Ground Effects

No net search yet for existing underbody ground effects kits since I'm pretty sure this is still way ahead of it's time in the aftermarket. I'll search that later. It would be nice to find something very compatable off the shelf and adapt it to fit my Pantera....

The plan is to start with templates of paper, then cardboard, aluminum, then fiberglass. The aluminum prototype will then serve as the slave mold for the production fiberglass molds. Fiberglass will be version-1 target goal for limited production prior to Vegas 2006 and full production by the Track Event 2006. After I get back from Vegas 2005, of course.

I'll have to study the front, side and rear ground effects from Saleen, etc. to come up with the best guess for what the best rear design will be. Maybe need to watch a Formula One event in a week or so to study theory in design practice some more. And anybody seeing Le Mans will have the opportunity to see different rear ground effects deflectors, too.

This is funny. I write these topics and people read them, and there's no responses. So, I just keep developing different ideas and topics and people keep reading them, but don't respond. So, this tells me that you're interested, and so I'll keep developing the topics ideas. You can respond if you like though.... Sort of feels like I'm crazy and talking to myself, only like it's different from the homelsss people who yell at cars passing by, you folks are stopping to 'listen' to me talk to myself.... So here's the update:

I did a search "ground effects upgrade kit" and there's a bunch of manufacturers with 'upgrade kits' but not 'the right stuff' because all the available products are for 'show' with protruding externally visible body panels, spoilers, body widening or lower front spoiler stuff. Etc. That's of no interest to me. Let me discuss 'ground effects' theory a little more with you so you get an idea of what I'm doing, or, going to do... and why.

I've been watching Formula One, CART, IRL, and Le Mans, GTP, etc. for 20 years. Over that time, the TV commentators have had the opportunity to show under trays that came off the racing machinery and explain the theory of downforce a/k/a ground effects. Also, when the santioning bodies, like Formula One and Bernie Echelstein (sp?) make 'rules changes' every year to get the cars to slow down, the TV coverage gives nice explanantions and show graphics or side-by-side footage of changes to last year's cars and this year's cars.

Let me give you the bottom line first, so I don't lose your interest. I plan to bolt on some flat aluminum panels to the under side of my Pantera and do a 'side-by-side' comparison in a 'scientific' way. I'll attempt to do Vegas 2005 with a G-Tech Meter so I can download data for stock Pantera mode, with lateral (cornering) and forward (stopping) g-force measurements. I'm thinking basically 3 panels should do the job. Front panel covers the gap from the under side of my GTS spoiler to the back lip of the front valance. This smoothes out the air flow under that area and should produce more 'vacuum' or lower pressure from the rear of the radiator. The second panel is still in concept-debate mode, but it will either cover the entire center section of the under side of the car or just the tunnel housing the water tubes. I may have to have some small tabs or mounting brakets/bolts spot welded to make the attachment secure. The third under tray will go under the engine and transmission all the way back to the rear sway bar brackets mounting position (where those De Tomaso logos go with the nice aluminum sway bar mounts.

To get any measurable increase (Vegas 2006) in downforce, the car must be lowered. F-1 cars are about 0.5 to 1.0" off the ground. They used to have under trays with large indentations resembling airplane wings cross sectioned as if viewed from the inside of the airplane wing. The theory is simple. The airplane wing creates 'lift' and the opposite is true for ground effects where the air passes on the 'opposite side of the airplane wing'. The fast flowing air under the car expands into the cavity creating lower pressure, or down force. This worked so well on Formula One cars that they generated enough down force to be able to theoretically drive upside down at speeds over 100 mph. Is this making sense to you? So, the cars got really fast in the corners and they decided to eliminate the 'inverted wings' or indentations in the under trays to slow the cars down. Now Formula One mandates flat under trays. Why does this work? I think it's Bernouli's Law, but if you took a chemistry class in high school or college, maybe you remember a simple laboratory piece of equipment that you may have used in the lab experiment for the week. The device was a plastic tube that attached to the water faucet and had a small 90 degree tube fitting attached half way down. You attached the rubber 'suction hose' to the 90 degree fitting and turned the water on. As the water flow increased, the suction from the tube increased, and did the 'sublimation' experiment or whatever it was. It just worked to generate suction as it was intended to do, that's all I can tell you and that's all you need to know, i.e. enough science class for today. What it means is fast rushing air in a smooth flow will generate 90 degree suction, pulling the car and ground together. Ground Effects-101

This year's changes to F-1 cars mandate that the under trays extending towards the rear wheels have to come inboard more, to reduce the ground effects. The front wings are also required to be higher off the ground to reduce downforce or 'ground effects' and together they reduce downforce by 20% from last year. In pervious years F-1 rules chances also required raising the car higher off the ground to reduce ground effects. What this means to us is twofold. 1) the lower the car, the greater the downforce generated. 2) Flat bottom cars produce downforce and it's going to be pretty simple to design and install a three piece gound effects under tray kit for the Pantera. Thirdly, and implied is the greater the speed, the greater the downforce generated.

Downforce is a concept different than weight ('mass" is the scientific word). For example, if you're producing 500 pounds of downforce at 100 mph, going into a turn, this is a vector force that pulls the car downward only, not outward. Which is much different than 'weight' or 'mass' because the same car without ground effects and 500 pounds more of weight, will generate a vector force in a lateral direction, towards the outside radius of the turn. Weight of 500 pounds pulls the car that much more towards the outside of the turn, and the g-force meter would show a decrease in lateral g-loading on the car, and also on your body. An effective ground effects under tray would have the opposite effect on the readings of the g-force meter, the car would negotiate the turn faster and the g-forces on the car and your body would be higher. The car is safer to drive at higher sppeds around the corners, and the downforce also holds the car down, similar to weight, when it comes time to apply the brakes at high speed for the hairpin turn at the end of the straightaway. Weight creates inertia, whereas downforce creates grip without increasing inertia. Is this sort of making sense to you?

