European v US automobile technology

Steve > wrote in :

> Dori A Schmetterling wrote:
>
>> It might be all the things you say, but it's not EFFICIENT, or at
>> least not as efficient, in terms of bang for the buck (KW/l)
>>
> I disagree... where can you get ANY other car with a Mustang GT's
> performance at that price? Since there's no longer a Camaro/Firebird
> and the Corvette is now up close to Viper prices, the answer is
> "nowhere."
>
> Any BMW or Mercedes that can keep up with the Mustang will cost a
> whole lot more than it does.

Bingo - right on the money. The Mustang remains true to its heritage
as the least expensive traditional pony car out there.

Whoever wrote:
>
>
> On Mon, 26 Sep 2005, Matt Whiting wrote:
>
>> Whoever wrote:
>>
>>>
>>>
>>> On Mon, 26 Sep 2005, Steve wrote:
>>>
>>> > Whoever wrote:
>>> > > > > > > > and how much torque the engine produces.
>>> > > > > > Ok, acceleration.
>>> > > > > > > > Uh, no. Torque is not the same as acceleration.
>>> > > > > > > Uh, yes.
>>> > > Torque pretty much IS the same as acceleration. Remember "F=MA"
>>> from > physics? Rearrange the equation to solve for acceleration: >
>>> Acceleration=(Force applied)/(Mass to be accelerated).
>>>
>>>
>>> Yes, but that is force AT THE WHEELS -- not at the output of the
>>> engine.
>>> Also you correctly point out that MASS is a major factor.
>>
>>
>> Yes, and force at the wheels comes from torque at the drive axle which
>> comes from torque out of the engine. Simple.
>>
>>
>>> > Torque IS the (Force applied) term when multiplied by gear ratio
>>> and > divided by tire radius and various other constants (none more
>>> > complicated than "pi"). So acceleration is DIRECTLY proportional
>>> to > torque.
>>>
>>>
>>> Torque is only proportional to accelleration if the gear ratio remains
>>> constant. My cars have transmissions that change the gear ratios. The
>>> engines in my cars don't have perfectly flat torque curves. I don't
>>> know
>>> about your cars though.
>>
>>
>> Torque is proportional to acceleration in any gear. More torque =
>> more acceleration no matter what gear you are in. You multiple torque
>> at the gears with ratios greater (numerically) than 1:1 which is why
>> the lower gears (higher numerically) provide greater acceleration.
>> They multiply the engine torque more. Acceleration is less in higher
>> gears because there is less torque multiplication. There are other
>> factors such as wind drag which increases rapidly with speed, but the
>> proportionality still holds.
>>
>>
>>> Tell me, if you are give the max torque number for a car, can you
>>> tell me
>>> the 0-60 time that car will achieve? It could be hugely different
>>> depending on the mass of the car, the power/torque curves, tranmission,
>>> etc. Torque does NOT measure accelleration.
>>
>>
>> Nobody said torque was a measure of acceleration. Everybody said that
>> acceleration was proportional to torque.
>
>
> Uh, no. I think you need to go back and read the original postings.
> Someone posted that discussing accelleration was the same as discussing
> torque -- in the context of comparing cars.

I thought the comment was that torque causes acceleration. This isn't
the same as saying that torque is a measurement of acceleration.
Gravity causes things to fall to the ground, but it isn't a measurement
of falling.


Matt

I agree that many US cars score in the kW/$ stakes and can outrun many
European cars in a straight line. Even Jeremy Clarkson agrees with that.
However, I must say I recollect driving a (what I thought large) car many
years ago in the US that had a massive 300 cubic in (c. 5 l) and at just
above 90 mph it ran out of puff, whereas our humble family Opel Rekord (GM)
and its 1700 cc engine was good for 100 mph. Of course things have moved on
but the essence remains.

Engine efficiency is kW/unit volume and many US engine just don't compete.
At the end of the day it is a matter of horses for courses and the engines
developed in different environments (demands on cars, fuel prices, taxes
etc).

Bang per buck does not necessarily refer to a literal buck :-)

DAS

For direct contact replace nospam with schmetterling
---

"Matt Whiting" > wrote in message
...
[...]
>
> Bang for the buck doesn't have units of kW/l, it has units of kW/$ or
> hp/$!!! In that regard, most American engine designs are well ahead of
> many European designs.
>
>
> Matt

Whoever wrote:


>>
>> Let me say it again: the force AT THE WHEELS is exactly proportional
>> to the force AT THE ENGINE, so for all intents and purposes
>> torque=acceleration.
>
>
> It is only proportional if you have one gear. As soon as you change gear
> the ratio changes. Also, your claim of "exactly proportional" is untrue
> even if you only consider one gear because it ignores the effects of
> power loss in the transmission.

You STILL don't get it, do you? When you shift gears, the constant
multiplier between engine torque and wheel-to-ground force changes, but
the force at the rear wheels is STILL directly proportional to engine
torque. That is ALWAYS true, regardless of gear ratio- increase engine
torque, and acceleration increases.

