Fast sportscars.

I am a 65 years old "former" guitar builder. In fact I still do build guitars now and then for special customers. PA speaker system and bass exponential horn construction was also a big part of my work. Right now I am also working on my second book about chassis engineering. So the car is sort of a testing bench as I find "real world experience" mandatory to be able to write with my own words. I am also an old rock band bass player at the 60-70: s. As for sports, ski jumping, was my favourite at young age. In later years slalom was the things until my right knee get broken. In the 80: s I did a lot weight lifting and bodybuilding where power lifting was my best discipline. Model jet airplane racing is another favourite, using pulsjet engine. And of corse, sportscar driving is top of the line.

The faster the better. There are very few fast factory cars to buy on the market. In fact, most "sportscars" are regular cars with another look. Those cars are OK for a city night cruises, but I am more interested in no compromise driving machines. Real fast sports cars, starts off at $400000. Like Mac Laren or Ferrari F-40. A little to much for me. So, there is but one thing left to me . To take a suitable "sportscar", rebuild and modify the chassis and supply it with a powerful engine. I am not harbouring the idea of creating the ultimate sports car. But I don't mind trying . There are no such beast as the "ultimate" or, "the best" sports car anyway. Any car can only be made to suite a specific purpose. Anything too much or less, to serve that purpose, is an engineering failure. As Colin Chapman once stated, the car should fall in apart when passing the finish line. If it does earlier, it's to weak. And if it does after the finish line, it is to heavily built.

A short history. I bought my first Pantera 31 years ago. Over the years this car has had 5 different engines; Ex a nascar 302 Ford by Falconeer, a 500 cui 385 Ford etc. I have also used a number of different suspension parts and brakes. During the gulf war business went bad, so I had to sell the car. When the sun started to climb again it was time to build oneself a new Pantera.( But Of Course, it had to be a Pantera!!) but what powerplant could fill the bill? I had already used almost every Ford motor (save a SOCH ) and starved for something different. Today, Chrysler makes the V-10 Viper. A fairly fast car. But, in case you did not know, 35 years ago Chrysler produced an engine beyond comparsion. Making the cars it powered as fast, or even faster, than the Viper, (however , though , not around corners).

The present car. Pantera GT-5, totally restored. Crowned with the muscle engine of all times, the 426 HEMI. Stroked to 526cui. The GT-5 was released in 1980. Basically the same old Pantera but sporting a wing, fenders and skirts. Plus the old group-4 wheels 10x15 and 13x15. Heavier bars-shocks-spring combinations and larger bearing rear upprights. However, my car is a 1973 GTS, having been converted with the factory GT-5 set up. 1999 I had the car legally registrated including tire dimensions, roll cage, GT-5 set up and last but not least, the HEMI engine with injection

The Pantera.

Why a Pantera? As well as for the engine, I dont care very much for what make the car is, but the Pantera do have a few things going for it. It is a nice looking car. Technically it has an all steel monocoque. It is said to be torsionally weak, but this is mostly due to rust and age. It provides a roomy engine bay accepting almost any engine. Maybe not the V-10 engin, as length is one of the engine bays few limitations. Suspension is the same as on most racing cars, so handling is very much a question of setting the car up properly. (Please see the section on A-arms). In all, it is very much within the possibilities of a private garage. Creatures such as the F-40 has better adjustability for suspension geometry, bars etc. Pantera is missing much of this. If adjusting the sway bar, one finds oneself forced to change to another rate bar. On the other hand it has a very reliable and clean and neat installation. I do like simplicity. The car should have NO more parts than absolutely necessary. I this context, the Pantera is well suited as a street car. Surprisingly , perhaps , many items that makes race cars fast actually makes a streetcar slower. (Se spring settings)

The Engine.

Why a Hemi? It is a legendary engine. In fact, it is the world's fastest engine. It holds the top fuel record with 4,47 sec and 534km/hr. It holds the ss/aa (stock) 1/4 mile record with a Hemi Baracuda at 8,64 sec in the . In prostock it holds the trap speed record at 327 km/hr. And last but not least, salt flat piston-engine wheel-driven car speed record, of 432 mph or 692km/hr. The Hemi is like having some racing history in the car.

Motor-horsepower philosophy. Some of you may wonder about this elephant motor in a sports car. Sports cars are supposed have small 15000-rpm motors. Well, I am of a somewhat different opinion . The only number of interest is horsepower . Horsepower is related to how much air and fuel the engine can burn, per time. Which in turn is related to how many cubic inches of swept volume the piston produce, per time. Presumed we are talking about engines with an efficiency of near 100%, cubic inches is about the only way to more power, since rpm is limited. More cubic inches per time can be had by.....

1) Larger piston area.

2) Higher piston speed. Which in turn is related to...... A) More rpm....... B) More stroke.

3) Supercharging or Nos. This is not the area of subject here.

Racing cars has limitations for engine size. Therfore, they use rpm, to produce more cubic inches, per time. On the street we do not suffer racing regulations.. And as this is a pushrod engine, I therefore limited the rpm to a rather relaxed 7000 for the street. I ´d rather use stroke to create mass flow. Some sports car gurus claim a long stroke big incher will suffer from dull throttle response. In my opinion this is not necessaraly true, as pistons acceleration at its mean piston speed (mps), has got nothing or little to do with stroke.
However, an over-square engine do not have the same head area to give room for biggest possible valve area in relation to cui. But the Hemi can take a lot stroke without running in to that sort of problems.

What about torque??? Torque is a good indication of efficiency , mcp , mean combustion pressure . How well the combination of induction, head porting, combustion chamber, exhaust headers, camshaft and engine geometry, all work together. Here is (my own) rule of the thumb. 0,1Nm per cc engine size represent close to 100% volumetric efficiency. In my case (526 cui = 8626 cm2), x 0,1 Nm = 862 Nm = 633 foot-pound. So, to be accepted as an OK engine build up, my engine has to be able to deliver 633 foot-pound of torque.

This Ferrari F-50 GT deliver 520 Nm from 4700 cc. 520/4700 = 0,11. Which equals 0,10% boast without a charger.

Torque, is commonly misconstrued as power at low rpm. Please let go of this misconception! It is not. To move a car faster, at low (as well as high) rpm, the engine must produce more horsepower. If a 3000-pound car should do the quarter in 10 seconds , we have to have 600 horsepower at the rear wheels. It is mathematically impossible to tell how many foot-pounds of torque that is needed to do the work. Of course, we can say, xxx fp of torque at yyy rpm , but then we are talking horsepower again. ( hp = torque x rpm ) , hence, high rpm torque produces the best HP. In other words, I like my motor to produce torque at high rpm. In fact, the best torque producers are very high rpm motors. Those take real advantage of tuned intake and exhaust system, ported heads etc. So, when it comes to specify a quantity of work, the correct way of referring to it is horsepower. Even at low rpm.......