So the Pantera without ground effects will produce some turbulance of air rushing underneath the car at speed, causing lift. The Pantera with ground effects will produce airflow in a single direction, creating suction at a 90 degree angle to the direction of the airflow. The faster the airflow, the greater the ground effects downforce generated. The lower the car sits, the greater the downforce generated.

It's important to be able to apply the brakes or get response from the steering wheel at speeds over 100 mph, which these beasts can easily accomplish. This is what I call 'handling' and it's for functional purposes, and doesn't even have to be visible from the exterior. It's not for looks at all. And it can be done to any car.

So, I'm visualizing the rear Pantera under tray attaches to the frame, but extends further outboar toward the tires, with enough clearance of the lower A-arms, and the closer to the rear tire, the more downforce. This is going to have to be securely mounted and it will have to be about 3/16" thick aluminum for rigidity in this back under tray. There will still be plenty of air flow up through the openings in the wheel wells to feed the engine requirements and cool the headers and exhaust.

I'll get around to the other stuff that will make it go closer to 200 mph after I sort out these safety and handling issues first. That other 'stuff' is going to be a lot more expensive though, like horse power and transmission gear ratio modifications and/or a higher rpm-redline engine.

Class dismissed! Thanks for your interest in this subject. VFI

VFI - Yes, I do read your posts. As I've gotten older I think I've developed ADD so it may take me a couple of times to come back and finish reading them. But I do read them.

Please continue. Your posts are both informative and entertaining.

I think DOES200 has a belly pan. Pretty neat. Maybe the owner can post pics.

Thanks, PNATERA1580! If DOES200 has a belly pan, now we know why and what it's for and how it does what it's supposed to do.

The most cost efficient, scientific/engineering way to measure what kind of results a ground effects underbody tray does is with one of these meters:
http://www.gtechpro.com/ about $250
http://www.racepak.com/ about $800

Jim, you must have an interest in this ground effects stuff, 25 years on the track and all. If you go ahead and start experimenting and measuring results, will you please post too? Thanks.

You can skip reading this Off Topic Note if you've finished your taxes already. [[Side note to explain the reason I keep jumping on the web: Guys, I'd rather do anything than compile my taxes. I've got a stack of receipts in a folder 3" high that have to go into a Schedule SE. It's like writing a term paper every year for me, and I cloister myself inside like a monk until I get it done, then I can officially begin Springtime! I'm going to take a nap instead and see if I can force myself to do that task later. Anything but that.... So much energy I channel into avoiding that every year.... Yuk! There's got to be something else I can do to "productively" avoid doing my task-at-hand, Yuk! Please ask some question or post a new topic or something.... But I can save enough by doing it myself to offset the cost of going to the 2005 PCNC Vegas Track Event, so I'll Nike, and 'just do it'. I always feel much better when I get that gorilla off my back every year. Their paid, but the forms, man that's a cumbersome task, I hate it. I'd rather gripe about doing it than do it. OK, adios then.]]

It occurs to me that I need to express concern again about doing this downforce-ground effects upgrade the right way. If you don't get it right and you do your first (1st) road test at top speed, or even at lower than top speed and your underbody ground effects tray fails, it could be mortal to you. And at speeds like anywhere from 150 to 200 mph, with the scenario of the underbody tray peeling off from wind force or pulling thru some cheezy rivets you installed it with, it will kill you. You won't get a second chance. At a minimum, it could puncture a tire, which at those speeds, may be your last flat tire ever!

The right way to proceed is to gather as much information as you can, then test in a controlled environment, like a track. The benefit of passing safety inspections is just what the reasonably intelligent guy would do, He would practice due diligence in designing and safety testing. He'd exercise caution during experimentation. He'd gradually test at lower speed, for only a lap or two, then pull into the pits and make sure everything is still tight and snug, with no visible signs of failure, or bending, or attachment points pulling through. If the technical safety inspection guys say, no way, then it's no way. Nobody is in favor of seeing somebody get hurt.

Shake downs and testing should be done at the track. I think road courses are preferred for this, since there's room for running off the track in case of catastrophic failure, and very little opportunity to go at maximum speed (for very long, anyway). Only after more testing, and more knowledge and experience are gained, should attempts at open highway events be considered.

There's an Open Highway Event at Big Bend, Texas, in April, just prior to the 2005 PCNC Vegas Track Event. There's also the Silver State Open Highway Event in Nevada every year. So there's an opportunity to go as fast as you can, in a safety controlled, sanctioned, lawful way. And always let your instincts guide you. If you feel fear or loss of traction and sense the car is floating, then slow her down! That's your survival instinct talking to you, and it is warning you to slow down and inspect the set-up again. Listen and obey the survival instinct calling to you from your stomach.

It's probably only very experienced, safety oriented enthusiasts who do these open highway, top speed events, so I'm not too concerned about them not doing proper research and development for underbody ground effects. They are saavy and in the loop. I may just go and watch one of these events before proceeding any further. I'd like to ask questions about this topic, to get more information, and hook up with them to develop this idea further. Maybe they can point me to research that's already been performed, that would be cool.

I worry that somebody doesn't do it with much attention to safety and does their experimenting on open highways somewhere. That would not only be dangerous to themselves and others, but seriously unlawful, and there's many ways to pay too steep a price for a little fun and excitement.

