> Sure, but AMD don't actually call it the XP 2.4GHz. That would be false 
> advertising - as would claiming that an engine has a displacement of X 
> when it's actually Y.

Yeh, I doubt any car makers falsely advertise the displacement.  But calling 
your car a "1.6 TDI" or whatever and it actually having a displacement of 
2000cc is probably ok (even though 90% of people would assume the 
displacement was 1.6 litres).

> Or just HP if you want to know how powerful it is,

I doubt many people are actually interested in the maximum power their 
engine can develop at one particular engine speed.  What's more useful is 
how quickly the car can accelerate, eg 40-70mph or 70-100mph times.  This 
depends on how much power the engine can develop across a wider range of 
RPMs, and also the mass of the car.

> MPG if you want to know how efficient it is... I never did understand the 
> fascination with displacement. (Other than that I guess you can 
> unambiguously measure it.)

Didn't the UK car tax depend on the displacement of your engine?  Also lots 
of racing formulas have limits on the engine displacement (eg 2400cc for F1 
currently).  The HP/litre figure is also a good guide as to how well 
engineered and advanced the engine is.  And of course higher displacement 
usually means a heavier engine, which is something you usually try to avoid.

Post a reply to this message

scott wrote:
>> Sure, but AMD don't actually call it the XP 2.4GHz. That would be 
>> false advertising - as would claiming that an engine has a 
>> displacement of X when it's actually Y.
> 
> Yeh, I doubt any car makers falsely advertise the displacement.  But 
> calling your car a "1.6 TDI" or whatever and it actually having a 
> displacement of 2000cc is probably ok (even though 90% of people would 
> assume the displacement was 1.6 litres).

Hmm, probably.

I'm pretty certain my car's engine *really is* 1.6L though. (The Haynes 
manual has different instructions depending on the size and/or year.)

>> Or just HP if you want to know how powerful it is,
> 
> I doubt many people are actually interested in the maximum power their 
> engine can develop at one particular engine speed.  What's more useful 
> is how quickly the car can accelerate, eg 40-70mph or 70-100mph times.  
> This depends on how much power the engine can develop across a wider 
> range of RPMs, and also the mass of the car.

Or that, yes.

I still find it quite impressive that a CAR, which is made of METAL and 
powered by EXPLODING PETROL, can apparently be out-accelerated by a 
cheetah, which is MADE OF MEAT. Then again, an adult cheetah probably 
weighs significantly less than an Audi TT...

>> I never did understand 
>> the fascination with displacement. (Other than that I guess you can 
>> unambiguously measure it.)
> 
> Didn't the UK car tax depend on the displacement of your engine?

Ah yes, if your car is 1.1L or less, you get cheaper car tax.

Presumably the government chose this value since all 1.1L cars known to 
man are actually 1103 cc, not 1100 cc. Hence, approximately 0.1% of the 
population qualify for this.

In any case, given that this is supposedly a "green tax", taxing based 
on emissions or fuel efficiency would seem far more logical. But then, 
the entire concept that you can make people abandon their cars just by 
making it too expensive is laughable. You make people use alternatives 
by making the alternatives ACTUALLY ****ING WORK, not just by taxing 
them off the road. But then, the former costs money, while the latter 
generates money under the pretenses of giving a **** about green, so...

> Also 
> lots of racing formulas have limits on the engine displacement (eg 
> 2400cc for F1 currently).

Yes. Presumably so that to make the car go faster, you have to actually 
*work at it* rather than just make it burn petrol faster. ;-)

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Stephen wrote:
> Eero Ahonen wrote:
> 
>>  - still having
>> 150bhp/320Nm (upgradeable to 175bhp/370Nm with just a software) with
> 
> Let’s have an argument about the difference between hp and bhp, please. :-P
> 

Bhp is a more defined unit than hp - bhp is the actual power that comes
out of the engine (and goes to the gearbox).

Well, actually bhp should be "braked" from the car itself - and they
will be, after I'll upgrade the software.

-Aero

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scott wrote:
> 
> Aren't all cars upgradeable with just software nowadays?  

Yes. Actually even my '89 9000 has upgraded software.

> In my car the
> "1.6L", "1.8L", "2.0L" and "2.3L" versions all actually have exactly the
> same engine.  

No, they are not :). The very basic engine (=the block itself) is the
same, yes.

> You are just choosing whether you want the 116, 143, 177
> or 204 BHP software installed when you buy it :-)  

Nope. The 123d has two turbochargers. The 120d has a bigger
turbocharger, different injectors, IIRC different crankshaft and some
other differencies compared to 118d. 118d and 116d may possibly be the
same engine, I haven't found theier differencies, but I'd guess that
they too have different turbos.

Yes, 1-series was one of the possibilities I though about, so I did a
little digging :p.

> I heard some people
> got up to 265 BHP out of that engine, but to me that seems really stupid
> as all the other components will not have been reliability tested at
> that power level.

I'd say that if it's done correctly, the reliability shouldn't be a
major problem on that engine (especially 123d). But the software I
referred to is a official software (by Hirch), so it won't trash the
warranty of the car.

-Aero

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Invisible wrote:
> I still find it quite impressive that a CAR, which is made of METAL and 
> powered by EXPLODING PETROL, can apparently be out-accelerated by a 
> cheetah, which is MADE OF MEAT. Then again, an adult cheetah probably 
> weighs significantly less than an Audi TT...

