mazdaspeed 6 vs TL

[jediali]

Ironically that can be the opposite too. Cars with higher specific output require higher octane gas(the Mustang GT gets 300hp on 87 octane because it doesn't have a high compression ratio, while almost all other performance cars run 91+octane), usually engine parts are more expensive, and your gas mileage will be generally lower than a car with a lower specific output.

higher octane is needed for higher compression ratios but not high operating rpm. Most of the advances in power/litre i have read about have arised due to combustion efficiency, variable geometry/valving, and clever auxilary power consumption reduction, all of which are inexpensive and don't require higher octane fuel.

you aint wrong and i amnt disagreeing, just my 2 cents

[Ferrer]

Alright, with the certain countries who have pointless laws like that sure.
And displacement does not indicate gas mileage. My 3400lbs car with a 5.7L V8 gets better gas mileage than some 4 cylinders(especially turbocharged ones)... What does show gas mileage is weight, aerodynamics, and gearing.

Ironically that can be the opposite too. Cars with higher specific output require higher octane gas(the Mustang GT gets 300hp on 87 octane because it doesn't have a high compression ratio, while almost all other performance cars run 91+octane), usually engine parts are more expensive, and your gas mileage will be generally lower than a car with a lower specific output.

They might be stupid but it's what we have. And while you are right that engine displacement does not determine fuel consumption, usually having a big engine doesnt help. As an example the Chrysler 300C 5.7 V8 does 12,1l/100km (19,4mpg US) and the BMW 550i (4.8-litre) 10,3l/100km (22,8mpg US).

[Kitdy]

They might be stupid but it's what we have. And while you are right that engine displacement does not determine fuel consumption, usually having a big engine doesnt help. As an example the Chrysler 300C 5.7 V8 does 12,1l/100km (19,4mpg US) and the BMW 550i (4.8-litre) 10,3l/100km (22,8mpg US).

Ferrer, while I tend to agree that in general a larger engine would use more engine than a similar engine, your example is very poor as it illustrates only one select situation out of many. I would say it would have been better just to state the fact in general as opposed to using an example at all.

[Ferrer]

Ferrer, while I tend to agree that in general a larger engine would use more engine than a similar engine, your example is very poor as it illustrates only one select situation out of many. I would say it would have been better just to state the fact in general as opposed to using an example at all.

I could go thorugh other examples, but even I don't have unlimited time...

[Ingolstadt]

Ferrer, while I tend to agree that in general a larger engine would use more engine than a similar engine, your example is very poor as it illustrates only one select situation out of many. I would say it would have been better just to state the fact in general as opposed to using an example at all.

I believe if you insist, he could embarressed you as well.

[Slicks]

They might be stupid but it's what we have. And while you are right that engine displacement does not determine fuel consumption, usually having a big engine doesnt help. As an example the Chrysler 300C 5.7 V8 does 12,1l/100km (19,4mpg US) and the BMW 550i (4.8-litre) 10,3l/100km (22,8mpg US).

What an unbiased comparison considering the BMW has an extra gear...

[Ferrer]

What an unbiased comparison considering the BMW has an extra gear...

Ooooh poor Chrysler, all their cars should be relieved from competing with rivals because they can only do 5-speed gearboxes...

[jediali]

What an unbiased comparison considering the BMW has an extra gear...

technically a 5 speed can be geared better for economy than a 6 speed. plus it could be lighter too.

[Slicks]

Ooooh poor Chrysler, all their cars should be relieved from competing with rivals because they can only do 5-speed gearboxes...

Well if you want to try and show that larger displacement engines get worse fuel economy, then do it by making all else equal. Your example only proves that gearing is a major factor in gas milage, not displacement...

[Slicks]

technically a 5 speed can be geared better for economy than a 6 speed. plus it could be lighter too.

The weight loss would be so litte that it would be insignificant. And a 6 speed can be geared much better for fuel economy.

[Ferrer]

Well if you want to try and show that larger displacement engines get worse fuel economy, then do it by making all else equal. Your example only proves that gearing is a major factor in gas milage, not displacement...

It's funny you should mention that because actually Chrysler's 5th gear is longer than BMW's sixth, which theoretically should help the Chrysler. And actually the Mercedes-Benz E 500 (5.5-litre engine) has a worse fuel consumption than the BMW (11,5l/100km) despite having a 7-speed gearbox, and both 6th and 7th longer than the BMW, which leads me to believe that actually engine displacement might affect in some way fuel consumption.

[jediali]

Well if you want to try and show that larger displacement engines get worse fuel economy, then do it by making all else equal. Your example only proves that gearing is a major factor in gas milage, not displacement...

is this any use?:

[Kitdy]

is this any use?:

That, for example jediali, is a very good example. It is not concrete proof by any means, but it is an excellent snapshot.

[Ingolstadt]

What an unbiased comparison considering the BMW has an extra gear...

You need not protect them to this extent. seriously, it sucks reading such comments from knowledgable guys like you.

[Slicks]

It's funny you should mention that because actually Chrysler's 5th gear is longer than BMW's sixth, which theoretically should help the Chrysler.

Yeah, by .04:1, very insignificant. Also I just noticed the 300C is 300lbs heavier than the BMW...

And actually the Mercedes-Benz E 500 (5.5-litre engine) has a worse fuel consumption than the BMW (11,5l/100km) despite having a 7-speed gearbox, and both 6th and 7th longer than the BMW, which leads me to believe that actually engine displacement might affect in some way fuel consumption.

Funny, I found different:
MB E550 (the only 5.5L V8 MB E-class I found): 15/23mpg
BMW 550i: 14/21