Performance VS Economy
Discussion
Vladimir said:
I was referring more to the original poster who appears to suffer from a chronic case of "PH cliche syndrome"
"Cliche" you say. As with all forum sites, the best way to get a response is to have a subject and subject header that draws people in, then the debate/banter can start, and hopefully in there you can get some useful info. Soory if you feel it is a cliche however it clearly works for you as you have taken the time to look and post. Thanks to the members who have given useful info.
Think im gonna look at the article by CH about the optimum BHP vs economy again, think he mentioned 163BHP, I am going to look at an A4 TDi S Line avant with the 170BHP engine, should tick most of the boxes.
bigsillyV10 said:
"Cliche" you say. As with all forum sites, the best way to get a response is to have a subject and subject header that draws people in, then the debate/banter can start, and hopefully in there you can get some useful info. Soory if you feel it is a cliche however it clearly works for you as you have taken the time to look and post.
Thanks to the members who have given useful info.
Think im gonna look at the article by CH about the optimum BHP vs economy again, think he mentioned 163BHP, I am going to look at an A4 TDi S Line avant with the 170BHP engine, should tick most of the boxes.
My mistake. I meant fox with his tiresome dag comment. Your post was fine and sparked an interesting thread.Thanks to the members who have given useful info.
Think im gonna look at the article by CH about the optimum BHP vs economy again, think he mentioned 163BHP, I am going to look at an A4 TDi S Line avant with the 170BHP engine, should tick most of the boxes.
Drive an A4 first though. I can pretty much guarantee it will disappoint you, despite healthy-ish performance figures. Audi is good at that.
Edited by Vladimir on Friday 16th March 10:56
Edited by Vladimir on Friday 16th March 10:57
otolith said:
300bhp/ton said:
Economy is largely going to come down to weight, although engine type/design will have a huge affect too.
Hmm, that depends in my experience. If I drive my Elise, (860kg, 189bhp) down the M4 and over the Severn crossing into Wales, and you follow me in my Saab (1740kg, 250bhp), the Saab will get marginally better fuel economy than the Lotus. Low drag and an efficient engine pulling long gears. If we then take the scenic route across country to Aberystwyth, and I drive at a speed the Saab can just about keep up with, you'll be lucky to get 20mpg while the Lotus will still do high twenties. The official figures look like this:
| Lotus | SAAB | |
|---|---|---|
| CO2(g/km) | 208 | 214 |
| Urban (cold) | 23 | 21.9 |
| Extra Urban | 41 | 42.2 |
| Combined | 32 | 31.4 |
They both do low to mid thirties on a long motorway run, the Saab slightly better. Day to day, the Saab has been averaging 26mpg with my wife commuting to work in it and the Lotus has averaged 30mpg since I bought it. It's interesting to compare what two radically different cars with fairly similar official figures get in reality.
However, let use your scenario. Take your 860kg Elise, now add 1000kg to it with no other changes. Do you still think it'll attain the same mpg (ignoring performance and handling, just mpg).
Same as with the Saab, if you could lose 800-900kg do you not think it'd be more economical?
300bhp/ton said:
However, let use your scenario. Take your 860kg Elise, now add 1000kg to it with no other changes. Do you still think it'll attain the same mpg (ignoring performance and handling, just mpg).
Same as with the Saab, if you could lose 800-900kg do you not think it'd be more economical?
Sure - but again, it depends on the circumstances. At constant speed on the flat, it would make virtually no difference, under acceleration (or uphill) it would make a huge difference. So how important weight is in determining fuel economy has a lot to do with the use the car is put to and the driving style of the driver. Same as with the Saab, if you could lose 800-900kg do you not think it'd be more economical?
otolith said:
Sure - but again, it depends on the circumstances. At constant speed on the flat, it would make virtually no difference, under acceleration (or uphill) it would make a huge difference. So how important weight is in determining fuel economy has a lot to do with the use the car is put to and the driving style of the driver.
Not many places in the UK that are flat and truly allow constant speed with no throttle modulation, not even on motorways.Point taken though, and I hope you can see mine.
