[DeTomaso] Gr4 Pantera at Le Mans video / aerodynamics at high speed
Larry Stock
larrys at panteraparts.com
Wed Feb 3 19:14:22 EST 2021
We make and sell a NASCAR Type rear blade spoiler, we also developed a rear center diffuser, and we have a race lipped front air dam that will develop about 500 pounds of front down force at 150 MPH, plus the we then added a underside wing to go under that spoiler. (at the Pony Express we got her airborne going over a bridge for about 175 feet, we actually came down slightly nose heavy at 155 mph) With another 7 weeks of foam and fiberglass underside shaping and side skirts we were getting about 4700 pounds of down force from shaping the underside with only the blade rear spoiler above the centerline. The side skirts made all the difference in the world. At Pahrump’s 2.4 mile technical road course we shaved off 6 seconds with and without the side skirts with all the other enhancements afore-mentioned installed. So if you are running a Silver State for speed, no skirts for minimum drag, for a Road course run the side skirts to suck it into the pavement. Since we were creating so much down force we actually had to set the chassis up with Positive Camber to get the tires to heat evenly. We were actually sucking the Pantera down about 3 inches at 140 MPH. We measured less than ¼” of clearance left at the rear crossmember by the amount of fiberglass left on our rear diffuser. We were pulling up the asphalt pebbles, depositing them on top of the deck lid, so much so I had to repaint the deck lid 2 or 3 times as they would pile up in front of the rear blade spoiler and just grind away the paint.
Larry
From: Rich Hoppe <richbhoppe at gmail.com>
Date: Wednesday, February 3, 2021 at 2:38 PM
To: Larry Stock <larrys at panteraparts.com>
Cc: Dan Courtney <dan at excaliburre.com>, "DeTomaso at server.detomasolist.com" <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Gr4 Pantera at Le Mans video / aerodynamics at high speed
Larry
I ran the pizza car with a front spoiler or splitter 165 mph at silverstate for the last 20 miles straight without a problem.
I think I hit that speed again at the texas world speedway on the main straight.
The car is pretty stable at that point, but I would like to buy a nascar rear blade if someone has one.
I really dont want to find the aero limit by trial and error.
At Apex motor club track that I run on they put a chicane on the long straight that holds my speed to maybe 140-150.
They may have a day where they take the chicane out and let you go down a 3800 ft straight.
I think I could hit at least 180mph.
When I run it out in forth gear it hits about 167mph at peak HP 8000 rpms.
Then there is 5th which has been changed to the taller gear in the transaxle.
I have never shifted to 5th and let it climb yet the road is always too short.
So I am not sure when I really need the blade but the situation will happen sometime.
Rich
On Wed, Feb 3, 2021 at 3:15 PM Larry Stock <larrys at panteraparts.com> wrote:
At speeds beginning at 120 the US DOT raised ride height Pantera's front end will start to float. If you lower the Pantera to Dallara's originally designed ride height with the A-Arm's flat and parallel with the road surface, and with a short and well clearanced GTS fiberglass or a short blade type front spoiler, we can get to 155 MPH when it's all you can do is hold on to it in two lanes of traffic as I experienced at the Silver State. With a group 4 or group 5 front spoiler you are good up to about 180 MPH when the roof and deck lid design will begin to lift the roof and unload the rear of the Pantera so you need a rear spoiler and diffuser to break up the rear lift to hold it down. A wing will do the same, but you probably won't have the HP to be able to get there with most wings, and it then it will become rear heavy and unbalanced. So if you were to get air under the front end where you end up like Junior Wilson and/or the Audi Prototype car at Le Mans 10 years ago, going a spectacular 70 feet in the air going end over end until final impact. A simple Nascar type blade spoiler to break the lift without adding much drag is about all you need. Mike Cook told me with the aluminum front hood skin, that at about 185 MPH, it was pushed (crushed inward) in from the frontal air pressure just above where the vented hood vents would have been. So at speed, the typical radiator front hood vents would probably be putting more air under the Pantera aero design, further destabilizing it. Now let all that data settle in.
Larry Stock
On 2/3/21, 1:20 PM, "detomaso-bounces at server.detomasolist.com on behalf of dan at excaliburre.com" <detomaso-bounces at server.detomasolist.com on behalf of dan at excaliburre.com> wrote:
Regarding the aerodynamics at high speed, when Cook Sr. built "The
Beast" in '71 he used rubber thongs on the vented fiberglass front deck
lid, which allows it to float at high speed.
On the rear deck lid he installed a huge stainless steel wing, like
something off a B-52.
The wind didn't appear to help enough.
On one infamous Silver State Challenge the rear of "The Beast" was
lifting above 170 mph.
About 1/2 way through my run "The Beast" stabilized and started holding
the road again.
After arriving at the finish line someone asked me what happened to my
rear deck lid (now fiberglass and without the B-52 wing) and I realized
it was gone.
I'm guessing it flew off at the same time the car stabilized.
