[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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-- 








Michael L. Shortt
Savannah, Georgia
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
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

-------------- 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
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     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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