Some potential pitfalls in the quest for downforce include the ground effects tray being too efficient and pulling through the bolt holes and flying loose. There's another possibility that the overly efficient ground effects generate too much downforce and break a suspension member. There's a possibilty the wind catches it and tears it partially loose at high speed, creating just the opposite reaction: the front of the car goes air-borne and the car flips over backwards at speed. You may have seen hydrofoil Formula One boats do that (flip over backwards) when they catch a small rogue wave at high speed. 150 to 200 mph is the equivalent of a violent hurricane or tornado.

But, if the technology is properly developed, tested, and installed, it actually will make the Pantera stop in shorter distances from very high speeds and be more controllable as well. So, the opposite edge of the sword from danger is safety. These beasts of machines can be made more controllable and driven with a greater margin of safety, at closer to their full potential. That's what we all want.

The development and application of technology is what truly fascinates me, and it's great to see you guys are intereseted in this stuff also. Let's just do it right, so the benefits accrue without the risks turning fatal. OK? Thanks.

'Professor' VFI wonders if his on-line class is even reading his lectures, but there'll be a test in the end. I don't want any of you failing the test, OK? No fatalities! These topics are meant to inspire, not promote dangerous behavior. Are you thinking about it yet? I'm sure you are, but a little more in a controlled way than you were before. Good.

I found a pic of does200's belly pan

http://community.webshots.com/photo/61629084/76941880miYkGX

it really looks nice, very nice.

Thanks Professor JohnnyAlki, I didn't know know we'd have a visiting professor with us today. Thanks again Professor JohnnyAlki for bringing great visual-aides to our R&D investigation today.

Professor DOES200, where'd you get those ground effects? You can maybe see that approximately 165 of us want to know more about your ultra-sleek set-up. That 165 count is at 8:40 AM, Sunday, March 13, 2005, a meer three days or so into this topic. It's like, Ooops again, there's always someone more knowledgeable about these matter than me! I'm thrilled to get such promising results. Shocked, actually....

Will you guys educate me some more,
por favor?

You might like to look at Goran Malmberg's website. He has played with Pantera Aerodynamics.
http://hem.passagen.se/hemipanter/

Jim Hall and Hap Sharp are my heros for ground effects innovations. Only problem is every time they developed something the sanctioning bodies made rules against their developments. Try:
http://www.sandcastlevi.com/racing/chaprral.htm

Thank you Professor Jim. I read Professor Goran Malmberg's R&D Manual you refered us to with keen interest and must comment. Professor Goran Malmberg's applied downforce theory for his Pantera's center section, underbody panels, fabricated from the interior of his Pantera, appeals to me as being absolutely the right approach. Professor Goran Malmberg's front ground effects aluminum underbody tray looks securely attached and very well designed. I note how he attempts to get the maximum area of coverage, while cutting out just the minimum aluminum to make room for his wheels to turn into.

I agree that the Pantera creates a vacuum effect in the engine compartment, and wonder why there are no rear Pantera underbody trays in application on Pantera's at present.

I want to add that I think Professor Goran Malmberg is way more advanced than I on this topic and would like to invite him to make a presentation to our 'virtual classroom' Pantera Research Seminar: Pantera Under Body Ground Effects.

I saw Professor Goran Malmberg measures ground effect in milimeters of water. This tells me he is using a manometer, which can easily be purchased for cheap, to get those readings. Manometers are also available in mercury, but smaller measurements can be made with mm of water. Then there is a conversion factor to tell what the "pounds of downforce" really are on the front or rear. So, now I'm aware there is an even more inexpensive way to 'measure' downforce.

Thanks to all contributing 'visiting Professors'.

I must review the other research material Professor Jim refered us to. It's a shame the santioning bodies prevent much further R&D in some of these areas with rules changes.

Now get back to your taxes. I just mailed my bundle off to the accountant today.

I took a long nap Saturday and crashed the tax project hard Saturday eveninig, so by the time the sun came up Sunday morning, all I had left was Schedule "A" (Itemized Decuctions) and there's a new standard deduction for sales tax. I have to read that and run the numbers both ways, then do the final 1040 Form. Under 2 hours left to go. I always did term papers like that too, and sometimes Pantera projects.... Get the momentum going and continue thru to completion, then fix the sleep cycle later. Yep, I feel good now, the gorilla has been caged again, off my back for another year. I'm thinking I may want to learn how to weld again to do some underbody Pantera modifications, done from the interior of my Pantera. I'm getting pumped up about it already, and it's next year's project! I don't get pumped up about the tax forms until the pressure's on, then I slam the project thru to completion. Not fun. 13 hours into the tax project and only 2 left to go. Springtime is here now I finished, but it snowed today and dropped to the 20's after 70 degrees and sunny on Saturday. I won't misss a day like that again this spring!

Back on topic. Inspired by Goram Malberg's approach to measuring ground effects, I looked up the manometer in an old chemistry book. Now, I'll explain how to make a simple, inexpensive manometer to test downforce created by ground effects.

Take a clear plasic hose, any diameter, and seal up one end with a plug. pour water into it and make a "U", then flip the dry end of the monometer over and back down, letting the water spill out. Mount the manometer on a piece of wood and fix it stationary on the inside of the Pantera, visible while driving. Take the other end of manometer tube, the dry part, and run it to the underside of the Pantera where the measurement of vacuum is to be taken, or measured. When the vacuum measurement is taken while driving, the "inches of water" will be the length of air created at the end of the manometer which is sealed, or the distance the other side of the 'water column' goes up with the application of vacuum. The manometer can also measure "inches of water" for positive air pressure, and the column of water will just go the other direction. Water is used instead of mercury because it is safer, free, and readily available. It just travels greater distances up or down the manometer. The "inches of water" is a force of vacuum or air pressure which can be translated into pounds of downforce, depending on the surface area of the ground effects device: rear wing, underbody panel, etc.

