HP on a grade.... KiddingHisSelf wants to know......

...... but he's too dumb to figger it out by hisself.....

Awl --

In the recent spte Volt threads/fracases, fuknKiddingHisSelf keeps
imploring/challenging me to measure the hp required to climb a grade in my
Honda ****, I mean, Fit, with a ScanGuage.

Now, Kidding needs a scanguage, cuz Kidding don't know physics or math -- or
much of anything else -- so I figgered I'd tutor him sumpn sumpn on these
fair ngs.
You no need no steenkin scanguage for this, altho you might could use one to
get a baseline hp requirement for LEVEL driving.
But even this can be calc'd with some estimate of CdA, which is actually
listed on the web somewhere, by car make. Plug in to the energy formula for
drag (cubic in velocity), and voila, you gotcher hp.

But generally, iirc, the range for maintaining 60 mph is somewhere between 5
and 20 hp, depending of course on the CdA.
I'll figger 12 hp for the Fit, which don't really matter, cuz it's the hilll
climbing addition hp we are innerested in -- and which dominates, anyway.

It's easier to do all this in metric, so convert the car weight (2500# for
the fit) to kg, 1136.
60 mph is 28.2 m/s.
Now pick yer grade:
The "legal grade limit" for highways is 6% or 3.43 deg (take the arctan of
..06 to verify this).
http://en.wikipedia.org/wiki/Interst...hway_standards

You can check the conversions at http://www.onlineconversion.com

We will calc hp at 3.43 deg (6% grade), AND at a whopping 10 deg (a 17.6%
grade)

To maintain 60 mph at 6%, the *vertical component* of the velocity 28.2 x
sin 3.43 or 1.69 m/s
Applying P = mgv, we get the power required for the *vertical component* of
this grade at 60 mph, which calcs out to 18,783 watts.
Divide by 746 (watts per hp), and the EXTRA hp needed to climb the
interstate maximum grade is a whole 25 hp -- for my Honder Fit.
Add to that the initial hp for level driving at 60 mph (12 hp), and you get
a whopping 37 hp required for a 2500# car climbing the max. allowable
interstate grade.

NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
capable of climbing max interstate grades at 60 mph.

Nest, we'll do the same for a 10 deg slope, or a 17.6% grade -- whopping
indeed -- this would be even hard to climb by foot!

The same process yields 68.6 add'l hp, for a total required 80 hp for the
Fit.... which, btw, has 108 hp..

Give or take -- and barring typos, dumb errors.

So, yeah, on VERY steep hills, the VW would slow down a bit, but BFD....
you'd be hard-pressed to find 17% grades, anyway.


If we do the same calcs for the 3800# BloatVolt, just multiply the above
grade hp by 1.5, and add the level hp.
So the Volt would require 50 hp to maintain 60 mph in max interstate grades,
and 114 hp for the very very steep 17.6% grade.

So what can we conclude from all this, boyzngerlz? Besides the fact that
Kidding is totally fulla**** (as usual).....

First, for interstate travel, the BloatVolt has THREE TIMES the required hp
for maximum interstate grade.... !!!!!
Second, for grades as high as 17%, the speed limit is probably way below 60
mph anyway, so you wouldn't even need that calc'd 114 hp, bec proly no one
else is going up that steep a grade at 60 mph either.

So if your dick is less than 3" long, go buy a 650 hp Ford GT, and feel
better about yerself.
If your dick is > 3", and you really wanna save some dough (and oil), write
fuknGM and tell them to lighten up on the fuknHP, ferchrissakes, and put out
a reasonably priced series hybrid car.
--
EA

On 5/5/2013 8:28 PM, Existential Angst wrote:

>
> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
> capable of climbing max interstate grades at 60 mph.
>
>
My '64 beetle got 29MPG on the flatland in Texas.
Half a century later, why can't cars do better?
MUCH better??

I've talked with several people driving the "smart car".
They don't even do much better than my beetle.
What gives?

Oh, my beetle didn't have any cup-holders...that must be it.

"mike" > wrote in message
...
> On 5/5/2013 8:28 PM, Existential Angst wrote:
>
>>
>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>> capable of climbing max interstate grades at 60 mph.
>>
>>
> My '64 beetle got 29MPG on the flatland in Texas.
> Half a century later, why can't cars do better?
> MUCH better??
>
> I've talked with several people driving the "smart car".
> They don't even do much better than my beetle.
> What gives?
>
> Oh, my beetle didn't have any cup-holders...that must be it.

I've been asking the same Q for years.
Ed H. called my 1971 Datsun 510 "a tuna can with a motor"..... but what a
tuna can!!!
WAAAY over 30 mpg.....