A drawback with a big incher is that the engine get physically big and heavy. By the use of aluminium heads etc, my car weights in at 2600 pounds, this is lighter than the original Pantera with a 351 Cleveland stopping the scale at 3100-3200 pounds.

Engine. The old HEMI is conducted by a modern engine management system by Haltech E6-K. The motor is based on the new cast iron HEMI block. At first I used a aluminium block, but this was of a fueler steel liner type that did not work well for a gasoline engine. At a cost of 60 pound I selected the more reliable iron block. After all, the block sits very low in the chassis and may also help acceleration a bit due to its closeness to the rear wheels. 7-inch billet alu rods and piston with "ring land" pin. Even with this long rod the ratio is only 1,59:1. Alu rods have reputation not to last very long. According to the manufacturer the rods will live for 40000 miles. My engine is apart every 4000 miles. And by 40000 miles, every vital part has been replaced anyway. A 4,40 stroke billet crank necessitates grinding out the block and remove the original provision for oil pickup. But as I use the KB pump, oil pickup hoses runs outside the engine.

Hemi heads. The heads is what separates a Hemi from other engines. It has been a lot discussion about Hemi vs the wedge design combustion chamber. As with everything, there is no optimum chamber design. It all depends on what we want the engine to do. Hemis have a 170 cc combustion chamber, great for top fuelers but not for a gasoline 426 engine, as we end up with 6,5:1 cr ratio with a flat top piston. Or, one must use a big dome that creates an orange-shell-shape combustion chamber with deep valve notches, shrouding the valves . But with the additional 100, or better still 200 inches, we can make the Hemi head shine. With a small circular quench-dome we have a street able 10,5:1 cr ratio, and a nice burning chamber. With a 15:1 cr pro stock racing engine, limited to 500 cui, we are back in to troubble again. This is the reason the new prostock Hemi use quench areas in the heads.

The installation, of the Hemi in the Pantera required a few things to be fabricated. An adapter plate to fit the gearbox bell housing to the engine. Header fabrication, and a 3-inch exhaust system. Reworking of a Ford aluminium flywheel to suite the Hemi crankshaft. Machine the Hemiblock to allow for a right hand side starter motor. Adapters to suit Pantera motor mount. Machine the heads for water outlets. Plugging of the block water outlet and machine the block for a short style Chevy water pump. Fabrication of a new oil pan. These are the main items , then it is just some belt pulleys, alternator brackets etc, like always in a build up.

Oil pan. Is a story for itself in a wet and this very close to ground installation? This is my 4;Th pan. And now it seems to function properly. Of course, I could have used a dry system, as in my earlier Panteras, but the KB pump made a clean installation without to much hoses belts etc. And a stimulating challenges to make a wet pan to carry over 1g in any direction. A good design oil pan is important since it allows the use of smaller quantities of oil, without the risk of oil starvation. I want the engine to warm up quickly, which is not possible if too much oil is used. This pan is designed to hold 6 quart of oil, which is enough to prevent from any possibility to suck air. However, if I happen to be in a situation of a long distance driving, where there is a risk of the engine consuming oil, the pan can handle an extra 2-quarter. And the pan is safe down to 4 quart.

 

My first version of the engine build-up. Aluminium block was used and a carb for induction. Unilite and MSD ignition. In a mid engine configuration we do not want the engine to protrude in to the coupe of the car. To make the engine short I use a short Chevy water pump. Water outlet is then routed from the heads. Starter is relocated to the right side in order to suit the bell house of the ZF gearbox. For the same reason a Ford aluminium flywheel is fitted to the crank	Cranktrigger. This is what you see when the cower is removed between the seats. In front of the ATI damper is the belt pulley and trigger wheel. All tightly together for shortest possible length. A short belt and deep groovie pulleys also keeps the belt from leaving it`s place at 7000 rpm. A plate that holds a thrust roller bearing for the camshaft replaces the original front of the gear drive.	After 600 miles the pcv system has drown 1/2 a pint of oil and water out of the motor! The wite part at the bottom is a high water to oil blend. The water comes from condens created by the motor acting as an air pump. The catch can is mounted higher than the valvcover.

Engine adapter plate	Rocker stands	Oil pan	Oil scraper

This drawing show my former drysump system design. Pump is very low mounted on a oilpan bracket. A number of scrapers over the full lenght of the crankchaft.

Engine spec.

Engine is now configured for alcohol use, E 85. However, the compression ratio is still 10,5:1 which is to low.

Block is late cast iron Hemi . Crank 4,40 stroke billet . Rods 7-inch billet aluminium, ratio1,59:1. Piston 10,5:1 Cr. Heads aluminium, ported by KB. Aluminium rocker chaft mounts. Valve spring 200 pound seat pressure. Retainers titanium. Camshaft 264 degree@ ,050 roller. Gear cam-drive. Intake, Rebuilt Weiand tunnel-ram manifold. KB oil pump. ATI hm damper. Oil pan, 8 quart wet sump. Exhaust headers 4 to1. Crank trigger 4 magnets.

The injection, ignition.

As I have no dyno , I did all the injection programming, driving on the road . To make injection timing a little more visible, I transferred the numbers to excel format , to be able to look at everything in 3-d form. I also used a lambda sond for analysis. After some 30 years of all types of carburettor tuning, it is quite interesting to see a hard copy of all injection numbers. Some were very surprising. Especially the Webers have given me a rather solid background from which to view this, and I have developed a feel for how the engine is running. Being musically inclined & a guitar builder is also a great help , as I know the RPM by the note of the engine. Thus making lap top tuning while driving more easy. Equally important with ECU management is ignition timing , which could be set to any chosen degree over the engines entire rpm band. It even allows the engine to run cooler as the timing could be optimised to give crank energy instead of heat. Seen over the whole season of 3000 miles, the engine has appeared to consume some 15% less fuel compared to the carb seasons. The lowest consumption at steady 60 mph, was 16 mpg. The season average is 14 mpg, compared to 12 on carbs. No city driving is represented in those numbers. The engine runs better in traffic, start ups and idles more reliably in coold weather. As for power output, the engine shows better performance over the entire prm spectrum .