BTW - to maintain the same speed with more weight would require more power, so given the same engine more throttle input, which would likely result in more fuel used.
300bhp/ton said:
BTW - to maintain the same speed with more weight would require more power, so given the same engine more throttle input, which would likely result in more fuel used.
Kind of. Ignoring the drivetrain, the two resistances to be overcome are air resistance and rolling resistance. Rolling resistance is proportional to mass and pretty much independent of speed. Air resistance is independent of mass and proportional to the square of speed. As a result, at low speeds, rolling resistance is the dominant term, but as speeds increase it rapidly becomes much less important than air resistance. So whether at constant speed a heavier car uses a noticeable amount more fuel than a lighter one depends on how fast it is going. The higher the speed, the less the difference between the two.mrmr96 said:
E46 330d.
Will do 40+mpg on a run easily. 4 adults easily. 0-60 of 7secs IIRC. Handles like a 3 series with a huge lump of pig iron in the nose
EFAWill do 40+mpg on a run easily. 4 adults easily. 0-60 of 7secs IIRC. Handles like a 3 series with a huge lump of pig iron in the nose
Mine was awful from a handling point of view. Compare it to the 323i for example. You only have to look at the heavy-duty suspension components relative to most of the other models to know theres a huge compromise there.
pilchardthecat said:
300bhp/ton said:
Not many places in the UK that are flat and truly allow constant speed with no throttle modulation, not even on motorways.
You've obviously never been to Norfolk. or Lincolnshire.
Fox- said:
A new 328i? 45mpg combined, 0-60 5.9 seconds and no crappy diesel dag.
A winner (even lacking a creamy six pot). A 320i might be a good bet too, 180bhp & plenty of torque, so not shabby. On those figures there's no need to buy an over complexed diesel at all, unless it a company motor.Fox- said:
Vladimir accusing someone else of being tiresome when it comes to diesel 
At least I'm able to form my own opinions. You just trot out the same tired old waffle. I've yet to hear even the worst diesel make a noise remotely close to "dag" so its not even an accurate snipe. Poor effort.You also claim I'm some diesel fanboy. Clearly blind to the many threads where I state most are cr4p. Only a few are good and they stand up against good petrols any day of the week. I like good ENGINES regardless of what they are fuelled by.
Anyone would think you drive some ultimate purists car. A rather tired old barge doesn't really count. Unless its an M5.
Marquis Rex said:
bigsillyV10 said:
Marquis Rex said:
Not interested in these kind of compromises forced on to us by inept government and high taxation, hence I moved to the USA for some brief relief- although this country seems to be heading the way of socialst facism heading towards the dilluded green dream also.
How much is a gallon of fuel there just now?
BMW 328 was about the best I had. Driven with an eye to economy it would probably get 40mpg and even driven enthusiastically it would average around 30, which is as good as I've ever got consistently out of any car.
Handled nicely, enough power to make A roads interesting and was pretty reliable on the whole.
Handled nicely, enough power to make A roads interesting and was pretty reliable on the whole.
GavinPearson said:
It'll be up to $6 later this year if the oil companies aren't allowed to drill for oil off the Gulf and build the pipeline from Canada.
Those two factors will have almost nothing to do with it - the real reason it'll continue to rise is because of our obsession with ramping up sanctions on Iran and the fact that majority of buyers in the oil market dont want oil they want paper futures contracts they can resell for more money a few weeks later, therefore if somebody drops a pin in Saudi Arabia they all go bonkers and bid up oil. Then the big investment banks, all with significant oil holdings, release doom-mongering self-prophecising reports every so often, too.AJS- said:
BMW 328 was about the best I had. Driven with an eye to economy it would probably get 40mpg and even driven enthusiastically it would average around 30, which is as good as I've ever got consistently out of any car.
Handled nicely, enough power to make A roads interesting and was pretty reliable on the whole.
You weren't trying very hard... mine averaged 25mpgHandled nicely, enough power to make A roads interesting and was pretty reliable on the whole.
Edited by redgriff500 on Sunday 18th March 08:36
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