I e-mailed Professor Goram Malmberg and asked if he'd like to contribute to this topic and to please keep his website updated with the latest information he has to share. Any other contributions are also welcome, and invited.

Hi Goram,
I am wondering why you do not mention a rear ground effects underbody panel for the Pantera. I asked the question about Pantera ground effects in Pantera International Bulletin Board's (PIBB) Forum "Technical Advice and Questions" at the end of last week, 3/10/05, and there has been 398 people viewing the question and answer session in only 4 days. I'm "veryfast italain" on the PIBB and Ron Norman, in real life, living in Albuquerque, New Mexico, USA.

So, my idea about the rear underbody ground effects aluminum pan is being asked there, and I thought I should ask you if you would like to join the PIBB topic, as I've seen you do in the past. It will be nice for me to be able to learn more, and many others are interested too. Please join the PIBB discussion topic if you'd be so kind. I also read your Pantera International article on tire sizes a while back. Recently I wrote an article published in Pantera International too. Please see it on page 15, Summer 2004, Pantera International, if you like.

http://pantera.infopop.cc/eve/forums/a/tpc/f/6450045562/m/8540068223

Thank you for the very detailed and informative website. You may see more visitors son because there is a link to your website in the topic: Ground Effects on PIBB.

Maybe it will be interesting to develop this idea further, and we will certainly be checking your website in the future as you develop your Pantera even further. I'm inspired by your project. "Way to go", Goram.

Best regards,
Ron

Ron, nice to hear from you.

Well, I have had some troubble connecting up to the board, and also asked Dave for assistance.
But it failed and I hasent tryed since then. May check it up again. I do have an article comming up
in the PI magnext issue about shock absorbers. And another one about spring and bar settings
for race cars, for futher issues.

I havent bee sleeping when it comes to rear diffusser;s. But the big problem is the Pantera rear
layout that dosent easely accept an diffusser. First, the frame where the rollbar is fasten, is right
in the way for the expansion roof. Even the A-arms is a bit of a problem, espesialy if rebound is
extensive. We must also se to that the engine compartment get some cooling air if the entire
underside is blocked.

If you look at the underside of the car, the cockpit floor is not flat. Neither is the rear frame "inline"
with the floor. We will run in to som strange stepped underside which is not very good. I was planning
on making a whole new lower rear frame, to get it where it out of the way. The front part all the way to
the engine is allready quite functional, which is the area to start working with.

The rear hood has a flat floor which is feed with air from under the car, comming out the "fake window".
Its a turbulent area, and the lack of "wingshape" due to the hood -flat area does not create any rear lift.
However, the diffusser must be made to work together with all these conditions. Ok, a lot guesswork
here, but things to take in to account. And a few things mentioned I also know for sure.

Whatever way we look at this problem, it is NOT a fabrication bolt on part. If not som sort of
"semi-functional-bling stuff" is asked for. But I dont involve myself in such things.
Allright, we will see what to come up with.

Regards
Goran Malmberg

Class Experiment,
Applied Pantera Downforce Theory.

Doesn't the scientic principal say something like: get this idea, make a hypothesis (or theory), test it and see what happens? That's what I remember.

My 1973 Pantera with only a 1984 Euro GTS spoiler up front is telling me do some tests. First, get a bunch of manometers, or just a bunch of clear tubes taped or twist tied onto a foamboard, with markings every two inches in black marks a lot and food colored water. Film it with a stationary video camera pointed at the labeled manometers and call out the speed to the camera. The measurement locations will be the engine compartment hi (by air cleaner inlet) and low (by lower front pulley), and by the rear wheels. The wheel air pressures will be at the front part of wheel and rear part of wheel, both sides, 4 measurement points. So, it looks like a baseline is going to be established for what the air is doing back there. This will be an experiment to take guess work out of any bolt-on ground effects device.

The first proposed design is the most basic. A about a foot and a half wide panel that goes from just behind the rear inboard seat mounting bolts, all the way back to the rear frame cross member where the anti-roll bar is attached. Then measurements with the manometers, and sample points will be done in a controlled environment (sanctioned event).

The progression of designs may be enlarged to go wider. I'm thinking no wider than the rear tires, so if it ever flew off, it would pass under the car without cutting the tires. Then some improvements can be made, as an overall progression of underbody downforce theory is applied, tested and measured. The theories, I'll repeat are twofold. First the 'inverted airflow' airlpane wing theory. Second the laboratory water faucet vacuum device theory.

So, refinements in design, and R&D, say that making the underbody channel that encases the
water tubes, is a natural vacuum generator. It can be made more efficient if it is sealed off in a cupped kind of way, like if the car was flipped upside down, it would hold the maximum water without spilling, all the way around. So, seal up the front and rear, or make two vacuum volumes, to see what works best. All around the underside, it's make it smooth, and continuous front to rear and make vauum cups where feasible. The same theorys can be made into options regarding the back side of the radiator. It can be exhausted out the top of the front hood or made into a vacuum chamber like the water tube tunnel. Some of these applications of design may not be so easy to make and install and may not have the greatest impact in performance enhancement, but it's just experimenting to see what works best. Learning is fun, right?

Testing is fun, too. Testing will be done in a stepwise fashion, too. The first constant is ground clearance. No problem. It's about 3" or so off the ground now. So the amplification of ground effect will be not much. I expect modest changes in readings at freeway speeds. Readings will be amplified twofold, increasing to higher speeds and lowering of the chassis both increase downforce. Later experiments for later days. Speed variable at first, ground clearance variable later.