Haltech. Become the choice of ecu. I don't think the choice of brand matters very much, so I just bought what the speed shop had sold a lot of. The first ecu used was the Haltech E6S. Everything seemed fine with it, except the engine refused to rev beyond 5500 rpm. I tried with Msd6AL and the Accel 300+ ignitions. The E6S had problems trigger both of them. It also showed cranking ignition problems. But this was due to triggering of the Haltech with Mallory unilite. It seem to come from high current draw of the starter motor, and the very low cranking speed of the big engine. I tried 3 Mallory modules with the same results. After a sending the whole ignition system to Haltech AU, I was told that the ecu was faulty. I received a new E6K, which is a better unit. This time I triggered the ecu with a Haltech hall-effect sensor and 4 magnet crank wheel. This works OK. This set up show no rpm problems. But I still got triggering problems of the Accel 300+ amp. The Msd works much better, espesially when my 40 ah cooling fan goes on. Summary, the Haltech should trigger from their own "hall" sender, and a crank wheel. A crank trigger also makes the distributor cap-rotor phase, an easy task, as twisting the housing does not affect timing. I also recommend Msd in this application. I programmed the ecu in "batch fire", which means the injectors are fired 4 and 4 instead of all together. Of course, sequential firing would be the optimal, even from a pulsation standpoint. But it takes 8 channels. And there is hardly any performance gain to have. I rather save channels for the ignition later on.

Intake manifold. I used a Weiand tunnel ram, as a base to fabricate an intake manifold. Tunnel rams are well known , not to work very well as a street manifold. But this is more of a carb problem. The big plenum of a tunnel-ram is hard to handle for a carb. In a port fuel injection set up, it turns out pretty great. Here are som reasons...

1, 426 tunnel-ram channel areas is design for high revs. But with 526 cui 3,9 square inch area will put the torque peak down to just over 5000 rpm.

2, The channel is longer than the dual plane which gives better low end.

3, Very straight and thereby easy ported channels.

4, There are no "accelerator pump filling the plenum" problem, since the injectors are close to the heads. For the same reason we do not suffer from weak venturi booster signal, commonly associated with tunnel ram manifolds (using carbs)

If there is anything not so good, it will be the plenum chamber. Todays V-shape "bottom to runner" designs has better runner entry from the plenum. I may come up with something here......

However, a 12-inch long runner will work in between 5500 and 6500 rpm, on the 4th wave. Which only assist the volumetric efficiency by 3-5%. A killer length would be a 15-inch cannel, working on the 4th from 4500 to 5500, and the 3rd vave with a 8% rise of the Ve from 5500 to 6500. The only problem is, how do I make the channel 15 inches long?

Injectors. 8 low impedance "peak and hold" of 100 pound/hr capacity. Enough for 1000 hp. Those injectors works great even at idle, although very short timing. Current draw is 15 ah at higher rpm. A10 ah fuse will go off at about 5000 rpm. Together with a 50 ah fan and a large volume gas pump, a very good alternator is needed to keep injectors (and the whole system) to function properly.

Fuel rails. I fabricated fuel rails from 1x1, 5 inch aluminium bar. Fuel line is 3/4" diameter. Both rails is running in parallel to the pressure regulator and return line, which is good for delivering the same fuel pressure to all injectors.

Trottle body. Is made from a Pro Holley throttle plate. In place of the venturi housing I fabricated a 2" thick 4 hole aluminium billet housing. I estimate the flow to 12-1300 cfm. The housing has a bracket for the throttle position sensor. And accept standard air filter base.

Ignitions. Right now I am using Msd 6AL, and a distributor. Sequential ignitions look interesting, but require 8 coils and the Haltech does not have 8 channels left. The 4 coils "wasted spark semi sequential system" does not appeal to me, and the MSD deliver spark power enough for the rpm used. The full sequential 8-coil system makes a very nice spark plug wire routing. With 4 spark wires coming in from each side of the motor. One also gets rid of the distributor, which is now almost hitting the firewall.

Sparkplug readings

Sparkplug and fuel tuning

Exhaust.

Headers are 31 x 2,11 inches, giving the engine a peak at 6000 rpm. I have my own (guitar tuning) trick of tuning the exhaust primary pipes. By listening to the note of the pipe, it is possible to tune all primary (and secondary pipes respectively) to the same frequency even though this might result , due to bends and such , in some discrepancy in actual physical length. Think of it as an organ pipe. Sing a note in the pipe listening for the resonance to tune in. The frequency is a function of air volume and pipe length. Staggered pipes they may be , but we´ve got the resonance length spot on!. And frequencies is what the engine senses. A fraction of an inch is easily detected in the variance of note. End pipes are 3 inches x 25. To quiet the car I use two 3-inch Supertrapps. They got two great features. Low weight and small size. The downside is (or may be....to some...) that they are rather loud. This is mostly due to way to small a dampening volume for the engine this size. Less than 20 discs and there is too much restriction and results in over heating of the heads. On the track, it is just to remove all discs and ; Voilá , I´ve got myself a great , if short , open system.

Another interesting side effect of "guitartuning" the exhaust is that it provides great music! Especially with the very short system of the Pantera which responds to almost any change in pipe design. And as no surprise, good note and performance are more often than not very , closely related.

180 degree headers, 90-degree headers, tri-Y headers. Well, I use regular headers. In my earlier car I have been using all type of headers. The 180 and even more so the 90 headers give a V-8 the same sound as a 180-degree crankshaft or V-12. They also look impressive. They do have some tuning advantage and a few more horsepower. But, this design almost allways comes out with too long primarys. Making them suitable for lower rpm engines. On the other hand, regular headers will be to short in the aviable Pantera header-space. With the wide Hemi motor 180;s are an almost impossible fit in the Pantera. The Hemi has a special sound to begin with, that are greatley backed up by regular design headers. After a lot pipe tuning I am proud to say that the car has received a lot attention for having a great heavy sound.

My first big block Ford motor for the Pantera, 1985. This is a 385 series 460 stroked to 500 cui. Using Ford motorsport aluminium headds and intake for dominator carb. Dry sump system and electrical water pump. Also, 90 degree header system.

90 degree headers on a 500 Ford big block. I used this motor in the late1980;s. This system was very quite, and nice sounding. The silencer had a 4 inch core diameter	My 302 Boss Trans Am engines built by Falconer Dunn. Fords highest reving engine ever. 9000 rpm in the Ford catalog. Here equipped with 180 degree headers. The end pipes is close together, important for a great sound. This particular engine produced 427 hp. Four IDA Webers and dry sump oiling.	The pipes is welded together from Hooker bends.They are painted black with heat resistent paint.	Top, 3 inches exhaust pipes with room to spare to the A-arms and halfchaft.

Fabrication pictures.

New IR intake manifold.

Trottle blades.   Butterfly fitment is important. This is an aluminium tool for turning the butterfly to oval shape. Butterfly is sandwiched between the two aluminium clamping tool parts with two screws, using the two holes for the butterfly to be mounted to the trottle shaft. This way the butterfly will stop in a totally closed possition and can not turn any futher.They are made from chrome molley steel in order not to bend.Axle are offset in order for the butterfly not to open itself by wacuum.The diameter is quite large, 2,41".

