[DeTomaso] Rear Window
Stephen
steve at snclocks.com
Fri Mar 18 12:27:44 EDT 2016
Cameras are not the problem, it is lighting. Ambient is flat bright – I had an led light shining on the gauges but not bright enough to compensate for the sky in the background. Hopefully the next session will be on a cloudy day, or I can run it at night.
With an engine that dyno’d at 480 hp, I am just not all that concerned with power. I don’t run the car all that hard, and suspect that inlet air density will never be an issue.
I was surprised to see positive pressure in the compartment – won’t compensate for much temperature increase (vis-à-vis air density) but does raise questions on the impact of a belly pan below the engine – increased rear lift? Now I am totally outside of my knowledge band.
Stephen Nelson
SNClocks.com <http://www.snclocks.com/>
Click here to join one of our mailing lists Contact Lists <http://fs19.formsite.com/kagforms/form675003155/index.html>
Click here for our new <http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/About-Steves-Dulcimers/19824807_4sHGgj#1558377542_LKmkrT7> Hammered Dulcimers galleries
Click here for my new blog <http://www.perfectoldman.com/> on finding happiness in retirement
From: Michael Shortt [mailto:michaelsavga at gmail.com]
Sent: Friday, March 18, 2016 8:57 AM
To: Stephen <steve at snclocks.com>
Cc: detomaso at poca.com
Subject: Re: [DeTomaso] Rear Window
Stephen,
I would simply borrow, collect, rent a bunch of Go Pros,
you can sync them with audio cues (clap sticks)
and edit together a control panel video.
if you could do it on a race track, you could also overlay
info from an App like Harry's Race Timer.
I look forward to seeing your results, your research
methods seem intense and and very interesting.
Are you also going to measure engine CFM intake and air temps?
measure any performance loss, if any?
Knowing as a racer that cool air is better than war air, will you be
adding other cold air intakes or simply sucking it from the engine
area at whatever the amibient temp might be in all conditions?
Michael Shortt
On Fri, Mar 18, 2016 at 11:35 AM, Stephen <steve at snclocks.com <mailto:steve at snclocks.com> > wrote:
I've been pondering for quite a while now the idea of putting a piece
of glass in the "window" in the deck lid behind the engine in 5332.
This would keep the engine from getting wet every time it rains and
would also keep from sucking grit and water off the road when the car
is running down the road.
Both seem like decent goals. Oh, and it would also make it more
difficult for someone to just reach in and remove 5332's dog-bone air
cleaner. OK - no one has taken it so far. But, hey, it would be all
too easy to remove.
Looking at the opening - it sure looks like the original intent was to
put in a window.
I have sent an e-mail to Tom Tjaarda (attached) asking his thoughts.
Hopefully he will respond.
In the interim, I put together a set of sensors so I could see what I
could learn about conditions in the engine compartment just inches in
front of the opening, to the right side of the dog-bone. The attached
photo shows the instrument cluster shot from inside the car.
I'm measuring air velocity through the rear window (vane anemometer)
Vacuum just in front of the window
Rotation of the a/c condenser fan (volt meter connected across the
motor, which acts as a generator when the fan turns)
Two of the above are fairly straight forward. The vacuum - not so
much.
When one talks about a vacuum, one is usually talking about a vacuum,
relative to ambient atmospheric pressure. So, if a vacuum gauge is
hooked up to your intake manifold, it reads the difference in pressure
between the atmosphere where the gauge is sitting, and the inside of
your manifold, where the hose from the gauge is connected.
So, what does one compare to in a moving car? The interior of the
car? That is what one would get if one puts a vacuum gauge in the cab
and routes the hose to the area in question. But, what does the
pressure (or vacuum) inside the car do with the car moving down the
road. Open the windows, your ears pop, and the pressure changes. Most
of us don't have an external air inlet (at least an intentional one) to
the cab except for the windows.
My solution is to use a fairly sensitive pressure gauge (a
sphygmomanometer - gauge used to read blood pressure. It reads in
inches of mercury. FYI, there are roughly 50 inches of mercury per
psi). I have connected the gauge with small-diameter plastic tubing to
a 200 ml stainless sample bomb. I wrapped the bomb in towels and
placed in a cooler to minimize temperature changes. See, the pressure
in the bomb will change by roughly .03 psi (1.5 mm Hg) for each 1
degree F change in temperature.
I then pressured up the bomb and let it sit overnight to stabilize. It
ended up at 280 mm. This is my "zero" at the then current barometric
pressure.