>
>>
>>
>>> Also you correctly point out that MASS is a major factor.
>>
>>
>> But you can't change the mass of a car a great deal. Sure, you can
>> completely change CLASS of car and get a Miata instead of a Mustang,
>> but I don't think that was the point of the point. The point was to
>> deflate some blow-hard weed-whacker driver who thinks that 200 HP from
>> 1.8 liters at 8000 RPM or with twin turbos is somehow "technologically
>> superior" to 300 HP from 4.6 liters at 5000 RPM.
>
>
> Completely missing the point. The claim of the OP was that torque =
> accelleration when comparing different cars.


No, that wasn't the point at all. The point was comparing a car (or
almost identical class of car) with an "American engineering" approach
(v8, solid axle, etc.) to a "European engineering" approach (which is
specious, because there are many big torquey European v8s, but I
accepted the original as stated for debate purposes). You can't
arbitrarily start saying "let's use a Miata sized car instead of a
Mustang for comparison."

Whoever wrote:


> Hint: if you have to say that the CONSTANT of proportionality changes,
> then it is not proportional.

Time for a review of freshman math.

"Proportionality" is preserved across a constant multiplier. Its not
preserved against non-linear operators (exponents, logarithms,
trigonometric operators, etc.). Gear ratios are constant multipliers,
therefore proportionality is preserved: if you double the engine torque,
you double the wheel torque, no matter whether or not the intervening
gear ratio is 2.76:1 or 5000:1. Its STILL proportional.

Dori A Schmetterling wrote:

> Engine efficiency is kW/unit volume and many US engine just don't compete.

I disagree with great vehemence ;-) The ONLY measure of efficiency is kW
output/(BTU/hour) input. Or in the case of a complete vehicle, its
miles/gallon or liters/km. It doesn't matter if you get 30 MPG from a
3.5L engine as an Intrepid does or from a 7L engine as the Corvette does.

> At the end of the day it is a matter of horses for courses and the engines
> developed in different environments (demands on cars, fuel prices, taxes
> etc).

Agreed on that point. But the argument that there is any "technological
merit" in high horsepower/displacement numbers has always been bogus. In
fact, it has many DISadvantages (long term reliability being the most
obvious).

On Tue, 27 Sep 2005, Steve wrote:

> Whoever wrote:
>
>
>> Hint: if you have to say that the CONSTANT of proportionality changes,
>> then it is not proportional.
>
> Time for a review of freshman math.
>
> "Proportionality" is preserved across a constant multiplier. Its not
> preserved against non-linear operators (exponents, logarithms, trigonometric
> operators, etc.). Gear ratios are constant multipliers, therefore
> proportionality is preserved: if you double the engine torque, you double the
> wheel torque, no matter whether or not the intervening gear ratio is 2.76:1
> or 5000:1. Its STILL proportional.

From Dictionary.com, definition of proportional:

3. Mathematics. Having the same or a constant ratio.

See that: "CONSTANT RATIO". It does not say "constant ratio if you ignore
factors that cause the ratio to vary".

In any case, even if you ignore the differences due to different gear
ratios, there are also many other facts such as drag, transmission losses,
etc, which mean that even in the restricted case of a single gear,
accelleration is not proportional to torque (although it will be close
for a narrow range of speeds).

>> Completely missing the point. The claim of the OP was that torque =
>> accelleration when comparing different cars.
>
>
> No, that wasn't the point at all. The point was comparing a car (or
almost
> identical class of car) with an "American engineering" approach (v8,
solid
> axle, etc.) to a "European engineering" approach (which is specious,
because
> there are many big torquey European v8s, but I accepted the original as
> stated for debate purposes). You can't arbitrarily start saying "let's
use a
> Miata sized car instead of a Mustang for comparison."

Go back to the original article. It was discussing the merits of cars
designed in US and Europe -- there was nothing that limited the discussion
to similar types of cars. In fact, the point of the article is that the
different markets has produced substantially different cars -- lightweight
cars with good dynamic handling in Europe vs. heavy cars with large
engines that have very good straight line performance in the US.

Having read the original article, then read the first comment on it by
MoPar Man:

>> and how much torque the engine produces.

> Ok, acceleration.

> Is this guy on drugs? He just said that US/Europe talks about the
> same thing (acceleration/hp/torque) while trying to make it seem that
> US/Europe talks about different things.

See that: he directly relates accelleration to torque in the context of
dicsussing different types of cars. My point has been all along that
torque is a different measurement than accelleration -- that accelleration
is a factor of many things, only one of which is torque, the other major
factors being gearing ratios, power curves, and overall mass.

On Tue, 27 Sep 2005 09:56:16 +0100, "Dori A Schmetterling"
> wrote:

>I agree that many US cars score in the kW/$ stakes and can outrun many
>European cars in a straight line. Even Jeremy Clarkson agrees with that.
>However, I must say I recollect driving a (what I thought large) car many
>years ago in the US that had a massive 300 cubic in (c. 5 l) and at just
>above 90 mph it ran out of puff, whereas our humble family Opel Rekord (GM)
>and its 1700 cc engine was good for 100 mph. Of course things have moved on
>but the essence remains.