Yeah, cupholders, and airbags.... and protecting all the li'l children.....
--
EA

On Sun, 05 May 2013 20:46:15 -0700, mike > wrote:

>On 5/5/2013 8:28 PM, Existential Angst wrote:
>
>>
>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>> capable of climbing max interstate grades at 60 mph.
>>
>>
>My '64 beetle got 29MPG on the flatland in Texas.
>Half a century later, why can't cars do better?
>MUCH better??
>
>I've talked with several people driving the "smart car".
>They don't even do much better than my beetle.
>What gives?
>
>Oh, my beetle didn't have any cup-holders...that must be it.

Nope. My 2003 Impala has cup-holders and gets better MPG than my '64
bug did, Weighs more than twice as much as the bug too. The bug was
a shade over 1600 lbs,
And the bug was just barely better than a loaded semi-truck doing
mountain grades. Crossed the Rockies a couple times with mine.
Real fun getting pushed over a few feet by the wind around a semi.
Anyway, I knew my bug up and down, and while it had its place, there's
very little to compare with a modern car.
You can get about 50% better mpg in a Chevy Eco Cruze (gas engine
only) and it weighs +3000 lbs. There's others.
I was fond of my bug, and it was the first engine I rebuilt, but it
was basically a lawn mower compared to modern cars.
Don't need to be scraping ice off the inside of the windshield as I
drive anymore either.

On 5/5/2013 10:28 PM, Existential Angst wrote:
> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
> capable of climbing max interstate grades at 60 mph.[...]

I can assure you that a 1979 VW Rabbit with ~600 pounds of people and
luggage was *not* capable of maintaining the then 55-mph speed limit on
I-70 uphill between Denver and Vail. Much of the time was spent at
~40-mph in 3rd gear at full throttle.

Calculating power needed uphill without including at least the weight of
the driver is not very useful.

--
T0m $herm@n

"T0m $herman" > wrote in message
...
> On 5/5/2013 10:28 PM, Existential Angst wrote:
>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>> capable of climbing max interstate grades at 60 mph.[...]
>
> I can assure you that a 1979 VW Rabbit with ~600 pounds of people and
> luggage was *not* capable of maintaining the then 55-mph speed limit on
> I-70 uphill between Denver and Vail. Much of the time was spent at
> ~40-mph in 3rd gear at full throttle.
>
> Calculating power needed uphill without including at least the weight of
> the driver is not very useful.

Well, you can redo the math to account for those people, AND different
angles.
Multiply the uphill hp amt by 1.3 or so, for 600# of people.
Also, that 6% grade is a modern spec., I'm sure there are steeper grades
grandfathered in here and there.

If grades are really an issue, then mebbe more hp is req'd in your case.
And certainly in Kidding's case.

The point was to show that in "green times", hard times, oil-scarce times,
we can do with much less hp than we're being fed.
Proly 42 hp was pushing it, but...... 40 mph fully loaded up a steep hill
ain't so bad....
Oh, in your case, it would proly be 54 hp.... Still, there are grades and
there are grades....

I'd be curious to know just what those grades were, ito %, see how your
experience jives with the math.
--
EA


>
> --
> T0m $herm@n

On 5/6/2013 5:50 AM, Existential Angst wrote:
> "T0m $herman" > wrote in message
> ...
>> On 5/5/2013 10:28 PM, Existential Angst wrote:
>>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>>> capable of climbing max interstate grades at 60 mph.[...]
>>
>> I can assure you that a 1979 VW Rabbit with ~600 pounds of people and
>> luggage was *not* capable of maintaining the then 55-mph speed limit on
>> I-70 uphill between Denver and Vail. Much of the time was spent at
>> ~40-mph in 3rd gear at full throttle.
>>
>> Calculating power needed uphill without including at least the weight of
>> the driver is not very useful.
>
> Well, you can redo the math to account for those people, AND different
> angles.
> Multiply the uphill hp amt by 1.3 or so, for 600# of people.
> Also, that 6% grade is a modern spec., I'm sure there are steeper grades
> grandfathered in here and there.
>
> If grades are really an issue, then mebbe more hp is req'd in your case.
> And certainly in Kidding's case.
>
> The point was to show that in "green times", hard times, oil-scarce times,
> we can do with much less hp than we're being fed.

True. My 2002 Nissan Frontier is rated at 170-HP, but can still get up
to 50+ mph at the end of most on-ramps pulling a 2-ton trailer. So the
350-500 HP we see these days in full-size pick-ups is ridiculous
over-kill. And the average new minivan with a V-6 these days has a
better power-to-weight ratio than mid-1970's to early 1980's Corvette or
Ferrari 308.

> Proly 42 hp was pushing it, but...... 40 mph fully loaded up a steep hill
> ain't so bad....
> Oh, in your case, it would proly be 54 hp.... Still, there are grades and
> there are grades....
>
It was as 6-year old Westmoreland (US built) Rabbit, so broken in, but
not yet enough mileage to cause significant compression/power loss.

