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200 MPH What does it take?

ehpanteraehpanteraMember
What does it take to go 200 mph? Dan Jones provided these calculations to me based on the engine Dave Mclain built for me.



> How does the drag of the Pantera body look at 170MPH?

A publication called Style Auto published wind tunnel results on an early
Pantera. If I assume the coefficient of drag multiplied by the cross-
sectional reference (Cd * A) = 8.2035 , I get a decent match to the published
HP required numbers at 99, 118, 140 and 162 MPH. Extrapolating those to 170,
185 and 200 MPH, I get:

Vehicle Speed Drag RWHP required Calculated
(MPH) (lb) from Style RWHP reqd
Auto (drag only)
-------------------------------------------------------------------------
200 --- --- 447
185 --- --- 354
170 --- --- 275
162 556 238 238
140 426 159 153
Pantera 118 313 100 92
99 218 58 54
81 139 30 30

That's just the HP required to overcome the aerodynamic drag. If I assume a
3300 lbs weight with driver and fuel and calculate rolling resistance:

Enter velocity in miles per hour: 170.00
Enter vehicle weight (including driver and fluid weights): 3300
Cd * A = 8.2035
Drag due to aerodynamic drag (pounds) = 606.10
Drag due to rolling resistance (pounds) = 98.92
Rear wheel horsepower required due to aerodynamic drag = 274.76
Rear wheel horsepower required w/rolling resistance = 319.61

Enter velocity in miles per hour: 185.00
Enter vehicle weight (including driver and fluid weights): 3300
Cd * A = 8.2035
Drag due to aerodynamic drag (pounds) = 717.77
Drag due to rolling resistance (pounds) = 115.99
Rear wheel horsepower required due to aerodynamic drag = 354.10
rear wheel horsepower required w/rolling resistance = 411.32

Enter velocity in miles per hour: 200.00
Enter vehicle weight (including driver and fluid weights): 3300
Cd * A = 8.2035
Drag due to aerodynamic drag (pounds) = 838.89
Drag due to rolling resistance (pounds) = 135.27
Horsepower required due to aerodynamic drag = 447.41
Horsepower required w/rolling resistance = 519.55

> and changing to a 3.78 from a 4.22 gives about 6000rpm at 170mph on the shift
> from 4th to 5th. According to the dyno results the engine is making about
> 560hp at that RPM. Will that be enough power to allow the car to accelerate
> up to 180MPH/about 6500rpm? Also figuring we're probably dropping 50-75
> horsepower due to the exhaust system and altitude.

560 - 75 = 485 RWHP. Looks like 185 MPH would be no problem. Given that
he made 623 HP at 6800 to 6900 RPM on the dyno, it looks like 200 MPH might
even be possible, assuming the gearing worked out.

> Or can we go with a higher gear?

In addition to the different ring and pinions, there are taller 5th gears.
I have a 0.62:1 5th in mine. Assuming a 335/35/17 tire and a 3.78:1 final
drive ratio, the 0.62:1 5th would give 200 MPH at 6000 RPM but he wouldn't
have enough HP at that RPM. With the standard 0.705:1 fifth gear, 200 MPH
would be around 6830 which coincides with the power peak. There are also
0.655:1 and 0.642:1 5th gears if he wants to run 185 MPH at a lower RPM.

Dan

It doesn't come easily.
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panteradougpanteradougMember
In Bill Cosby's "200mph" he says, "I need a car that goes 200mph because I live 2 miles from work".

Gurney was "measured" at 220+ down the Mulsane Strait.

I want to say it was the black MkII but...

That was a 427. A 2,600 pound car. The drag is hardly better then a Pantera.

No one told him he didn't have enough horsepower to do it though. That was the difference.

No laptops then. You had to run the calculations through Ford's IBM system with the punch cards or use a slide rule that would tell you that 2x2 was about 4. Big Grin

Incidentally, the chase airplane couldn't keep up.

From what I saw your engine is going to peak at about 6850 and at that I would be VERY happy BUT I am the Mayor of Simpleton. I was appointed to that position. Unanimously. No election necessary.

I am leaving the over 200 thing to the F1 cars.
bosswrenchbosswrenchMember
180 mph= 3 miles per minute; be sure the road is long enough. For your Plan A, I suggest a front air-dam and a rear blade-spoiler. A naked front end gets light at around 120 and if you fix that with rake or an air-dam, the rear gets light above 170 and starts moving around. I'd also add a fire extinguisher, a 5 or 6-point harness and the best brakes I could find. A St. Christopher's medal and a full cage may help if Plan A doesn't work out....

