1998 Grand Caravan

I suspect at least some of that 33% is not true loss, but, as I said in
another post, some have speculated that a seemingly excessive loss
figure is due to DC's possible exaggerated engine output claims being
eplugged into the efficiency formula as the input.

Well you just shot your argument in the foot because LH cars do in fact
have *two* coolers: The radiator tank (of course acting more as a temp.
stabilizer or buffer), plus an air coil hung out in front of the radiator.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

You've just proven your ignorance of the English language. Wow - I was
only halfway kidding that you would be equating 'accepted' and
'acceptable' - I didn't think anyone could be that ignorant, but I guess
I was wrong (see - I can admit mistakes on my part). But I guess to
you, someone stating facts is "talking down" to you. I'm starting to
understand your inferiority complex.

I could explain the difference between 'accepted' and 'acceptable' but
something tells me that you still wouldn't get it and/or would want to
continue arguing against the obvious. I bet my teenage daughter
understands the difference. I try to avoid such imbecilic discussion -
though with you it is difficult. I have said before that sometimes it
is difficult to separate out dishonesty and stupidity, and you're
illustrating why (you have to make up explanations to justify an
erroneous position that you don't even understand but don't even realize).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Budd - I'll say this in the least offensive way I know how (Matt said it
and I said it before): Torque and energy are different units - losing
torque thru levering or gearing is not in itself energy loss. Energy is
work x speed x time. In your lever and gear examples, what you lose in
torque you gain in speed - the product of the two is proportional to
energy and will be the same - except - yes - for some energy loss due to
friction, but that friction is not inherent in the lever or gear
multiplication or division factor. Think about this example: Situation
1 - The fulcrum point is on a sliding friction bushing. Situation 2 -
The fulcrum point is on a roller bearing of some sort. If you truly
think it thru, you will realize that there are friction losses in both
cases, but it is not directly related to the ratios. You will also have
sliding friction between the gear teeth - but its amount is not a given
relation to the torque multiplication factor - it can be varied all over
the place depending on wheter it is lubed or not, and if lubed, what
lube is used.

I will give you that, simplisitically speaking, if you have two meshed
gears for one multiplication factor, you will have half the friction
losses than if you have a series of two pairs of meshed gears to achieve
the same final ratio (the difference between the OD and direct drive
scenarios). But *that's* where the added losses are coming from that
you're talking about - not in the ratios themselves.

In a nutshell, as I and Matt have already pointed out, your fallacy in
your explanation is in trying to equate torque multiplication with
energy multiplication. You trade off torque and speed, and energy being
the product of the two (with time factored in), well - you do the math.
The same kind of arguments occur about torque and horsepower because
of the same failure on people's part to understand what they are
mathematically (and in reality).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Less torque, yes, but not less power. Efficiency is related to
energy/work/power, not force/torque.

I see the problem now. You are talking about engine efficiency, not
gear ratio "efficiency" whatever that is. Keeping the engine in an
efficient RPM range is a different discussion altogether, but, again, it
doesn't matter how you keep it there (whether OD tranny and numerically
higher rear end ratio or 1:1 transmission and a lower numerically rear
end ratio. I thought that was your original argument, but you've now
changed horses mid-stream. I'm still waiting to see how moving the
point of reduction from the rear axle to the transmission makes a
fundamental change in efficiency of power transmission.


Matt

 

No, I'm not. Look up any definition of efficiency. I will not involve
forces or torques (just force in a rotational form). It will involve
energy (or work or power). Gear ratios don't have efficiencies, that is
the point.

You are confused. You need to refresh your memory on some basic physics
definitions.

And, again, I say you need to look up the definition of work and apply
it to both sides of your transmission. Assume for the moment that there
are no frictional losses since the discussion here is the gear ratio
itself. Now try different gear ratios and compute the work at the
output vs. the input and divide to get the efficiency. Show us how
different ratios change the efficiency. The only requirement is that
you must use the correct definition of efficiency, which you haven't
thus far. Look it up, it is in any high school physics book or easily
available via Google.

Matt

 

Budd Cochran wrote:

They are if they have an engineering degree from an ABET accredited
university. If they don't, then they aren't unless they hold the PE
license.

Matt

 

But that has nothing to do with the gear RATIO. It has to do with how
you achieve the overall reduction ratio, but it isn't related to the
ratio itself, that is the point. Sure, if you use 10 sets of gears to
achieve a 2:1 reduction that will have more parastic loss than using one
gear set. However, it doesn't matter what the reduction ratio is. It
could be 10:1 or 100:1. What matters for frictional loss is how many
mechanisms you traverse, not what the ratio is.


Matt

 

Bill Putney wrote:

Wouldn't be the first time.

Is the cooling capacity of these two equal to the engine radiator? If
it is, then maybe the 33% loss is closer to reality, but I still HIGHLY
doubt it. Is the fuel economy of this car much worse than similar
weight and horsepower cars?


Matt

 

Yes, it does. OD ratios are inefficient, like it or not.

The lower the efficiency of the ratio plus the extra parasitic losses from
extra gearsets equals a stupid design. (KISS principle).