	Air filter is a must. It must not block the rear mirror sight and be very light and filter the air. It must also supply the engine with cool air.The Lexan holds together by a thin aluminium frame makes for a weight of just over a pound.   I will still be using the Weiand tunnelram bottom but without the plenum and put two trottle body in its place.Stacks that is shaped to make a good air entry in to the runners and also making the runner a little longer than the previous design, now 13,38". One trottlebody with 4 stacks weights in at 2,2p. The butterfly mounting face in the tool is cut at an angle, making the butterfly become oval when cut in the turner. The edge of the butterfly then formes a romboid shape that together with the two offseted mounting holes making the butterfly a one way possition item. It therfore has an arrow marked on the top side. In fact they are also bore fitted.
Header fabrications.
I used a wooden dummy frame of the car when Ibuilt the exhaust system.
.

Butterfly mounting	The tunnel ram bottom is ported to match the trottle bores perfectley.	New model Ford starter motor. Wery light, just 7,7 pounds. It is a revers mounted motor vs solinoid so no "fork" lever is needed to engage the starter gear. Solenoid is right behind the gear. It is also a number of holes drilled in the mounting flange so the starter may be rotated to fit the installation.	I have been unfortune with starter motors, the last years I consumed one per season. This time the drive gear, last year the engagement gear and third year the the cap with the spring seen on the image. Looka like the light inerthia of the rotating assembly together with the slightest back fire destroys the starter.
2003. A new clutch is installed. "The old original 11 inch burnt clutch, from not holding up against the torque. I decidet to try a small diameter two disc set up. The new 8" clutch finiched. It uses two diafraghm springs for good clamping force.	The whole package is 4,4 pounds lighter than the old set-up. This ended up a little to light for street driving. But more troubblesome was the brutal engagement . I made the discs from motorcycle disc brake discs.	Dec 2008! A new clutch again. The two disc racing clutch was a bit hard to use on the street. Hope this one will be a bit smother and still able to handle the Tq. A tight fit pressure plate to bellhousing. Only 1/2 mm in the tightest spot. I guess I have to do some grinding.	"Long throw" slave cylinder is a Volvo 140 unit. Very cheap, does only need a sleeve to fit in the original bracket.
A very simple balance machine!	The brown part in front of the flywheel is hanging down in a bearing and can move sideways then.	It works great for bothstatic and dynamic balancing.	This "cut off" distributor cap is used to synchronize the rotor to cap poles at say 25 degree btdc.

This is a special header "nut" and a stud bolt. Almost natural size picture. The nut is put together from standard details, and is very easy to to tighten by the header side.

Favorite car sites.

Rejsa.nu Svensk race site för alla som gillar kurvor. Deltar en del själv i diskussioner .

Speedlab.se Corvette Racing Team, I am designing the race car for the team.

Roadsters.com Great car site where you find racing parts, car clubs etc.

Prestage Car math with et horsepower time g-force calculations. Articles, databas etc.

Pantera International. Pantera car club site.

de Tomaso.nu Svensk de Tomaso site

Guitar sites. (My proffession is guitarbuilder).

Rolf Wikstrom Show 4 of his Malmberg guitars. (klick on gitarrer).

pm-shopen.se Om man nu skall ha en stereo eller gps. då är detta butiken.

Chassises and components.

Theories. The Pantera is a neither a ground- nor wing-effect car. Well, the GT-5 does sport a big cosmetic rear wing. Over the rear hood.... probably creating "wing to hood" down force instead of "wing to ground" down force. There is a common misconception that a good car should have a 50-50 % weight distribution. The thinking behind this is seems to be that the car should have equal loads on all wheels. However, static weight distribution is valid only in the parking lot............ where no tire grip is necessary.

What is important is how the dynamic weight distribution affects the car. This depends on the whole car as a concept. Extra friction is created by the use of a large and soft rubber area. And it is desirable to under all driving conditions keeping the weight distribution as even as possible over this rubber area, (except during acceleration). Under braking and while cornering all four wheels are used. This calls for a low centre of gravity, in order to to minimize weight transfer. Under acceleration only two wheels are used to move the car. Now the entire weight needs to be at the rear wheels. What is good in one situation is easily disastrous in another. So, I work with what I percieve to be a reasonable static centre of gravity . Which in the case of the Pantera (when over 500 hp) is 60-65% rear bias, backed up by the same proportion tire area. This gives me 55% front load under 1g of braking and thereby a good help from the rear tires. At 1g of acceleration I got 70% rear tire load, to secure a good grip. Then using sway bars, springs, shocks and suspension geometry to handle the weight transfer in the best possible way under different driving condition.

The fastest way is a straight line.Any movement up-down-left - right should be avoided.If the road turns, the driver should straighten out the travel line. When the road has bumps , as small part of the car weight as possible, should move up and down. Here the suspension will straighten out the travel line. When the car corners at its limit, there is scanty litle room for hefty driver actions or hard suspension settings. Emerson Fittipaldi once had a driver's school in England. The school car had a horizontal parabolic cup with a tennis ball in it, mounted on the front hood. The idea of the exercise was that the car should be driven around the track gently enough to maintain the ball in the cup. This teaches one that anything to harsh and heavy will make you loose the ball, or what it symbolizes, the grip at higher speeds.

The monocoque chassis, of the Pantera is made of 0,036" steel , and weighs in at just about 500 pounds, which is not very heavy by any stadards. I like this type of construction where every part of the car adds to the structural strength. Nowadays most racing cars use tub-monocoques out of carbon fibre, where even the engine is involved as a structural member . Great stuff and a similar technique. The steel body of the Pantera does not tolerate rust as this completeley obliterates torsionall stability. In a 30 year old car rust is a problem. No two ways about it! I have torsion tested a number of Pantera chassis. Rusted as well as rebuilt. A rebuilt (or new) chassis is stiff enough for hard street use. Rusted are NEVER!. I tested a nice looking chassis that could only hold 700 foot pound/degree!!! On this car almost all of the profiled middle rocker pantel section was rusted out.

Torsional stability. 700 fp rust figures, has given Pantera a bad stiffness reputaion. Especially since the car not seldom looks quite sound from the outside. Thus making it easy to put it down to bad engineering . People then start to bolt on all kinds of stiffening devices in place of fixing the rust. But even a sound Pantera could use a few more foot pounds of stiffness. When twisting the chassis it is easily seen where flex occurs. Stiffening of those areas by triangulation, is not always easily accomplished. One would prefer be able to get in and out the car, have a motor in the engine bay, etc. This very often result in tubes positioned where there is space left. Bent tubes, and tube joints where the tube intersection does not line up. Tube reinforcements also create new stress concentrations and weak points elsewhere.