I think it may cost some money to have everything installed by a body shop, welder, machinist, or mechanic, but it's a coming technology, and I think all motor companies are taking a look at it currently, as are all racing enthusiasts all over the world. So, maybe things change for the better.

Take note, I assume no responsibility for anyone else's actions but my own. The same goes for anyone else trying this stuff. Done right, it's going to be an advancement in performance, control, safety and thrill. Done wrong, can lead to irreversible consequences... Do it right, or wait for the technology to be developed and offered, that's what I think is good advice. There, I think I've protected myself from something obvious, but it's putting everyone on notice, and now we can proceed a little further with the fun factor. We'll wait and see what happens next.... For only a little while.

As always, visiting Professors are welcome, and questions from the class are permitted. It's everyone's duty to see that the instructor doesn't do something foolish,

I think some of our Swedish friends looked at air flow over and around the body a couple of years ago. They taped yarn to the body and followed in another car with a camera or video recorder. IIRC, they found a layer of turbulence that extends a couple of inches from the body and a coupleof feet behind the lower back panel.

It doesn't surprise me anymore why that part of the world always produces talented and successful Formula One drivers. If they are like Goram Malmberg, then they are into it big time. A consuming passion.... Application of science, engineering, R&D, creative thought, crative experimentation, and tireless effort. That really inspires me!

Is this method of experimentation and explanation of theory making any sense to you?

I was in a glider years ago, and they had yarn taped to the bubble canopy. It really only showed cross winds during take-off. Once airborne, the yarn was always straight back. Gliders have been perfected for many decades now, like sixty years or more.

However, your recollections suggest a 21st century experiment: fix a video camera, or one of those cheap survellance cameras under the body, in various locations, and tape-record it to a portable VCR, or hand held camera with an auxiliary video input. I'll bet there's turbulance that can be reduced, and demonstrated too, by video. Less tuirbulance, less lift. More sleek windage, more downforce.

I wonder if you are thinking of providing some data points with the manometers. I had to rethink the manometers and now think it's better to leave both ends unplugged. This will allow for more accurate readings of positive (+) air pressure and negative (vacuum) (-) air pressure. I think the tubes need to be about 12"" to 18" tall, vertical length, to allow for the water to climb either side.

Then the idea is to drill holes in the experimental devices at the same data sample points as the baseline sample points and demonstrate the downforce generated with the manometer measurements. It would be a throw away experimental device, just to prove the effectiveness of the applied theory underbody panel. I see improvements in downforce generation with short lips running the length of the undebody panel, on the outsides, like maybe 0.5".

My theory why race cars' rear diffusers work is it creates dual or triple spinning vortexes of air, that are lower to the ground, and create less negative (vacuum) air pressure, which is invisible drag. We are aware of this effect by exhaust deposits on the back of our white bodied Pantera's aren't we, Jim? I am not envisioning any rear diffusers at this point in time, just effective underbody panels to decrease the air pressure in the engine area and to create downforce on the underside of the underbody panel.

I suspect that even with maximmum lowering of the vehicle and 150 mph, the order of magnitude of downforce generated will be under 500 pounds. This would be ideal. It would allow for less fatigue of the underbody panel aluminum.

I also envision using the seat bolts as the front anchor points, and I'll use hardened bolts with a hole drilled for a cotter pin, and those slotted nuts. Then a couple of points on each side of the frame, inside the engine bay, with similar locking nuts and drilled bolts. I think there will still be sufficient air passage into the engine bay, but at lower pressure. I think there will still be sufficient cooling of the headers too. I also see the desired color for the underbody panel as black, to avoid too many questions from admiring viewers of the vehicle in parking lots and gas stations. I think the final version will have 'wings' probably. They will extend outboard from the rear frame section by about 3 to 4" on each side, and back from the gas tank about 1 to 2" and the same on the other side of the vehicle, at the leading edge of the rear wheel.

Off topic happy note:
Taxes done, just need to copy onto the nice clean forms to get rid of all the black pen scratch out marks. Nice clean final draft. I'm happy to get it done, for sure.

quote:

(sanctioned event).

If the measurement is to work it would have to be straight line and relatively smooth so as not to agitate the liquid.

Good point. And the interior windows rolled up so as not to create drafts on the open ends of the manometer tubes. We just want order-of-magnitude baseline measurments to see if any experimental devices actually work. They have to have measurable downforce generated, or the project is a failure, and the experiments should be object, void of opinion.

Everyone is invited to participate and submit test results of their manometer readings, sample point locations, etc. This is statistical data that won't lie or brag. I expect some variations of observed sample data among similar body style Panteras, and maybe more variations between L/Pre-L, GT-5, and GT-5S Pantera's.

My Pantera is on jack stands with the half shafts removed at the moment. I expect all the parts to arrive for my updated 4 piston brake caliper, directional ventilated, cross drilled, slotted rotors project to arrive no later than next week, so any testing will have to wait for a while.

Gee, I hope I don't get stopped for a burned out tail light or something and have to answer a bunch of questions about why a dozen 1/4" O.D. tubes are running into my cockpit from all over the car.... That may take hours to explain.

I think I'll just tell the Officer I'm seperating Argon out of the atmospheric gasses and I am trying to distill a little rarefied, noble gasses too. Want some purified atmospheric argon or neon Officer? Just place your lips right here and take a deep breath....

I'm sure at least one of you won't appreciate that joke, so I'll apologize in advance. My profession is the butt of many jokes, and I just take it in stride anyway.