--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

Hold it!!! Hold the presses!! You just contradicted yourself. First you say
there is no energy loss then there is . . you don't know squat.

What the fixation with friction losses?? Is it some thrill for you? How many
times must I agree that there is parasitic losses before you set them aside
and discuss ratios?

Reading comprhension isn't your strong point is it? Again, how many times
will I hacve to tell you that I agree with this BEFORE IT GETS THRU YOUR
THICK SKULL ( no, I am not a politically correct person, thank you)

I did the math and the net effect is a major measurable loss of efficiency.

No, the same arguments happen because overeducated idiots like yourself have
the misconception you know everything.

The only reason you think I'm in error is because you added parasitic losses
into a discussion ABOUT RATIOS.

So, you failed to discuss the topic.
--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

Then how come cars running north of me at the Bonneville salt flats run
faster with low numerical axles and direct trans ratios than cars with
higher numericals and OD ( case in point: Summers Brother's Goldenrod. A
still standing land speed record with a car that could not pull in 4th gear,
that is OD).

No, I'm talking ratio efficiency, but you keep avoiding / clouding the
topic.

You'll never find it. Your head is buried in the sands of overeducation.


--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

ROTFLMBO!!!! Spoken like a well trained engineer.

Matt, I've worked on gear trains that make automotive, even semi truck
transmissions, look like toys and gear ratios do have efficiency quotients.

No, that would be you.

Make up your mind . . .parasitic losses or no parasitic losses . . .never
mind. The fact you keep changing the "rules" means you've lost the
discussion.

Why? You're not using the laws of physics, why should I?


--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

Aha, so you do want to be selective, but will not allow me the same
privilege.

--
Budd Cochran

John 3:16-17, Ephesians 2:8-9

"Our Constitution was made only for a moral and religious people.
It is wholly inadequate for the government of any other."
(John Adams)

 

Can I get some of that "overeducation"?

Roy

 

AH, Bill, you-da-man! Good job. I hate lawyers after the crap that
happend in my divorce.

Nice to hear that you managed (no pun intended) to avoid some nasty
legal crap.

But do tell, message from God? A dream perhaps?

(e-mail privately if you wish).

 

I'm starting to

The only "inferiority complex" around here is those who feel they need to
wave diplomas and position at others in order to "win" an otherwise factual
discussion.

I could explain thats its merely a matter of tense...

Main Entry: ac·cept·able
Pronunciation: ik-'sep-t&-b&l, ak- also ek-
Function: adjective
1 : capable or worthy of being accepted <no compromise would be acceptable>

Main Entry: ac·cept·ed
Function: adjective
: generally approved or used
- ac·cept·ed·ly adverb

But I'd bet you would argue with Merriam Webster about it, so I'll just let
it be at that.

Yeah, I bet she does... she likely does things to be ACCEPTED that you don't
find ACCEPTABLE.

Except that you engage in it almost every time you post.....

Not really, drop the pretentious attitude and you'll find that most people
will like you better.

Ya see, I knew ya couldn't do it. I asked you to be succinct, and you
failed. You instead resorted to personal attack as a means of reply. And
that after I tried to explain to you why you get perceived a certain way.

So go ahead, continue your acrimonious behavior, and stop asking why people
think of engineers as pretentious and egotistical.


--
Max

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

 

They are if they have an engineering degree from an ABET accredited

Another fine example of how engineers have little time for those without
better credentials than their own.

Those mentioned by Budd are in fact engineers, just not the same type as
your exalted number crunching know-it-alls. Most of those named by Budd
probably know more about their respective equipment than the engineers that
created the equipment on paper.

--
Max

"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)

 

It doesn't matter if I life it or if you like it. It is simply a dumb
statement. A gear ratio is neither inherently efficient or inefficent.
A given engine runs efficiently within a certain RPM range. A given
gear ratio may or may not keep the engine in that range, but it doesn't
matter if the ratio is an OD ratio or not. Some diesel engines are most
efficient between 1500 and 2000 RPM and often an OD ratio is just the
ticket to keep them in that range.

There is no efficiency to a ratio so it can't be lower (or higher) as it
simply doesn't exist. For one who keeps referencing math and physics,
you have a very meager comprehension of either.

Matt

 

Because the OVERALL gear ratio wasn't correct for the power curve of the
engine. Ideally, you want the overall ratio to be such that the engine
hits its peak horsepower RPM at exactly the same time that the car hits
its maximum aerodynamic drag speed. If the car is geared too tall,
which this one obviously is, then the aero drag on the car is increasing
faster than the power curve of the engine and once they cross, the car
will no longer gain speed.

This could easily be fixed by using a numerically higher rear axle
ratio. It has nothing to do with the transmission having a ratio less
than 1:1, it has everything to do with the OVERALL reduction ratio of
the driveline being incorrectly matched to the engine for this
particular situation (top speed on the level).

That is because the topic simply doesn't exist. Find us even one
reference that talks about a gear ratio efficiency. Just one...

I won't find it because it doesn't exist. And that is the same reason
that you can't find it and post a reference to it.

Matt