Chassis stiffening. My idea has been to reinforce the chassis in a monocoqueish manner . As said, the whole chassis support torsional stability. Certain areas support more load than others. These areas are "profiled" by the same 0,036" sheet metal. Often with a diagonal middle wall, in a three wall "tube" like profile. To make a supporting profile made from 0,036" steel strong, one must see to that the metal recieve straight loads. In other words, there should be no waves in the sheet metal when welded in place. Something which takes an experienced chassis tecnichan to do . The Gt-5 skirt. (rocker panel) was originally made in fibreglass, thus only creating a good looks. I made them in steel, integrated in the chassis with a large cross sectional area. These type of actions stiffen the chassis with neglible addition in weight , which is the very idea with a monocoque. I do have a roll cage, but this is strictly for driver protection. However, I have been driving this car for 16 years with racing rubber. And 8 years with the Hemi. And , to date , without any type of flex related problems.

Floor reinforcement and steel rocker panels. All floor profiles is made on the inside of the car to make a flat under-outside.

Stiffening test.

Chassis frame structure. This is a wooden chassis model of the Pantera "frame" structure. I made this to sort out what happens to the chassis under stress. The model is then dressed up with an outer shell, simulating the outer body panels. The model is twisted, and stressed in all kinds of ways. As a structure only and with outer panels, roof and floor in place. Different types of bracing are applied to see where it does some good. There are two areas of concern, 1. The rear section, 2. The coupe. Needless to say, the structure alone is no stronger than a playing card		I have been driving th Pantera with different torsional stifness numbers and with stock setup coilovers there is hard to separate 5000 to 15000 fp/dgr from each other. But with racing tires and 3 Hz springs and matching dampers, tuning becomes more exact. What really loads the the chassis is the dampers, so schock settings is what is the moost noticeable.

Diagonal engine bay lower part.+0,04 ", 1mm.	Diagonal engine bay. -0,125", 3,2mm.	-0,14", 3,7mm.	+0,011", 0,3mm	+0,0197", 0,5mm. To frame.

Engine bay horisontal. 0,00 "	Rocker panel to roof-window pillar. -0,01" 0,25mm	Coupe diagonal. 0,018", 0,46mm.	Right door+0,02" 0,5mm Left door -0,02", 0,5mm

Hemipanter has a torsional stiffness of 15500 fp/degree.

As for references. Lamborghini Countach 1900 fp/degree. Ferrari 360 spider 6250 fp/degree. Viper gts has a "tube space frame" and 9000 fp/degree. Viper gts-R (Le Mans 24 hr) is reinforced to 13600 fp/degree. Lamborghini Murcielago also uses a high strength tube frame supported with honeycomb carbon fibre to 15000 fp/degree. It clearly shows that the Ferrari has no roof. Here we have cars with cromolly tube frames, carbon fibre, etc. Exotic material, loudly advertised as great stuff that makes those sport scars outstanding. Let me mention that the new SAAB 9-3 Sport Sedan, steel monocoque has a torsional stability of 16000 fp/degree. Showing that good engineering is more important than the use of fancy materials. Embarrassing for the SUPER cars? The Panoz racing car tub carbonfibre monocoque has a stiffness of 45000 fp /degree, but due to the front motor installation the axle to axle ratio is 30000 fp/d, at a weight of 110 pound. A street car that uses a tub monocoque is Koenigsegg . Also made of carbon fibre. This tub is said to have strength of 20500 fp/degree. As this, like the Panoz, is a tub number, the axle to axle ratio should be less. With the same reduction as the Panoz, we should land at 13600 fp/degree. This show that a monocoque is the way to go, even if made in sheet metal. The reason for using steel tube frames is the ease of production in a small numbers. A steel monocoque takes a tremendous investment in tools and engineering.

Aerodynamic.

Wing.

A car wing works in the same manner as an aircraft wing, but upside down. The lifting "vacuum side" of the wing is now the underside. The wing works the best when close to the road and in an undisturbed air stream. Like the front wing of a formula 1 car, that create a high vacuum against the road. The Pantera rear wing is mounted over the rear hood. Creating vacuum between wing and the rear hood is of no use. It is like lifting oneself in the hair.

The look of a wing is spectacular. Widley discussed as beeing a design only item. Aerodynamic is a question beyond personal opinion. A wing could be used to create downforce. No matter what people think of its design. If it makes the car brake and turn better, I will use it. And if the function is OK, I will put some effort to make it look good.

On a ground effect car one might use a wing close to the rear body of the car, to make it work in conjunction with the underside of the car. The Pantera has no rear under side. Instead of creating down force, the car "vacum cleans" the road. Making it nesseary to clean up the engine compartment after every ride.

For a rear wing the only free air stream is quite high . It should also be mounted way back. Wing-(s) should also be positioned so that the centre of down force is located aft of the centre of weight gravity. This self stablices the car at high speed in the same manner as an arrow with feathers in the rear.

The wing could and must be made light because it is the highest point of the car. And has a great lever, like a trailer at the back of the car. And it is possible to make it light beacuse the loads carried by the wing is newer very high. At the most 0,8 pound/square inch. Most likely around 0,5. Down force changes by the square of the speed. If you can push the car by the wing it is probably strong enough.

Does the car need wings?Or better put, aerodynamic devices. Yes, if we like the car to be fast in corners, there is no alternative. Or else, we are stuck in stone-age corner speeds. Without down force devices we could newer corner much more than 1-G (street tires). Correctly engineered air devices also improve straight-line stability. Even at regular road speed of 60 mph we should theoretically be able to raise cornering G-s by 10-15 %. Downforce racecars. Mulsannescorner databas, great racecar info.

The original location of the rear wing. If one want it for looks only, this is OK. It stays within the size of the car itself. Check the wing location of a Trans am car!	New test location of the rear wing. In fact, now it begins to make some good. The angle of attack is a shot in the dark, and gives 150 pounds of downforce at 94 mph. Adding 8,5% tracktion at the rear wheels. From here I will go on testing.	Lola, good ecample of aerodynamics.	Rear wing aft of the car!

My own design front hood. All air passing through radiator is coming out here. I made this for my first Pantera. Altrouhgt this on is used on Bjorn Carapis 219 mph car.He did not experience any speed front end lift.	This is the cooling air outlet director. A single powerful fan from Audi fabricated by Siemens, is used.	Aero test.	No doubt, the air is flowing out the "window", and the engine bay is refilled from under the car. Speed is 40 mph.

The new hood was 4,7 kg or 10,34 pounds. The original was 17 kg or 37,40 pounds. Then we got a few things more spared on the car weighting 1,7kg or 3,96 pounds. For a sum of 31,02 pounds.	This air outlet was tested on the Pantera in the full scale windtunnel of Saab in 1986. We should see if it lives up to expectation.	Fabricating a new front hood in fibreglass.Sandwished with bonocell layer.