One has to view the pressure gauge as a delta-pressure device. It
shows the difference in pressure between the bomb (high pressure) and
the atmosphere around the gauge. So, if the reading on the gauge goes
up, the differential is increasing, which means the atmospheric
pressure is going down. As in a wee bit of a vacuum around the gauge.
Flip side, if the reading on the gauge goes down, well, there is less
differential between the 280 mm Hg in the bomb and the atmosphere
around the gauge, so the pressure is going up.
OK - that is complex.
While a gauge that can be read down to around 1 mm hg (0.02 psi) is
pretty sensitive, I suspect we are talking pretty minimal vacuum
levels. Preliminary testing suggested a reading of 272 mm Hg at 80
mph. The pressure around the gauge went up!
Huh. A lot to learn here.
I also noted that the volt meter did not show any rotation of the fan
on the a/c condenser. Need to make sure the wiring is ok. But, note,
the meter reads in mV, and, in my earlier testing, it showed voltage if
the fan turned at all.
The rubber for the new window shows up today, the window next
Wednesday.
My plan is to get a decent video and stills of the test instruments at
several speeds. Then, when the new window is installed, rerun the
test. I suspect the anemometer will still be valuable, since I suspect
there will be a lot of turbulence in the air in the engine compartment
even with the window in place.
Needless to say, having the window in place will complicate putting the
deck-lid back in place.
Stephen Nelson
---------- Forwarded message ----------
From: Stephen <steve at snclocks.com <mailto:steve at snclocks.com> >
To: <tjaarda at astranet.it <mailto:tjaarda at astranet.it> >
Cc:
Date: Tue, 15 Mar 2016 10:01:30 -0700
Subject: Pantera Rear Window
Good morning Tom. Whilst I am pretty sure you have no clue who I am,
being a member of POCA, I am aware of your contribution to the
Pantera. And I thank you for what you designed.
Being fairly new to these cars (3 years) I am still learning a lot.
One thing I have noted is the ability of my car to pick stuff up off
the road when I am driving at speed. I have found 1/4 inch gravel
behind the inlet manifold and was amazed to see high water marks on the
side of the rocker covers after a couple of hours driving in the rain
at 70 mph. Really quite neat actually, little wave pattern down the
sides of the rocker covers. Should have shot a picture.
None the less, I have queried the POCA forum about the absence of glass
in the opening behind the top of the engine. Folks indicated no one
had ever tried installing glass, and some voiced concerns about the
cars overheating if there was not lots of air flow past the engine.
So, am writing to see if I can get your thoughts on the lack of a
window in the deck lid and would appreciate any wisdom you can impart.
Whilst I have done a number of upgrades to 5332, including making the
engine a wee bit stronger, installing the best radiator and fans that I
could identify, and getting the a/c so it keeps the car comfortable, I
haven't really made any changes in the aerodynamics - like wings or
spoilers or front air dams. I suspect she would be a good test mule
for such a window and plan to start my investigation by figuring out
pressure (vacuum) levels above the engine at various speeds and also
the direction of rotation and relative rpm of the a/c condenser fan
(volt meter across the motor). My thought is to then do the same with
a window in place.
Any and all comments would be appreciated.
Stephen Nelson
[1]SNClocks.com
Click here to join one of our mailing lists [2]Contact Lists
Click here for our new [3]Hammered Dulcimers galleries
Click here for [4]my new blog on finding happiness in retirement
References
1. http://www.snclocks.com/
2. http://fs19.formsite.com/kagforms/form675003155/index.html
3. http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/About-Steves-Dulcimers/19824807_4sHGgj#1558377542_LKmkrT7
4. http://www.perfectoldman.com/
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www.michaelshortt.com <http://www.michaelshortt.com>
michael at michaelshortt.com <mailto:michael at michaelshortt.com>
912-232-9390
This email is protected by the Electronic Communications Privacy
Act, 18 U.S.C. Sec. 2510-2521, is confidential and may be legally
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-------------- next part --------------
Cameras are not the problem, it is lighting. Ambient is flat bright -
I had an led light shining on the gauges but not bright enough to
compensate for the sky in the background. Hopefully the next session
will be on a cloudy day, or I can run it at night.
With an engine that dyno'd at 480 hp, I am just not all that concerned
with power. I don't run the car all that hard, and suspect that inlet
air density will never be an issue.
I was surprised to see positive pressure in the compartment - won't
compensate for much temperature increase (vis-`a-vis air density) but
does raise questions on the impact of a belly pan below the engine -
increased rear lift? Now I am totally outside of my knowledge band.