And probably by a lightly loaded large commercial jet, for that matter.

-- 
Darren New, San Diego CA, USA (PST)
   Forget "focus follows mouse." When do
   I get "focus follows gaze"?

Post a reply to this message

Invisible wrote:
> Space-time is an inhomogenous space anyway. I hear that gravity bends it 
> with positive curvature, but the universe itself appears to have 
> slightly negative curvature...

They're still arguing over whether it's positive or negative, or dark 
energy, or what.  There is, so far, no good way to measure the curvature of 
really big areas of space.

-- 
Darren New, San Diego CA, USA (PST)
   Forget "focus follows mouse." When do
   I get "focus follows gaze"?

Post a reply to this message

Kevin Wampler wrote:

> That said, I'm not sure it's necessary to actually understand the proper 
> definition of distance in order to talk about circles in other spaces -- 
> particularly if we limit ourselves to spherical and hyperbolic spaces 
> which are more or less easy to visualize.

Actually, I was thinking of actual real space, where the same distances are 
different depending who is measuring them. What's a circle for me isn't a 
circle for you, so I find it hard to imagine a good definition for "pi" 
under such circumstances.

-- 
Darren New, San Diego CA, USA (PST)
   Forget "focus follows mouse." When do
   I get "focus follows gaze"?

Post a reply to this message

scott wrote:
> Yeh, I doubt any car makers falsely advertise the displacement.  But
> calling your car a "1.6 TDI" or whatever and it actually having a
> displacement of 2000cc is probably ok (even though 90% of people would
> assume the displacement was 1.6 litres).

The only manufacturer I actually know done this is Saab. After all, BMW
doesn't call eg. 116d a 1.6l - they just refer to 116d (I think the
first BMW with misleading model name was 318i somewhere at 90's running
with 2.0 engine). Saab's 1.8t is actually a 2-liter engine (pretty much
the same as 2.0t) - they say that 1.8t is just the model name, not the
engine. And all the manufacturers actually have theier engine specs
available, so they aren't actually hiding the truth.

> I doubt many people are actually interested in the maximum power their
> engine can develop at one particular engine speed.  What's more useful
> is how quickly the car can accelerate, eg 40-70mph or 70-100mph times. 
> This depends on how much power the engine can develop across a wider
> range of RPMs, and also the mass of the car.

Yep, the curve telling this is called torque curve, the higher and wider
it is, more practical the car and more easy the engine usually is.
Turbocharged engines manage to get high torque even at low rpm's, so
they tend to be easy and nice to drive, even while providing high
hp/liter -ratio and reasonable economy.

>> MPG if you want to know how efficient it is... I never did understand
>> the fascination with displacement. (Other than that I guess you can
>> unambiguously measure it.)

The displacement tells you roughly how much torque you'll get from the
engine. The basic feature for a naturally aspirated engine is somewhere
around 100Nm/l nowadays - charged ones get even to 200 and over it (eg.
Saab 9-3 1.9 TTiD - 1.9 liter engine and 400Nm of torque). That also
tells you the nature of the engine - do you need to rev it to make the
car accelerate, do you need to change the gear often etc.

> 2400cc for F1 currently).  The HP/litre figure is also a good guide as
> to how well engineered and advanced the engine is.  And of course higher
> displacement usually means a heavier engine, which is something you
> usually try to avoid.

Yes, and it also tells you if the engine is nasty to drive as a
daily-driver. Sure, you can get 200hp from naturally aspirated 2-liter
engine (Honda Civic Type-R), but you'll also *need* the 4+krpm revs to
make the car actually accelerate and to find that power. Hit in a
turbocharger or even couple of them, and you'll get the power even from
1500rpm's.

-Aero

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Invisible wrote:
> 
> I'm pretty certain my car's engine *really is* 1.6L though. (The Haynes
> manual has different instructions depending on the size and/or year.)
> 

Yes, yes it is (or at least only some cm3's away from it), though 1.6l
ain't an engine - it's a coffee mug :-P.

> I still find it quite impressive that a CAR, which is made of METAL and
> powered by EXPLODING PETROL, can apparently be out-accelerated by a
> cheetah, which is MADE OF MEAT. Then again, an adult cheetah probably
> weighs significantly less than an Audi TT...

It's the grip. That cheetah has incredible amount of grip on its feet
when it goes for a prey.


-Aero

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"Invisible" <voi### [at] devnull> wrote in message 
news:4b4dd7fa$1@news.povray.org...
> I still find it quite impressive that a CAR, which is made of METAL and 
> powered by EXPLODING PETROL, can apparently be out-accelerated by a 
> cheetah, which is MADE OF MEAT. Then again, an adult cheetah probably 
> weighs significantly less than an Audi TT...

Of course, it's not what they're made of, or their mass, or what their fuel 
is, but the efficiency with which they convert their fuel to energy, and the 
efficiency with which they translate that thermal energy into mechanical 
energy. Hydraulic transfer systems can certainly be more efficient than 
complex mechanical linkages.

Of course, there are cars that can out-accelerate a cheetah. But, those cars 
have the same problem that the cheetah does... they need to stop and 
re-fuel. I expect there's a greater need for cars that keep chugging along 
without stopping, whatever speed they do it at and however long they take to 
reach that speed. :-)

--
Jack

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