The undrside is almost flat. There is an area where the jacking stand is placed that is still open. (I has to hawe wheels). And far back under the engine. The first wersion splitter pulled 50mm of water in the middle of the car, at 75 mph.Underside flat surface is 36000 cm2. We will see what this splitter will do.	Rear diffusser of Ferrari F1

Brakes.

More horsepower in the car it is often said that one must follow up with more brakes. I agree, but with a few corrections. Street speed depend more on the driver (if he like to keep the licence or not), than on engine output. If a 3000-pound car is to be stopped from 100 mph, we need brakes for that purpose. Not for how fast the car can reach 100 mph. On the racetrack more HP always result in a rise of the average speed, as the car always is used to its limit. Race car drivers knows exactly where to go off the throttle and start braking. This is not the case on the street. Road, sports car drivers must use a safety margin. This margin makes for more cooling time. So, I will not use bigger discs than just what is needed to prevent from overheating. Unnecessary disc weight reduces cornering power on rough surface road.

I will use the very best low temperature working pads. And no bigger or heavier calliper-pads than needed for even pad wear. The master cylinder system should be balanced for the callipers used. Of course, one can make a few laps at the track. And some very fast laps to, before it is time to stop and cool the discs down.

.

With this in mind I designed the brake components to make a light combination. Therefore, although weaker than iron, aluminium callipers is used. Aluminium has a flex module of 10 and steel 30 million. I use one piece and closed back type calipers. I fabricated this one-piece aluminium hub (image) to mount wheels, discs and front wheel bearings. Discs are Lockheed, 20 mm ventilated. Until now I had no experience of overheating (on public roads). It may also be possible to use solid discs (only for the streets) as they offer slightley better stopping performance because of better clamping support, and are less prone to cracking. Great feature for one big high speed stop to zero. An often overlooked factor is to use the right type pads. The right pads makes the original Pantera Girling calipers more than enough for any street Pantera. The only problem is that they are heavy. Two important brake factors is, ALLWAYS a yearly change of brake fluid and the right pads.

ISR brakes.

Powerfull braking, measured in G-force, is a complicated story, greatly depending on how the tires is loaded under during retard. The reason racing cars use huge brakes are to withstand repeated braking. In a way that newer occur on the streets. Big size calipers and fat discs does not produce higher braking G;s. No matter how big, red-painted and racy look the brake system is, it is impossible to create more stopping force than the available tire friction against the road. Pad area does NOT affect braking torque. Big discs and calipers does NOT create tire friction. Heavy braking force is a question of downforce, car balance, tires and a matching brake balance. So, very much attention has been paid to this matter, and, by making use of all four wheels and not only the front wheels, to stop the car. As known, the biggest rubber area is on the rear wheels of the car, and accordingly, in my case, they should carry 1560 and the front tires 1040 pounds during 1 G of braking for optimum braking power. But in reality the car produce a weight distribution that gives 1144 rear and 1456 pounds at the front axle, or 56% of the weight at the front wheels at 1-G. Briefly, this will lower the tire-Cf and thereby reducing braking capacity by 5-10%.

A Porsche GT-1 will brake around 1,05 G over 100-0 km/hr. However, from 200-100 km/hr I am heavely beaten by the GT-1 as this car has better aerodynamics.

Physics of braking

Wheels and tires.

Wheels are original GT-5 Campagnolo 13x15 and 10x15. Today 15-inch tires are hard to find. Hoosier and Avon still makes suitable rubber. There is a trend to the use of larger diameter wheels and lower profiles tires. This is just a trend, more than a good tire. After speaking with some of the leading racing tire manufacturer, I can assume that a tire profile of 40-45%, is about the best. Compared to spring wheel rate, tires usually has a rate of 1000 pound/inch. Tires also have a very good self dampening caracteristic. The tire spring work is also performed with almost non existent unsprung weight. And do not suffer from bumpsteer, camber change or the like. As long as my suspension and brakes does not call for more space, I prefer to use my 15 inch wheels. To take advantage of the tire side wall flex. The Campagnolo and racing tires also makes a very light combination, and wheel weight is of vital importance for a sports car. One rear wheel is 39 pound. The wheels is a unsprung weight that must be controlled by the shocks. A rotating mass, that must be accelerated in both rpm and distance. 250 pounds of wheels on the car is no thing but a serious sportscar destruction. One may perform quite good ski pad numbers with low profile-heavy tires. Do not let that misled you. Ski pad course usually are flat. Just wait until you hit a series of unexpected bumps in the middle of a fast road bend, and you are off the road. The Avon racing tires is of bias ply construction. This has both bad an good sides. They are more tolerable to camber settings, but has greater slip angles. This means that if the camber is not perfectley adjusted for a specific road, one will be faster than on radials. But it may confuse ackermann and toe settings.

Tire pattern. Cutting tire pattern. I just use the same as what could be ordered from Avon. There must be a pattern, and it will hopefully do some good if I happened to be stuck in rain. The Pantera cannot use a front tire larger than 600mm (23,5"). Which makes 15-16 inches wheels the most suitable. Of course, one can use 20 profile tires or raise the car to create the necessary spring travel. But these types of rubber and settings should only be used for show, not for those who like fast cars. Most of the big wheels is billet stuff, which in most cases makes the wheel by fare to heavy for anythig but look.

Wheel alignments. All measurements is on the wheel (15 inch distace). Rear wheels has 2 mm toe in. 1 mm each wheel to the middle line of the car, and 5 mm negative camber. Front wheels has 6 mm negative chamber and toe according to driving situations.

Caster. Pantera is limited in caster angle. This is taken care of by the new front suspension that uses 1 dgr Sai angle, then caster is only used for driver feel response and straight line stability.

Bumpsteer. Pantera is well known for bad bump steer. The new front suspension has zero bumpsteer over the used spring travel.

Ackermann. Is an interesting object. Especially with the larger slip angle of the bais ply tires. That may vary the "effective" toe setting by 10 degree during cornering. 100 % Ackermann is used on regular road cars, while "racing" Ackermann depend on tire slipangle. High speed cornering could use negative ackermann, while tighter corner should use positive Ackermann.

Friction area. A lot myths is circulating around tire dynamics. But theese are physical real life testings. The figure below show tire contact area in kg per square cm. At a tire inflation pressure of 2kg/cm2, or 29psi and 500 kg (227p) of load, we got 1,9 kg per cm2 of area. If we lower the inflation to 1 kg/cm2, (14,5pis), the load per cm2 will be reduced to 1,42 kg/cm2. If we divided 500kg by 1,90kg/cm2 we get 263cm^2 printarea. When lower the pressure from 2 to1kg cm2, we got 500/1,42=352cm^2 print area. So, half the iflation pressure gives 34% larger contact patch. A note, the tire does not carry the same load over the contact area, and the contact area is not in direct proportion to inflation pressure. A big amount of the advantage of wider tires is that they should be used with lower pressure on the same car.   This is the foot print of a 10 inch-left and a 13 inch-right, wide tire. During the test both tires was mounted as a rear wheel, carrying the same load. . Both tire has the same diameter and a tire pressure of 25 psi. As can be seen, the wider tire show a shorter but wider print. The 10 inch tire has a print area of 308 cm2 and the wider tire 340 cm2. At a load of 880 pound

Rollbars springs shocks and A-arms.