One thing to remember is that SAE, DIN, JIS, et al horsepower is
measured at the crank. I have a much better feel for motorcycles due to
rear-wheel horsepower regularly being measured and published, but this
is rare for cars (some of the 4WD truck magazine occasionally publish
dynamometer tests). But as a rule of thumb, power losses may range from
about 10% for a motorcycle with a properly tensioned and lubricated
chain, to more than 30% for a 4WD pick-up (so my Frontier mentioned
above likely has 120-130 HP at the rear wheels).

> I'd be curious to know just what those grades were, ito %, see how your
> experience jives with the math.
>
You can estimate from a USGS topo quad, and sometimes from county GIS
servers. There is also aerial laser topographic coverage in many areas,
but requires special software to use. In the case of Rocky Mountain
passes, Interstate highway may exceed 6% grades due to the huge costs of
tunnels required to achieve lower grades.

--
T0m $herm@n

On Sun, 05 May 2013 20:46:15 -0700, mike > wrote:

>On 5/5/2013 8:28 PM, Existential Angst wrote:
>
>>
>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>> capable of climbing max interstate grades at 60 mph.
>>
>>
>My '64 beetle got 29MPG on the flatland in Texas.
>Half a century later, why can't cars do better?
>MUCH better??

My '64 Beetle got 30 mpg highway, too.

Because our Beetles were frail little deathtraps that wanted to kill
us, and couldn't get out of their own way going up a 2% grade.
Zero-to-sixty time was...one lunchtime. <g>

I alwasy figured they were the Nazis' revenge for WWII.

>
>I've talked with several people driving the "smart car".
>They don't even do much better than my beetle.
>What gives?

The US versions have stunk in the efficiency department. I don't know
why. The European versions supposedly do much better.

>
>Oh, my beetle didn't have any cup-holders...that must be it.

Heaters. I lived in Michigan at the time. Unless you had one or two of
those JC Whitney add-on heater blowers, your windshield could freeze
up -- on the inside. d8-)

--
Ed Huntress

On Mon, 6 May 2013 00:09:50 -0400, "Existential Angst"
> wrote:

>"mike" > wrote in message
...
>> On 5/5/2013 8:28 PM, Existential Angst wrote:
>>
>>>
>>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>>> capable of climbing max interstate grades at 60 mph.
>>>
>>>
>> My '64 beetle got 29MPG on the flatland in Texas.
>> Half a century later, why can't cars do better?
>> MUCH better??
>>
>> I've talked with several people driving the "smart car".
>> They don't even do much better than my beetle.
>> What gives?
>>
>> Oh, my beetle didn't have any cup-holders...that must be it.
>
>I've been asking the same Q for years.
>Ed H. called my 1971 Datsun 510 "a tuna can with a motor"..... but what a
>tuna can!!!
>WAAAY over 30 mpg.....

I thought your tuna can was a 210? That's the one I called a tuna can.

The 510 was a mechanical copy of a BMW 1500. It was an excellent car
-- Japan's first high-volume production car made with a unibody. It
was the car to beat in several SCCA classes over the years, right up
through the mid-'80s when it was the fastest car in ITC (the Old
Junque class).

The 210 was, IIRC, a body-on-ladder-frame structure. One excellent and
iconic Brit book on chassis said that type was obsolete in 1962. Only
210s were made a decade later. d8-)

>
>Yeah, cupholders, and airbags.... and protecting all the li'l children.....

I liked the handstraps on the old VWs. I miss them. And the shims on
the fan belt drive pulley that were supposed to let you easily adjust
the tension, but which tended to rust into a unified lump.

And, of course, the front-end torsion bar adjustment. That was good,
because the damn things sagged after 50,000 miles or so. Of course,
most drivers never noticed, because the antique
trailing-arm/swing-axle suspension combination was so foul, and so
dangerous, that any deterioration in handling slipped below conscious
awareness, as you were lucky just to keep the rear wheels from jacking
and sending you into a spin.

It was a fine piece of engineering -- for 1936, when it was designed,
and when it had a top speed of something like 45 mph.

--
Ed Huntress

On 5/5/2013 11:46 PM, mike wrote:
> On 5/5/2013 8:28 PM, Existential Angst wrote:
>
>>
>> NOW -- the 1960/70 Beetle had 42 hp (before it jumped to 54), at only
>> 2,000#, so, contrary to the smugly ignerintKidding, the VW was MORE than
>> capable of climbing max interstate grades at 60 mph.
>>
>>
> My '64 beetle got 29MPG on the flatland in Texas.
> Half a century later, why can't cars do better?
> MUCH better??
>
> I've talked with several people driving the "smart car".
> They don't even do much better than my beetle.
> What gives?
>
> Oh, my beetle didn't have any cup-holders...that must be it.

It also had an ashtray! How un-pc today.