I'm thinking 1/4" thick aluminum plate is sturdy enough for most applications of experimental ground effects underbody panels.

Another location to affix it to is a bolt on each side of the motor mounts, then, as stated, at least one each from the inboard rear seat mounting bolt under the chassis, then a couple of horse shoe straps over the rear frame sections on each side in the engine compartment.

I hope some measurable results are obtained, or we just waste lots of time and only a little bit of money. Thomas Edison, America's most prolific inventor, made over 1,000 experiments before perfecting the light bulb. Turned out to be a tungsten filament in a vacuum, with an atmosphere purged of oxygen that did the trick.

Fascinating to me. Gee, I want to be more like him!

Ground Effects??? Aerodynamics??? Why???


http://www.openwheelers.com.au/videos/Top_Gear_Ariel_Atom_2_Full_segment
.mpg


http://www.arielmotor.co.uk/04/frames.htm

Body Design

The S7’s beautiful shape was “designed” by the wind. Optimal aerodynamics and top speed performance objectives were achieved with extensive wind tunnel work. Targets included a low coefficient of drag, optimum drag-to-lift ratio, and extreme down force. The S7 has “full tray” body sculpting underneath.

http://www.exoticcarsite.com/pages/saleen_s7_2004.htm

At 2,750 pounds, Saleen states their S7 will create enough downforce at 160 mph to be able to drive upside down. So it must generate at least 2,751 pounds of downforce at 160 mph. How would you like to take a corner in that car? A little quicker around the apex than you're comfortable doing in the everyday driver, for a quickie thrill.

I want a little more performance than my Pantera currently provides, and I think it can be done relatively inexpensively, certainly less than $375,000. Even without carbon fiber.

But, if I won the lottery....

Here's a hint of what Saleen's S7 underbody tray looks like:
http://www.rsportscars.com/foto/07/saleens705_engine.jpg
http://www.rsportscars.com/foto/07/saleens705_engine2.jpg

OK, so now everybody has a pretty good idea of what I am going to doing with my Pantera over the next 12 months, and probably can visualize the end result with close approximation to the end result. I want to thank all the contributors to this topic. The information you guys supplemented this ground effects topic with have helped me formulate a better plan. Now, I'm going to get back to the brake upgrade project and be ready for Vegas 2005. I'll be paying close attention to the next few issues of Pantera Internationals to see what types of air adjustable shocks to use, since Goram Malmberg will be making his presentation in the upcoming issues. If you don't get PI, you should, this is cutting edge stuff. And, on that note, this "on-line research seminar" is concluded. It will take a little R&D, some effort, some metal fabricator vendor contact, and some testing before there's much more for me to talk about. I've pretty much disclosed everything I know about the subject at this point. We'll see you what it looks like and what it does in the near future. Thanks for your interest.

VFI

This week's Guest Professor for our "Ground Effects" Continuing Education On-Line Seminar is:

Peter Matchet

He's making a few more comments on Ground Effects and you can see him right in your ownliving room on Speed Channel doing the commentary for F-1 Decade, a program that cover's this week's Formula One race ten years ago. The first episode is on tonight, Fri 3/18/05, and he has teriffic insight into this stuff. The program repeats all weekend long, so tune in and test your new knowledge against his.

If you tune into Speed Channel you'll see F-1 qualifying, practice, and the race from Malaysia, along with 100,000,000 other viewers worlwide. You may find the things you see and hear about a little more interesting, after having attended this seminar up to this point.

Only we have a secret. We don't have to have a wind tunnel to measure and test ground effects, do we? We can use little clear hoses filled with colored water and a road test to determine what's happening to the air under, around and in the engine bay of our Pantera's.

VFI,
I've been following your thread here with interest (not that I'll ever approach 200 mph in my cat), but if you get a chance, you might snag a copy of Smokey Yunicks' book "Best Damn Garage In Town". He spent 50+ years around race cars of every type & description from NASCAR to Indy & talks a lot about aerodynamics & ground effects. Very interesting stuff! Just be prepared for a lot of reading (600+ pages). I received a copy for Christmas & am still working on getting it all read!

Bob Radefeld #5042

Hi Bob,
I bought your polished Edelbrock Performer intake from you July 2003. We talked a little and you said if I ever get a chance to track the Pantera, I should do it. You drove your Pantera down to do the track with the Space City Pantera guys. I'm doing what you said, just like you did. Drive it there, race it around, drive it back. About the same driving distance for me as you did that time.

If you know where I (or we) can get this book, please post a link. I have lots of Pantera books, and like to keep a library of good stuff. Mostly, I use the index and table of contents to get the chapters I like for the moment and don't go cover to cover, page by page for such research materials. Thanks for this tip.

Actually, the F-1 Decade program was not as enlightening as the Round One Qualifying, Formula One, Malaysia. There's more close ups of the cars in the qualifying, to get a good look at the ground effects. I noticed how the main ground effects are at the rear of the car, where the greatest mass (weight) is. Also heard a comment about putting the lower rear winglets about an inch and a half distance from the front edge of the tire, so if the tire deflates, and wobbles on the rim, it doesn't get cut by the rear trailing edge of the wing.

I also noticed that the lowest point of ground clearance is at the leading edge of the barge board. That's the aerodynamic device positioned about under the F-1 driver's knees. I think it is rules changes that prevents the front wing from spanning all the way across in front. Anyway, there's always some understeer, so more effort is made to adjust that front wing all the time.