Rear suspension.

The coilower is mounted in front of the front upright bearing. This makes the weight of the car to mainly load the front upright bearing, placing a smaller load in forward direction on the upper A-arm. The rear bearing does mainly support acceleration and braking torques.

Second version. Better bolting pattern to the chassis ans smaller outer bearing house.	Rear upper A-arm. Made to match the new front suspension.	Left. When making toe or camber adjustment, just unbolt the front leg of the A-arm. When alignent is fixed, adjust the length to suit the new angle. No bindings then.

My new (own fabrication) uprights.This is a "BOX" casting. With no open sides. This makes a tremendous difference in twisting stiffness. This one weights 8,8 pounds. Original steel is 13.75 pounds.	New A-arm layout. This should make room for larger exhaust pipes. It also has the benefit of greater stifness to distribute vertical load to the rear bushing of the uppright..	Tightening rear axle nut.

Construction sketch. The shaded area is the stainless bearing holder. (Pictured above with the outer bearing mounted. The bearing play is set by shims between the axle yok tightened by the axle nut. There are two sealing boxes outside each bearing, running directly against the inner bearing race. Even the inner bearing must have a turned seat in the upright. What cannot be seen on the drawing is that the inner bearing has a 1/4" smaller outside diameter, but is slightly wider.

Combination of needle roller and ball bearing for the lover uppright axle makes for an exact suspension movement.	The axle tube is fabricated out of bearing material and is the inner roller race.	Halfchafts. The one on the top is factory lenght. I cut 1,2inches away from the big end. Exposing a longer portion of the smaller diameter axle. This makes more room for exhaust pipes, plus saves 1/2 pound.	The upper ball joint is an sperical standard bearing. A special insert locate it in the A-arm.

Front suspension.

Front A-arm system, longer arms, more parallell and thereby less camber compensative. 1 dgr spindle angle.		Bumpsteer adjustment at steering rodend.
Spindle parts. Lover balljoint is Saab.	Caster is schimmed to spec.	Upper spindle joint bearing and bolt.

Sway bars, are commonly named "anti sway bars", which sounds like the whole idea behind the bar is to protect the car from sway. The sway bar is a balance tool, f,ex if the road is wet we may need some more front end grip. This is achieved by reducing the front bar rate. Or, should we say, allow the car to roll a little more. In other words, more roll - better grip. The spring rate of the bars together should be just high enough to give the car a suitable "sideway spring travel". Without making the suspension to bottom out. Or to prevent ground contact, during cornering. A good set-up "sideway suspension" help even out corner peak loads, not to chock the tire grip.The spring rate balance between the front and rear bars should then be used to balance over-under steer. The drawback of to much roll is gain in positive camber . The harder the bars, the harder the outer tire peakloads become and the tire heats up more. I use a spring rate soft enough to permit a roll of a roll of 1,5 degree. It is also worth mentioning that different roll bar stiffness does not affect the amount of weight trasfered to the outside wheels during cornering. I will only affect the distribution of weight front-rear, and how hard the transferred weight will hit the tire grip. The transferred weight is a product of centre of gravity height, track width and speed. Shocks gives this movement a "time factor". To take full advantage of the roll, A-arm angle are very important for proper roll-camber and road contact. Hollow swaybars? The rear bar of the Pantera weight 8,8 pound. A hollow will save 5 pound for the same springrate. Pantera swaybars is located at the lowest point of the car. So there is no value for the money. I rather use the money to reduce both more and hihger located weight in the car.

 Weight transfer

The front sway bar of the Pantera has a spring ratio of 0,16. This means that the bar spring rate are to be multiplied by 0,16 A bar with a spring rate of 650 pund/inch, times 0,16 is 104 pound/inch at the wheel. The equation is, bar attaching point length = 135mm A-arm length = 335mm equals 0,40. 0,40x0,40 = 0,16. Rear motion ratio is 0,70. The same is true for the springs. Motion ratio is 0,71 front and 0,75 rear. Just multiple those numbers with spring rate and you got the wheel rate. To calculate motion ratio for the springs, the angle of the coil over must be taken in to consideration. However, this numbers does not apply to my new A-arms.

Spring wheel rate. Are 386 pound/inch front and 585 pound/inch rear. I am talking wheel rate, as this is the rate the car uses against the road. Wheel rate is less than spring rate because the lever of the A-arm. Divided by the car weight we get spring frequencies, a number that show how hard the car is sprung. This numbers are 3hz front and 2,8 hz rear. Together with the roll bar this balances the weight distribution off 62 % rear and 38 % front to almost neutral steering. Equally important are where the masses is located on the car. And they should be located low down and in the centre of the car. Ideal for the Pantera since it has no ground effect. If there is anything I really miss on the car, it should be a better design under body. My first Pantera was even heavier in the rear, 66%, and accordingly show better braking numbers, but more sensitive to tune in corners. Shocks are Öhlins.

	New shockabsorbers from ÖHLINS.Supposed to be about the best there is. We will see the comming season.This set up is fabricated specially for the Pantera, with shims and springs for my car. I decided to sort out a racing set up, so the car is sprung to 3 Hz as a starting point

Racing cars use very hard springs, and close to ground settings. Racetracks usually are very flat. Apart from regular roads where you meet all kind of obstructions, different surfaces and up and downs. I use a ground clearence of 3 inches. This is about as low as I can get with a resonable spring rate. Even with 3 inches I had a few ground connections. For the same reasons, bumpy roads, a streetcar can take advantage of its lighter brake equipment, to make the wheels follow the roads better. Therefore, to be fast on the roads, stay away from stiff racecar settings. Go cart feelings does nothing but slows the car down. It is not the way that firmer springs and bars makes the car gain road grip. It is the other way around. It makes the car loose grip. When the a car is tuned faster(more road grip), usually by lower CG height, geometric, wing and rubber actions, the car must use more springs becouse the added speed capability put bigger loads on the car. Ok, depending on A-arm geometry we might want to stiffen the car to retain proper camber angle, but thats strictley racing stuff.. Therefore we should newer use more spring than necessary. As for references, the Panoz racing car has a front wheel travel of 10 mm drop and 25 mm bump. Rear wheel travel is 25mm drop and 40mm bump.

A-arm geometry.