Stephen Nelson
[1]SNClocks.com
Click here to join one of our mailing lists [2]Contact Lists
Click here for our new [3]Hammered Dulcimers galleries
Click here for [4]my new blog on finding happiness in retirement
From: Michael Shortt [mailto:michaelsavga at gmail.com]
Sent: Friday, March 18, 2016 8:57 AM
To: Stephen <steve at snclocks.com>
Cc: detomaso at poca.com
Subject: Re: [DeTomaso] Rear Window
Stephen,
I would simply borrow, collect, rent a bunch of Go Pros,
you can sync them with audio cues (clap sticks)
and edit together a control panel video.
if you could do it on a race track, you could also overlay
info from an App like Harry's Race Timer.
I look forward to seeing your results, your research
methods seem intense and and very interesting.
Are you also going to measure engine CFM intake and air temps?
measure any performance loss, if any?
Knowing as a racer that cool air is better than war air, will you be
adding other cold air intakes or simply sucking it from the engine
area at whatever the amibient temp might be in all conditions?
Michael Shortt
On Fri, Mar 18, 2016 at 11:35 AM, Stephen <[5]steve at snclocks.com>
wrote:
I've been pondering for quite a while now the idea of putting a
piece
of glass in the "window" in the deck lid behind the engine in
5332.
This would keep the engine from getting wet every time it rains
and
would also keep from sucking grit and water off the road when the
car
is running down the road.
Both seem like decent goals. Oh, and it would also make it more
difficult for someone to just reach in and remove 5332's dog-bone
air
cleaner. OK - no one has taken it so far. But, hey, it would be
all
too easy to remove.
Looking at the opening - it sure looks like the original intent
was to
put in a window.
I have sent an e-mail to Tom Tjaarda (attached) asking his
thoughts.
Hopefully he will respond.
In the interim, I put together a set of sensors so I could see
what I
could learn about conditions in the engine compartment just
inches in
front of the opening, to the right side of the dog-bone. The
attached
photo shows the instrument cluster shot from inside the car.
I'm measuring air velocity through the rear window (vane
anemometer)
Vacuum just in front of the window
Rotation of the a/c condenser fan (volt meter connected across
the
motor, which acts as a generator when the fan turns)
Two of the above are fairly straight forward. The vacuum - not
so
much.
When one talks about a vacuum, one is usually talking about a
vacuum,
relative to ambient atmospheric pressure. So, if a vacuum gauge
is
hooked up to your intake manifold, it reads the difference in
pressure
between the atmosphere where the gauge is sitting, and the inside
of
your manifold, where the hose from the gauge is connected.
So, what does one compare to in a moving car? The interior of
the
car? That is what one would get if one puts a vacuum gauge in
the cab
and routes the hose to the area in question. But, what does the
pressure (or vacuum) inside the car do with the car moving down
the
road. Open the windows, your ears pop, and the pressure
changes. Most
of us don't have an external air inlet (at least an intentional
one) to
the cab except for the windows.
My solution is to use a fairly sensitive pressure gauge (a
sphygmomanometer - gauge used to read blood pressure. It reads
in
inches of mercury. FYI, there are roughly 50 inches of mercury
per
psi). I have connected the gauge with small-diameter plastic
tubing to
a 200 ml stainless sample bomb. I wrapped the bomb in towels and
placed in a cooler to minimize temperature changes. See, the
pressure
in the bomb will change by roughly .03 psi (1.5 mm Hg) for each 1
degree F change in temperature.
I then pressured up the bomb and let it sit overnight to
stabilize. It
ended up at 280 mm. This is my "zero" at the then current
barometric
pressure.
One has to view the pressure gauge as a delta-pressure device.
It
shows the difference in pressure between the bomb (high pressure)
and
the atmosphere around the gauge. So, if the reading on the gauge
goes
up, the differential is increasing, which means the atmospheric
pressure is going down. As in a wee bit of a vacuum around the
gauge.
Flip side, if the reading on the gauge goes down, well, there is
less
differential between the 280 mm Hg in the bomb and the atmosphere
around the gauge, so the pressure is going up.
OK - that is complex.
While a gauge that can be read down to around 1 mm hg (0.02 psi)
is
pretty sensitive, I suspect we are talking pretty minimal vacuum
levels. Preliminary testing suggested a reading of 272 mm Hg at
80
mph. The pressure around the gauge went up!
Huh. A lot to learn here.