As for power, Cosby's Cobra had a roots-blown 427 in it. Nor-Cal's Jr Wilson used a 427 Fontana in his Pantera to average 190+ over 92 miles at one SS pavement race. To go faster, Jr stuck a bored & stroked 574" Boss 429 in the same car. 900 bhp gave him 220 mph several times by radar. The engine cost him $80,000 over about 5 yrs of going real fast on U.S. highways. He blew 3 rear tires in successive years (including NASCAR Winston Cup tires) at over 200 mph. He also routinely emptied a 42 gal. fuel cell full of 110 octane in 92 miles. Was your name on the Powerball Lottery win list?
panteradougpanteradougMember
quote:
Originally posted by Bosswrench:
180 mph= 3 miles per minute; be sure the road is long enough. For your Plan A, I suggest a front air-dam and a rear blade-spoiler. A naked front end gets light at around 120 and if you fix that with rake or an air-dam, the rear gets light above 170 and starts moving around. I'd also add a fire extinguisher, a 5 or 6-point harness and the best brakes I could find. A St. Christopher's medal and a full cage may help if Plan A doesn't work out....

As for power, Cosby's Cobra had a roots-blown 427 in it. Nor-Cal's Jr Wilson used a 427 Fontana in his Pantera to average 190+ over 92 miles at one SS pavement race. To go faster, Jr stuck a bored & stroked 574" Boss 429 in the same car. 900 bhp gave him 220 mph several times by radar. The engine cost him $80,000 over about 5 yrs of going real fast on U.S. highways. He blew 3 rear tires in successive years (including NASCAR Winston Cup tires) at over 200 mph. He also routinely emptied a 42 gal. fuel cell full of 110 octane in 92 miles. Was your name on the Powerball Lottery win list?


I would recommend an ejection seat and not to worry about modifying the roof to accommodate it?
George PGeorge PAdmin.
Mark, 500 bhp should be enough to do 200 mph. Gearing is obviously important to match peak power with peak speed.

But the Pantera's aerodynamics are a problem. A former contributor to our forums was traveling 185 mph in his narrow body Pantera (based upon GPS) at which time it became air born, flipped up-side-down and left him severely injured in a pile of rubble alongside the road (in the Nevada desert). The car had no aerodynamic aides.

The Pantera needs an air dam up front that not only keeps air from flowing under the car, but also keeps air from getting under the nose. In other words it needs to be mounted forward, like the GT5 air damn (which isn't the most attractive air dam, but its effective).

I'm amazed that folks traveling that speed in a Pantera don't seem to resolve what to do with the air flowing through the radiator. So I guess it just flows below the car. Apparently its not important? I don't know what to tell you to do about that "air stream". But we all know the GT40 project flowed the radiator air out the front bonnet and over the car. If I were going to travel 200 mph I would do something to manage it, and keep it from going beneath the car ... (perhaps out the front wheel wells?) because I sure as hell wouldn't want to end up air born in my Pantera.

Unless you're traveling strictly in a straight line you'll also need to negate "lift" at the rear, the rear gets light too. This will require some sort of air foil shaped wing mounted in the back, up high in "clean" air. If all your down force is focused up front the car will pivot around the front wheels in turns, the car will oversteer. You have to balance down force front to rear.

Then oil cooling shall be needed for both the engine and the gearbox.

I don't know the details. The guys who do are the guys who race on big tracks. Many of them are members. I hope they'll chime-in and share their thoughts with Mark. Please.
ehpanteraehpanteraMember
I've been running SSCC & SORC for the last several years and have been picking others brains. I always have an air dam in front. I've been up to 165 with no problems with the rear being light. I picked up Mad Dawg's front hood and rear deck. I will be working on the rear spoiler prior to the upcoming race in Sept. It takes some planning to move up to the higher speed brackets. Going above 150 mph requires a lot more car prep. Roll cage, fuel cell, fire suppression, gearing. I have to work out the fuel cell issue, need more capacity. It takes a lot more gas to go fast.

Mark
panteradougpanteradougMember
quote:
Originally posted by JFB #05177:
how to you quantify that the car is getting light.

I would think having suspension spring length measurements would let you know


Well, in the front, if you turn the steering wheel, it has no effect. In that case the tires are off of the ground.

That is only momentary though. You back of the throttle just a tad and it comes down, sometimes feels like you hit a seam in the pavement.

Hopefully that moment where the steering "blacked out" caused no drama.

For me it PROBABLY meant I just wet my pants...or worse. You don't notice that at that moment.


In the rear, usually going into a turn and the car wants to tell you it wants to do the boog-a-lu. Sometimes to music?

Down the straits? Probably the deck lid wants to open and you might think it is rough pavement because of the chatter?

If you look at the Gp4 cars they had these silly elastic tie down handles added to the car to keep the decklid down and to reduce the twisting and rattling around.

The team drivers probably used these symtoms as rpm limiters back then?

As a group they are generally numb to this stuff and sometimes just raises a few yawns from them.

