first.

[RedYellowGreen]

It depends what type of engines ie n/a or super/turbo charged.
It also depends on driving style too, witness the recent top gear test with the bmw m3 and toyota pious, alright it wasnt very scientific and typical tg peetake but it did show that a bigger torquey engine can compare well to a thrashed small one in fact it reminded me of 2 of my old cars.
1. MX5 1.6 detuner(mk1) and 2. MX5 1.8is(mk2). In general driving the mpg was very similar despite no2 carrying more wheight, 200cc more engine capacity and 50bhp more power. Even when er pushing on mpg was similar the only advantage to no1 was in eco mode ie cruising at 60mph max in 5th gear (which was rare ) when I could ring a tank of petrol out for a huge distance, a similar driving style in no2 made little difference to mpg. I put this down to the fact that no2 could keep up with the traffic flow on much smaller throttle openings than no1 due to possesing more torque also perhaps development to the motors over time by Mazda themselves.

[Dracoro]

Skodaku said:

Z064life said:

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

How can you have been on PH since 2003 and are now asking this question ? Is your degree course in Basket Weaving by any chance or perhaps Media Studies ? Sorry, not trying to be offensive but the questions astounds me.

I think you need to have a little think about what you just posted.

Many people are in to cars but not necessarily care about under the bonnet (nor do they read every single post in PH to find out). Then one day said person decides, "hey, lets find out a little bit more about what's going on under the bonnet" and gets people like you being silly and sarcastic.

It's a genuine question, let people answer it.

[crofty1984]

In VERY coarse terms:
The more power a car makes the more fuel it uses. Of course, like for like, it is possible that out of two engines that are identical in every respect except displacement, the larger one will have more power so your inital theory rings true.

In reality it's more complicated than that, and there's a lot to be taken into consideration.

Get a bottle full of petrol, now if burned in the right conditions it will release a certain amount of energy, not less not more (If you can figure out how to make it release more, congratulations, you've just invented perpetual motion!)

OK. So to get 100hp of power (energy released in a set amount of time) you have to burn 100HP's worth of fuel.
So you can see that If you had a small powerful engine, like a suzuki hayabusa motorbike at 180HP over 1300cc and a 1.8l car making 100hp, The suzuki engine would be less economical.

Of course, that's if they're in the same vehicle, told you it was complicated!

Also you have to think how hard the engine has to work, pehaps the car's heavy, or less aerodynamic, perhaps there's crap rolling round in the boot, maybe the driver rags it about. A heavy car might need 70hp to push it along at 50MPH, whereas a smaller lighter car with top-quality oil in, and properly inflated tyres might only need 40hp to push it along at 50MPH, therefore using less fuel.

And on top of all that, ALL engines are inefficient! the point above about burning 100hp's worth of fuel to get 100h out is balls, really as far as the chemistry's concerned you may need to burn 200hp's worth as half will be wasted, but perhaps there's a really efficient buning engine, where you only have to put 175hp's worth in.




...And breathe!

[Robinlarge]

It all boils down to the efficiency of the engine and engine management system, the weight of the vehicle (and occupants) and the style of driving.

I drive an 8.3l twin turbo SRT 10 - it does 12.5mpg - because it is heavy - but that is the same through towns or on a decent run - because it is very efficient.
However it is not aerodynamic so as soon as I step over around 95 that goes down rapidly to closer to 10 to the good old gallon.

I can calculate what it will do at 185mph but dont think I can afford it!

[BrassMan]

crofty1984 said:

In reality it's more complicated than that, and there's a lot to be taken into consideration.

OK. So to get 100hp of power (energy released in a set amount of time) you have to burn 100HP's worth of fuel.
So you can see that If you had a small powerful engine, like a suzuki hayabusa motorbike at 180HP over 1300cc and a 1.8l car making 100hp, The suzuki engine would be less economical.

Then you get onto efficiency, which is limited by the compression ratio of the engine, that is the ratio of volumes of the cylinder at the beginning and end of the cycle. If I remember correctly, a petrol engine is unlikley to get better than 40% before it suffers detonation, while a diesel will be a few (can't be bothered to look up how many) points higher, which is one of the reasons why diesels get slightly higher MPGs.

Now imagine a turbocharged engine with a lowered compression ratio and an inlet pressure of two bar absolute, what would you expect to happen to the efficiency? See the top of this post.

[Skodaku]

Dracoro said:

Skodaku said:

Z064life said:

When a car is said to be 3 litre, 1 litre, or 8 litres, it means the amount of air the cylinders can hold, right?

So is it a stigma when a car with a bigger litre count is said to be more polluting?

A new golf can get 50mpg, but a new Accord with a diesel 2.2 litre engine (note, bigger litre count) can get 60mpg. Both cars not being hybrid.


http://uk.cars.yahoo.com/car-reviews/car-and-drivi...
http://www.autospies.com/news/2008-Honda-Accord-to...

How can you have been on PH since 2003 and are now asking this question ? Is your degree course in Basket Weaving by any chance or perhaps Media Studies ? Sorry, not trying to be offensive but the questions astounds me.

I think you need to have a little think about what you just posted.

Many people are in to cars but not necessarily care about under the bonnet (nor do they read every single post in PH to find out). Then one day said person decides, "hey, lets find out a little bit more about what's going on under the bonnet" and gets people like you being silly and sarcastic.

It's a genuine question, let people answer it.

Yep, You're correct. Inappropriate post for which I apologise. Looks like the OP's degree course will also equip him rather well to deal with idiots.............he's going to meet lots of those over the years.

[K20CRX]

Absolutely hilarious!