Dan
Dan Courtney
La Jolla, CA
(858) 337-7019 cell
Dan at excaliburre.com
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-------------- next part --------------
We make and sell a NASCAR Type rear blade spoiler, we also developed a
rear center diffuser, and we have a race lipped front air dam that will
develop about 500 pounds of front down force at 150 MPH, plus the we
then added a underside wing to go under that spoiler. (at the Pony
Express we got her airborne going over a bridge for about 175 feet, we
actually came down slightly nose heavy at 155 mph) With another 7 weeks
of foam and fiberglass underside shaping and side skirts we were
getting about 4700 pounds of down force from shaping the underside with
only the blade rear spoiler above the centerline. The side skirts made
all the difference in the world. At Pahrump's 2.4 mile technical road
course we shaved off 6 seconds with and without the side skirts with
all the other enhancements afore-mentioned installed. So if you are
running a Silver State for speed, no skirts for minimum drag, for a
Road course run the side skirts to suck it into the pavement. Since we
were creating so much down force we actually had to set the chassis up
with Positive Camber to get the tires to heat evenly. We were actually
sucking the Pantera down about 3 inches at 140 MPH. We measured less
than 1/4" of clearance left at the rear crossmember by the amount of
fiberglass left on our rear diffuser. We were pulling up the asphalt
pebbles, depositing them on top of the deck lid, so much so I had to
repaint the deck lid 2 or 3 times as they would pile up in front of the
rear blade spoiler and just grind away the paint.
Larry
From: Rich Hoppe <richbhoppe at gmail.com>
Date: Wednesday, February 3, 2021 at 2:38 PM
To: Larry Stock <larrys at panteraparts.com>
Cc: Dan Courtney <dan at excaliburre.com>,
"DeTomaso at server.detomasolist.com" <detomaso at server.detomasolist.com>
Subject: Re: [DeTomaso] Gr4 Pantera at Le Mans video / aerodynamics at
high speed
Larry
I ran the pizza car with a front spoiler or splitter 165 mph at
silverstate for the last 20 miles straight without a problem.
I think I hit that speed again at the texas world speedway on the main
straight.
The car is pretty stable at that point, but I would like to buy a
nascar rear blade if someone has one.
I really dont want to find the aero limit by trial and error.
At Apex motor club track that I run on they put a chicane on the long
straight that holds my speed to maybe 140-150.
They may have a day where they take the chicane out and let you go down
a 3800 ft straight.
I think I could hit at least 180mph.
When I run it out in forth gear it hits about 167mph at peak HP 8000
rpms.
Then there is 5th which has been changed to the taller gear in the
transaxle.
I have never shifted to 5th and let it climb yet the road is always
too short.
So I am not sure when I really need the blade but the situation will
happen sometime.
Rich
On Wed, Feb 3, 2021 at 3:15 PM Larry Stock <[1]larrys at panteraparts.com>
wrote:
At speeds beginning at 120 the US DOT raised ride height Pantera's
front end will start to float. If you lower the Pantera to Dallara's
originally designed ride height with the A-Arm's flat and parallel
with the road surface, and with a short and well clearanced GTS
fiberglass or a short blade type front spoiler, we can get to 155
MPH when it's all you can do is hold on to it in two lanes of
traffic as I experienced at the Silver State. With a group 4 or
group 5 front spoiler you are good up to about 180 MPH when the roof
and deck lid design will begin to lift the roof and unload the rear
of the Pantera so you need a rear spoiler and diffuser to break up
the rear lift to hold it down. A wing will do the same, but you
probably won't have the HP to be able to get there with most wings,
and it then it will become rear heavy and unbalanced. So if you were
to get air under the front end where you end up like Junior Wilson
and/or the Audi Prototype car at Le Mans 10 years ago, going a
spectacular 70 feet in the air going end over end until final
impact. A simple Nascar type blade spoiler to break the lift without
adding much drag is about all you need. Mike Cook told me with the
aluminum front hood skin, that at about 185 MPH, it was pushed
(crushed inward) in from the frontal air pressure just above where
the vented hood vents would have been. So at speed, the typical
radiator front hood vents would probably be putting more air under
the Pantera aero design, further destabilizing it. Now let all that
data settle in.
Larry Stock
On 2/3/21, 1:20 PM, "[2]detomaso-bounces at server.detomasolist.com on
behalf of [3]dan at excaliburre.com"
<[4]detomaso-bounces at server.detomasolist.com on behalf of
[5]dan at excaliburre.com> wrote:
Regarding the aerodynamics at high speed, when Cook Sr. built
"The
Beast" in '71 he used rubber thongs on the vented fiberglass
front deck
lid, which allows it to float at high speed.
On the rear deck lid he installed a huge stainless steel
wing, like
something off a B-52.
The wind didn't appear to help enough.
On one infamous Silver State Challenge the rear of "The
Beast" was
lifting above 170 mph.
About 1/2 way through my run "The Beast" stabilized and
started holding
the road again.
After arriving at the finish line someone asked me what
happened to my
rear deck lid (now fiberglass and without the B-52 wing) and
I realized
it was gone.
I'm guessing it flew off at the same time the car stabilized.
Dan
Dan Courtney
La Jolla, CA
(858) 337-7019 cell
[6]Dan at excaliburre.com
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References
1. mailto:larrys at panteraparts.com
2. mailto:detomaso-bounces at server.detomasolist.com
3. mailto:dan at excaliburre.com
4. mailto:detomaso-bounces at server.detomasolist.com
5. mailto:dan at excaliburre.com
6. mailto:Dan at excaliburre.com
7. mailto:DeTomaso at server.detomasolist.com
8. http://server.detomasolist.com/mailman/listinfo/detomaso
9. mailto:DeTomaso at server.detomasolist.com
10. http://server.detomasolist.com/mailman/listinfo/detomaso
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