If you have a 5.0 in a lincoln continental or grand marquis (about as
big as America builds)it will (in many cases) have a "governed" top
end of 145kph - or 90mph which is part of the emissions system.
Nothing to do with the power of the engine.
Same engine in a Mustang MAY have the same limitation. My 3.0 liter
Aerostar "hit the wall" at 140kph. Pulled pretty strong right 'till it
hit the governor.

Prior to emission controls and "big brother" getting involved, I had
several 225 inch sixes that would do over 105 MPH. ( and one 170 inch
(2.7 liter) that did well over 120) They were American. The big
difference between the 8 and the six (and the Rekord wagon) is how
quickly it got to 90. The 1700 Rekord didn't set any "records" getting
there. I've driven them.
>
>Engine efficiency is kW/unit volume and many US engine just don't compete.
>At the end of the day it is a matter of horses for courses and the engines
>developed in different environments (demands on cars, fuel prices, taxes
>etc).
>
>Bang per buck does not necessarily refer to a literal buck :-)
>
>DAS
>
>For direct contact replace nospam with schmetterling
>---
>
>"Matt Whiting" > wrote in message
...
>[...]
>>
>> Bang for the buck doesn't have units of kW/l, it has units of kW/$ or
>> hp/$!!! In that regard, most American engine designs are well ahead of
>> many European designs.
>>
>>
>> Matt
>

Whoever wrote:

>
>
> On Tue, 27 Sep 2005, Steve wrote:
>
>> Whoever wrote:
>>
>>
>>> Hint: if you have to say that the CONSTANT of proportionality changes,
>>> then it is not proportional.
>>
>>
>> Time for a review of freshman math.
>>
>> "Proportionality" is preserved across a constant multiplier. Its not
>> preserved against non-linear operators (exponents, logarithms,
>> trigonometric operators, etc.). Gear ratios are constant multipliers,
>> therefore proportionality is preserved: if you double the engine
>> torque, you double the wheel torque, no matter whether or not the
>> intervening gear ratio is 2.76:1 or 5000:1. Its STILL proportional.
>
>
> From Dictionary.com, definition of proportional:
>
> 3. Mathematics. Having the same or a constant ratio.
>
> See that: "CONSTANT RATIO". It does not say "constant ratio if you
> ignore factors that cause the ratio to vary".
>
> In any case, even if you ignore the differences due to different gear
> ratios, there are also many other facts such as drag, transmission
> losses, etc, which mean that even in the restricted case of a single
> gear, accelleration is not proportional to torque (although it will be
> close for a narrow range of speeds).


If you are going to insist on twisting the original poster's words to
make him mean "torque is the same thing as acceleration" rather than
"more torque gives better acceleration" which is what he said IN
CONTEXT, then you win by default. Congratulations. You win the pedantic
award for this month.

Now look what you did. You got everyone in an uproar discussing horsepower
and torque. It is actually quite comical, thanks!

For the casual reader, let me say that horsepower is torque x RPM. Same
thing as Watts = Volts X Amps.

For example, I can easily produce 1000 ft lbs of torque using a bicycle
attached to a gear box having a 100:1 ratio. With this I can lift a 1000 lb
load, though not very fast. Reverse this set up and I can easily spin a
shaft at 10,000 RPM, with no load attached. With this in mind, read the
discussions and have a good laugh.

Gyz

"Whoever" > wrote in message
ocaldomain...
>
>
> On Sun, 25 Sep 2005, MoPar Man wrote:
>
>>
>>> In America they talk about how many horse boxes their
>>> trucks can pull
>>
>> What's a horse box?
>>
>>> and how much torque the engine produces.
>>
>> Ok, acceleration.
>>
>
> Uh, no. Torque is not the same as acceleration.
>
>
>> Is this guy on drugs? He just said that US/Europe talks about the
>> same thing (acceleration/hp/torque) while trying to make it seem that
>> US/Europe talks about different things.
>
> acceleration is fairly closely linked to HP, but torque is different.
>
> Max torque usually occurs at much lower revs than the revs at which peak
> power occurs, so by measuring max torque you are not measuring maximum
> power. (if all engines had flat torque curves, then power and torque would
> be linked VERY closely, but they don't). It is quite possible to take two
> engines (of similar displacement) and find that one produces the highest
> torque and the other produces the highest peak power. The one that
> produces the higest torque will produce more power than the other at lower
> engine speeds and thus will probably make the vehicle in which it is
> installed easier to drive and better suited to pulling large loads.
> Engines that are optimised for the maximum power usually produce that peak
> power at higher engine speeds and thus take more effort (at least in a
> stick shift) to use that power.
>
> Secondly, acceleration is a function of many things, not just torque: the
> 2 major items being power and WEIGHT.
>