I found myself crawling under my Pantera immediately after the F-1 programs to view instalation of a Pantera front ground effects device. I have the little GTS 'chin spoiler' and can see that it will be easy to put a plate of aluminum from under that and make connecting devices thru the oval holes in the front valance. (Don't want to be drilling holes everywhere, must be able to convert back to stock.) Make some similar ovals of steel, tap and thread holes, and twist 90 degrees after fitting thru lower valance holes. The front under tray shall extend rearward to the back-bottom of the radiator. Then I see the water tube tunnel is in need of a flat vertical section of aluminun to create a vacuum chamber, at the part where the water tubes fit to the hoses going to the radiator.

I was looking at those front barge boards thinking, these guys have that thing extending forward to scoop up air and deflect it to the sides, lowering air pressure from flowing underneath. Then I thought, that would be a possibility to do something similar on the Pantera, to divert the air away from the center and to the flat sides, would lower the air pressure in the water tube tunnel, and speed it up on the flat undersides. That may work, when I bottom out on speed bumps, it's the area under the seats. So, if something was lower than that, and it was very close to the front wheels, then it sill wouldn't bottom out.

I may go 200 mph, once in my lifetime, at an open highway, sanctioned event. It will take some time. I will need a taller fifth gear, and maybe one tooth higher final drive gear, along with a few more rpm's and horsepower. There's no hurry to do it all today or anything though.

The purpose is simply to have a dual purpose Pantera. Street and track. For flat/smooth tracks, the car can be lowered for maximum downforce, leading to better cornering G-loading and more grip for braking, and more stability at top speed on the straights. Then for the street, it's back up to normal ground clearance, and somewhat diminished downforce, but still better stability at freeway speed and better grip for braking from higher freeway speeds, like for an emergency r if a deer jumps in front of me, I can really stop fast on the freeway. (That deer thing happened to me once outsdie Flagstaff, AZ, seemed like it was just inches as that deer went boink, boink, boink, and crossed from one side of the forest to the other, 30 yards in three boinks.)

A little creative metal bending and a few hundred bucks for a little experiment. Starting out with paper patterns using grocery sacks, then cardboard mockups, then some thin aluminum to get a mock-up fitted, then some heavier gauge aluminum plating that I can have fabricated with all the tabs and holes and bends defined clearly by the thin gauge mock up for the fabricator. And maybe 500 to 800 more pounds of downforce at 160 mph. A nice solid, heavy feel to the steering wheel at 160 mph, and knowingI can cut 20% off the braking distance at that speed is the goal. These Pantera's go that fast, from the factory, so maybe some inexpensive ground effects make them a little safer at those speeds....

I just think it's fun.

Ron Norman
#THPNNJ05201

Hey Ron,
Didn't realize that VFI was you!! Great to hear from you again. Hope the manifold turned out to be ok for you. Remember I was going to change to an X-celerator single plane when I was rebuilding my engine? It and the other goodies I put in really gave my Kitty some claws- have been more than happy with the results (kudos to Dan Jones in St. Louis for helping me pick the right parts!!). BTW, wifey ordered the Smokey Yunick book through our local Barnes & Noble book store & it took them 4-5 weeks to get it in - almost missed being here for Christmas. It's a hell of a book & if you ever get a chance to read it you won't be disappointed I guarantee! While reading it you'll be amazed at everything Smokey was involved in and you'll definitely question as I do, how this guy ever lived as long as he did! I think he just died last year, but reading the book you'll wonder how he ever managed to live past 21. Take Care & keep in touch!

Bob

Hi Bob, hey can I ask a question of you? I'm thinking of putting a centrifugal supercharger on my 351-C. Hang it right on the A/C bracket and plub up the intake to the carb. There's a kit in JEG's for 1964-1968 superchargers, for carb'd 289's and 302's. I'd like to strap on 50% more h.p. and think this may be a cool way to go. This cat will probably get another engine before it goes from 43K miles to 100,000 miles anyways, so high mileage reliability isn't a concern. I have the original low compression 351-C with advanced timing, and that's about it, other than an Edelbrock 600 and your manifold. I'd like to still get good gas mileage, and a fairly drivable cat, with the ability to nail-it and feel the G-force in my neck really hard, so about 450 to 500 h.p. with 'reliability' being a function of not running it 100% more than occassionally. It seems like always there will be all these things competing for my Pantera dollars always. So I like to stretch out the dollars like everybody else. Can you inquire with your engine guru in St. Louis, if you talk occassionally? And, if it's not top secret, can you tell all of who are interested, what you did to your engine? It may be wise for us to start a new topic in this Technical Advice and Questions Forum. We can just link it up in this thread, so there's a new topic and a continuing topic, if you're agreeable? Thanks, I have to know how the claws on your kitty got there. Are you measuring the h.p. with the Racepak Data or G-Force Meters?

Ron,
There is a gentleman by the name of Dick Koch in Atlanta that has dual superchargers on his cat. He posts quite often on the Detomaso Forum as does Dan Jones. I haven't personally had the pleasure of speaking to Dan as all of his assistance on my engine was done via e-mail. He's currently building a killer engine for his cat & is a very busy guy so is often hard to get ahold of. No secrets to my engine - original block bored .030, forged flat top pistons, 2V quench heads w/stainless steel single piece valves, custom ground cam by "Rocket"cam company (spec'ed by Dan),Roller rockers,X-celerator single plane manifold, & 650 Speed Demon carb topped off with a chrome 14" air cleaner w/ K&N air filter. Don't have a Dyno in Topeka, so don't have any real HP figures, but my "Butt-O-Meter" tells me I've got lots more power & torque than with the old low compression engine I started out with. Hopefully, one day I'll get her on a dyno & I'll get some real #'s.