For me at 170, if the car is going to hop around and change lanes without moving the wheel, I just hope I remembered to wear my "Depends". I blame that on my parents. Strictly genetic I maintain? It's not my fault. Roll Eyes

The important thing is I TRY to overcome it? Cool


An interesting fact that I discovered with the car is that if you forget to latch the front hood, the car doesn't care. It doesn't bother the hood at all.

The rear? You will hear Frank Sinatra singing "come fly with me"? Maybe not. Could be just me from the concussion syndrome?
S speedunlimited (Guest)
When I first purchased my stock 1972 Pre-L DeTomaso Pantera, I took it up to 130-135 MPH & started to experience the dreaded "Front End Floooooooooat", knew what it was due to my pass experiences driving Exotics at mid to upper triple digit speeds & instantly backed off!

Thus I have to laugh at Pantera owners with stock cars & their erroneously inflated claims of 160++ MPH.
agustaboyagustaboyMember
I've had the Lambo up to 197 (Silver) LOL
https://www.youtube.com/watch?v=x_6_KwmxIqE

Getting up over 200 is actually quite challenging. If you are going to do it comfortably you need a lot of road.
Aerodynamics is a big factor at 185+ Many have showed up with their souped up Corvette thinking 200+ works for
them mathematically only to hit an air wall at 185.
I've done 189 in a 700hp supercharged 03 Viper

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agustaboyagustaboyMember
FYI the PANTERA was very stable and solid at 160. Granted if I run it again I will have a front air dam and seal the rear deck lid with a top plate for better AD.
and that was with a relatively stock 351C. (now with a spun Rod bearing hence the motor swap that I am doing.

Stock gearing.... 5th gear and there was still acceleration in 5th gear. Many will grab 5th or 6th gear at high speed and actually slow down.

Motor was turning 6,200 RPM 5th gear and it was absolutely topped out at 160.

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panteradougpanteradougMember
These are all speed numbers and issues that came up and were delt with by Shelby and Ford when they were involved in GT International racing in the 60's.

It is one of the reasons Shelby built the Cobra Coupe. 150mph in the roadsters and 175 in the Coupe.

The GT40's apparently were always more slippery in the air but needed down force corrections?

That was Phil Remingtons specialty.



Personally my opinion on the Pantera is that 180 to 185 is the wall.

There simply are too many other considerations like air under the car to be delt with without making a Pantera into a past tense, "was a Pantera".

I completely disagree with Carrol Smith on the subject of the Pantera. If he rephrased the comment as "there are EASIER cars to race than a Pantera", then who could argue? Not me.


I completely understand where you guys are at with the 200 thing.

To me though it is merely an academic exercise in futility.

So you get 200? So. Then what?

'Mad Dog' did. Is he retired now?



Oh, and I was a passenger in Eber's CSX3036 at Pocono. The car WAS turning 8,300-8,400 rpm down the straights AND the speedo (which was right in front of me) was saying 178 to 184. Single Holley. 427ci. No V10 necessary. No spoilers no nothing and it had more left.

The air kept catching under my helmet and pushing my head back.



While I am on this thought of completely sidetracking this thread, I need a calculation of down force for the rear of the car.

I need it translated into the angle the wing(s) need to be. I'm presuming 120 degrees and the total surface area needed to keep the ass down, or at least a surface area per pound of down force?

My thought is to attach 2"x2" minnie clear lexan spoilers to the edges on my deck louvers (Venetian blinds -see pic).
I can't calculate that. My slide rule is broken, my calculator is out of batteries, and my nanny confiscated my Crayolas?

Anyone?

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stevefstevefMember
It was 1995, the convoy to Las Vegas was all lined up. Great opportunity to "open it up" The ride and feel was SMOOTH, 110 ,120, 125... beautiful... 128 ...... I felt like I now had power steering.... obviously the front end was lifting.... Great memories, I no longer have a desire to exceed 100+ thank you...Smiler
S speedunlimited (Guest)
quote:
Originally posted by Steve F:
It was 1995, the convoy to Las Vegas was all lined up. Great opportunity to "open it up" The ride and feel was SMOOTH, 110 ,120, 125... beautiful... 128 ...... I felt like I now had power steering.... obviously the front end was lifting.... Great memories, I no longer have a desire to exceed 100+ thank you...Smiler

ahhhhhhh...A Sound Voice of Reason & True Application of Experience!....You'd better watch that Steve Cheers Interested to note I ALSO experienced the same "Power Steering Effect" at the relatively SAME basic speed range!..

Makes me wonder where ALL these stock 160MPH Detomaso Panteras come from??!!...
must be the Secret High Performance DeTomaso Pantera factory...under the code name..."Cone of Silence"!

https://www.youtube.com/watch?v=vsNR9FnxOdY

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