I also noted that the volt meter did not show any rotation of the
fan
on the a/c condenser. Need to make sure the wiring is ok. But,
note,
the meter reads in mV, and, in my earlier testing, it showed
voltage if
the fan turned at all.
The rubber for the new window shows up today, the window next
Wednesday.
My plan is to get a decent video and stills of the test
instruments at
several speeds. Then, when the new window is installed, rerun
the
test. I suspect the anemometer will still be valuable, since I
suspect
there will be a lot of turbulence in the air in the engine
compartment
even with the window in place.
Needless to say, having the window in place will complicate
putting the
deck-lid back in place.
Stephen Nelson
---------- Forwarded message ----------
From: Stephen <[6]steve at snclocks.com>
To: <[7]tjaarda at astranet.it>
Cc:
Date: Tue, 15 Mar 2016 10:01:30 -0700
Subject: Pantera Rear Window
Good morning Tom. Whilst I am pretty sure you have no clue who I
am,
being a member of POCA, I am aware of your contribution to the
Pantera. And I thank you for what you designed.
Being fairly new to these cars (3 years) I am still learning a
lot.
One thing I have noted is the ability of my car to pick stuff up
off
the road when I am driving at speed. I have found 1/4 inch
gravel
behind the inlet manifold and was amazed to see high water marks
on the
side of the rocker covers after a couple of hours driving in the
rain
at 70 mph. Really quite neat actually, little wave pattern down
the
sides of the rocker covers. Should have shot a picture.
None the less, I have queried the POCA forum about the absence of
glass
in the opening behind the top of the engine. Folks indicated no
one
had ever tried installing glass, and some voiced concerns about
the
cars overheating if there was not lots of air flow past the
engine.
So, am writing to see if I can get your thoughts on the lack of a
window in the deck lid and would appreciate any wisdom you can
impart.
Whilst I have done a number of upgrades to 5332, including making
the
engine a wee bit stronger, installing the best radiator and fans
that I
could identify, and getting the a/c so it keeps the car
comfortable, I
haven't really made any changes in the aerodynamics - like wings
or
spoilers or front air dams. I suspect she would be a good test
mule
for such a window and plan to start my investigation by figuring
out
pressure (vacuum) levels above the engine at various speeds and
also
the direction of rotation and relative rpm of the a/c condenser
fan
(volt meter across the motor). My thought is to then do the same
with
a window in place.
Any and all comments would be appreciated.
Stephen Nelson
[1]SNClocks.com
Click here to join one of our mailing lists [2]Contact Lists
Click here for our new [3]Hammered Dulcimers galleries
Click here for [4]my new blog on finding happiness in retirement
References
1. [8]http://www.snclocks.com/
2. [9]http://fs19.formsite.com/kagforms/form675003155/index.html
3.
[10]http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/Abo
ut-Steves-Dulcimers/19824807_4sHGgj#1558377542_LKmkrT7
4. [11]http://www.perfectoldman.com/
_______________________________________________
Detomaso Forum Managed by POCA
Posted emails must not exceed 1.5 Megabytes
DeTomaso mailing list
[12]DeTomaso at poca.com
[13]http://poca.com/mailman/listinfo/detomaso_poca.com
To manage your subscription (change email address, unsubscribe,
etc.) use the links above.
--
Michael L. Shortt
Savannah, Georgia
[14]www.michaelshortt.com
[15]michael at michaelshortt.com
912-232-9390
This email is protected by the Electronic Communications Privacy
Act, 18 U.S.C. Sec. 2510-2521, is confidential and may be legally
privileged. If you are not the intended recipient, you are hereby
notified
that any retention, dissemination, distribution or copying of this
communication is strictly prohibited. Please reply to the sender that
you
have received this message in error, then delete it. Thank you
References
1. http://www.snclocks.com/
2. http://fs19.formsite.com/kagforms/form675003155/index.html
3. http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/About-Steves-Dulcimers/19824807_4sHGgj#1558377542_LKmkrT7
4. http://www.perfectoldman.com/
5. mailto:steve at snclocks.com
6. mailto:steve at snclocks.com
7. mailto:tjaarda at astranet.it
8. http://www.snclocks.com/
9. http://fs19.formsite.com/kagforms/form675003155/index.html
10. http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/About-Steves-Dulcimers/19824807_4sHGgj#1558377542_LKmkrT7
11. http://www.perfectoldman.com/
12. mailto:DeTomaso at poca.com
13. http://poca.com/mailman/listinfo/detomaso_poca.com
14. http://www.michaelshortt.com/
15. mailto:michael at michaelshortt.com
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