Bob

Thanks for the tips, Bob. I'll be meeting Dick Koch in a few weeks. He and some other Pantera enthusiasts are going to come by my house Tuesday night, April 26 and we'll caravan out to Vegas for the track event the following day, so I'll have the pleasure of being able to see his setup and maybe he'll field a few questions from me. Jack DeRyke wrote a post in this forum a couple of years ago about his 351-C mods and they sound a lot like your engine. It's an upgrade planned in a year or two, for me. So it's just at the study phase, sort of like this ground effects topic.

Back to the ground effects topic. I got PI Motorsports 2004-05 Catalog today, and it's 160 pages. Notably, page 158 has the graphs of the wind tunnel tests done on the original Pantera and the original GT-40. Page 159 has photographs of the monocoque body/frame. Those are the intesting pieces of information I'm going to comment on in a second. Right now, I have to say that Jerry and Dave and Linda have done a lot of work compiling this catalog. There's exploded diagrams of everything. That's valuable to me for when I need to tackle a project, I can see ahead of time how it was assembled at the engineering designer's drawing board. It's truly inspirational to see all this Pantera stuff, and to me, quite humbling. These guys are extreme Pantera enthusiasts, and I'm a babe in the woods on the information-Pantera aspect of life.

First, the wind tunnel results, page 158. At 160 mph, the 'stock body' Pantera produces about 290 pounds of lift in the front and 120 pounds of lift in the rear. The GT-40 produced 260 pounds of lift in front and -40 pounds of lift in the rear. So, the GT-40 produced 40 pounds of downforce in the rear, or generated 40 pounds of ground effects. At 160 mph (260 kph), the Pantera produces 554 pounds (252 Kg) of drag and the GT-40 produced 477 pounds (217 Kg) of drag.

Drag is visualized by the seeing a box pushing against 160 mph of air, vs. a ball of the same size pushing against 160 mph of air. It has nothing to do with lift of lift's inverse: downforce. Drag is resistance to movement and the Pantera consumes 238 hp just to compensate for the aerodynamic drag. The GT-40 requires 217 hp to balance the air resistance of 160 mph wind. So, the efficiency of the two body styles are similar in terms of drag. F-1 cars have pointy noses, and similar features, creating less drag, and so require less hp to go 160 mph. What all this means is drag is something takes hp to overcome. More protrusions, like scoops, create more drag, so will accelerate less quickly from 160 mph to 200 mph with the same hp. I don't see any cost effective way to reduce drag. It's what it is already with the existing body style.

Lift is a bad thing, downforce a good thing. There's 1,365 pounds of weight on the front wheels of the Pantera standing still. Subtract 290 pounds for lift at 160 mph, and the tire contact patch gets smaller because the 'weight' on the front wheels is only 1,075 pounds. At 120 mph, lift is 160 pounds on the front. Simple extrapolations tells us at 200 mph, 290-160=130, so 130+290=420 pounds of lift at 200 mph. So, the tire contact patch (control of vehicle) is lessened as the apparent weight of the Pantera is 1,365 pounds on the front minus 420 is 945 pounds on the front tires.

I won't bore you with so many details.

Summarizing, I did a similar extrapolation to 200 mph for drag using the graphs, and it would take 376 hp to compensate for aerodynamic drag at 200 mph. Same extrapolation for the lift at the rear: At 200 mph, 160 pounds of lift occurs at the rear wheels of the Pantera.

Conclusions:
The drag problem is not easily improved, but can be made worse, and it is a compromise issue. For example, if there's a large front spoiler which is 1/4" off the pavement in front, it will create more drag, but will reduce the front and rear lift. This is because the air speed (wind) creates lift, reduce the ability of the air to get under the Pantera, and it will improve the 'downforce' or at least reduce 'lift'. True downforce will be generated by near absence of wind, or air speed, under the Pantera, just like the Saleen S-7.

Another conclusion:
The front of the Pantera is where the most effort needs to be focused, because that's where the greatest lift is happening. The front is also where the drag is happening. True, there's some drag happening at the rear of the Pantera, where the exhaust fumes get sucked back and plated onto the rear bumpers and bodywork, but it's the front that needs the most attention.

Final conclusion:
Like the Saleen S-7 seems like it would be severly compromised going over a speed bump, it is more focused on going very fast on a very smooth track. And the opposite also, I can clear speed bumps fine, but my Pantera doesn't seems like it would be stable at 200 mph, as is. It would need to be lowered to reduce the amount of windage underneath and it would need an underbody tray that sort of copycat's the S-7's underbody tray.

Last, and the final final conclusion (for now):
The main difference visually comparing the Pantera and GT-40 is how the air is channeled through the radiator. The stock Pantera has the air exhausting out the back of the radiator and underneath the car. The GT-40 has the radiator exhaust air exiting out th top, over the hood of the car. This may account for their differences in drag: 252-231=21Kg x2.2=46 pounds less drag in the GT-40 at 160 mph and front lift: 35 popunds less in the GT-40. The pictures of the monocoque frame/body seem to be suggesting to me that there's probably only one economical way to make these lift/drag problems better. Lower the Pantera and install a full body under-tray, meaning the radiator would have to exhaust out the hood vents.

The truth is: If I want to friggin' go 200 mph, I should just go rent one of these supercars, and pay up that way, it'll cost much less that way. Maybe there's just no way to have it all, a car to go around town in without scraping every bump in the road and take 200 mph at the track. I think I'll just hang out with you guys and let the Lamborghini and Ferrari guys talk about 200 mph without actually doing it, them or me. I give up on this for now, but would like any feedback, so I'll hand over the microphone to the next speaker here....

See you guys in Vegas...