Pantera A-arm geometry is not much to be proud of today, creating a miserable change in spring-wheelrate and a few other undesirable effects. F-1 cars use long and very much parallell A-arms. That way we got insensitivity to camber vs ride height variation due to aerodynamic force without affecting camber compensation too much. The F-1 theory does not apply very well to this sort of sportscar, but some of the thinking is usefull. What I am trying to do here is to keep rollcentre height at the same level and GRc lateral movement under control in order to keep weight transfer and its distribution, geometric-elastic front to rear the same during roll.

Top, original Pantera front suspension geometry. With the low ground setting there is quite a steep upper A-arm angle. Also the lower arm has lower pivot centre in the chassis. Not the very best, allthrougt giving acceptable roll centre height. One other problem is the SAI projection point that hit the ground at 1290 mm distance, creating a big scrub radious.	Top, original Pantera rear geometry. Very short instant centre gives a "swingam" like wheel travel. Together with a large scrub radious, wheelrate is getting lower. I made up a formula, for use in an excel sheet, showing what happens. =(SIN(C2*3,14/180)*(B2*F2)/(A2*(F2+E2)))^2

The new A-arm geometry, front. Rc at 11,2 mm.	New rear geometry. Rc at 30 mm.

This is the FRONT suspension. The geometry used is such that the roll centre height is keept within 0,2 mm during 1,5 degree of roll. Also, the jacking forces are almost neutralized over the left and rear sides, so very little lifting movements are present. This means that the rollarm remains pretty much constant over the roll-movement. 1,5 dgr of roll means 0,8" of deflection, or 20 mm. With that in mind I set the rollstiffness so that I got 20 mm of deflection at 1,3 g of cornering load. As the CGH is 415 mm or 16,3", I got 415-11,3=403,7mm rollarm. Sprung weight is 1000 kg. 1000*1,3g =1300kg. 1300*0,4037= 525kpm of Mot.

This means a rollstiffness of 404 kpm per degree. Total Wt = 415mm* 1,3g *1220Kg/1560mm=422kg. The outside pair of wheel is then carrying 1032 kg which means 85% of the side load. As seen in the drawing to the right where the car is under roll, the geometric Rc has moved 73% of the Tw to the unloaded wheel side. Idealy it should have been 85% according to the Wt number. However, the forcelines are low so the height difference at the side of GRc is low, which show the advantage of low forcelines. To cure the problem I could lower the Cgh to 300 mm, which is not easy. Another solution is using more parallell A-arms but then the cambercompensation situation is getting vorse. Low forcelines and long A-arms does also gives the benefit of less lateral scrub during heave, good braking nd acceleration grip from less vertical movement-camber change, or if aerodynamic downforce is present. Low Cgh is mandatory from all points of view.

The rear suspension is not showed, but A-arms are shorter and thereby victims for a larger compromice. GRc is only moving 195 mm resulting in a larger jacking force. I tryed to keep the cambersituation as equal to front as possible and the outside front is -1,28 compared to the rears -1,4 degree @ 1,5 dgr roll.

This is a model used to check out body-roll depending on Rollaxis angle. I has been a lot written and talked about this phenomenon, but I dont know if things are sorted out. Computer program is great, but to me a physical model is very dependable, and this model is able to handle both right and left tire grip load, which is very important since load affect jacking forces. As the model is set up here, we are having a very high Rc in one end of the car and an almost ground level Rc at the opposit end. In this case the model show that weight distribution front toreae has an influence on the precentage of geometric antiroll of the car. However, this setup is not really used on any car, but it show the principals we have to deal with. Using longer and more parallell to ground A-arms at all four corners will take the hazzle out of the calculations and make it much easier to deal with. Even if the term Rc appear a bit dizzy, in reality it is not. With a properley designed A-arm system Rc can be pretty much fixed at the centre of the car even as the GRc is moving sideways. Rc is useful for establishing the rollaxis.

New Pantera design.

Recently there was a new design, or should I say new dressing, for the Pantera made by someone thinking it needs a new look. Ok, from my point of view, the look should remain pretty much the same as before, although 2 meters wide 1 meter height and 4,1 meters long and some modified fenders for larger wheels, as fare as design is concerned. Then the similarity will end, a totally redesigned chassis. Front track 1670 mm, rear track 1645mm, wheelbase 2500mm. Ground setting 70mm. Rch 15mm, Cgh 300-350mm, weight 950kg, zero antidive and squat, Front and rear SAI 1 dgr, scrub front 15mm and rear 20mm, 30% Ackermann. Brakes are 12" discs x 1,25. Hight mounted rack and pinion which takes another A-arm layout. This will do away with roll and bumpsteer troubble, and at the same time get rid of any 3:e A-arm leg influence from a steering rod monted in between tha A-arms. Pushrod suspension. Front and rear frame lower tubes together with the A-arms is using a higher location in order to house an aerodynamically efficent bellypan and diffusors. Totally new design spindles and upprights located in a way that reduces internal loads and also on both steering rods and rear toe leg rod. Pushrod angle and location is such that A-arm load is greatley reduced. Rc is adjustable by horizontally mounted inner A-arm bushings and spherical bearings is used in moost cases as they permit better forceline centre in the A-arm legs. But even a few heimjoint is used for adjustability but mounted in such way that they recieve straight loads. I was figuring the car should be right hand drive as European tracks are mostley running clockwise. The floor is marked green, and the feets will be higher becouse of the raised front structure. A-arm attachment are blue, rack&P is yellow and wheelcentre red, just so we can compare to the original Pantera locations. The scale of the drawing is pretty exact, but is only showing the main tubing for simplicity. Triangulation is very much left out.

Photoshop image to visualize what the Pantera may look like modified according to the drawings. I didnt put to much effort using Photoshop, just eough to get an acceptable image. Front air dam is moved forward for better splitter function. Wheel house openings are rounded and moved up. Wheels are 18". Car is 1000mm in height. And the diffuser together with radiator air exit out the side. Rear diffusor added. The intention is not to create a better looking Pantera but to house a racing chassis in a body still looking as much as an original Pantera as possible.

Corvette C6 and Viper suspension.

As for comparsion I made a scetch of the Corvette and Viper suspension system. One might wonder what the engineer come up with for those cars as they provide a fairly good ride while still maintaining braking, cornering and acceleration performance that good. There is a lot to be said for a comment to these drawings so I want go in to details, but so much can be said that those cars are quite soft in heave and to cope with horizontal forces they have a good deal of anti:s in all directions. The Corvette is on top and Viper below. To the left we have the front and to the right the rear suspension. Middle part is the cars seen from the side where the CGH line is common for both cars for an easy comparsion and the wheels on the sides is seen from the rear or front. I was figuring of making a Ohlins coilover setup for these cars if time so permit. The idea is to create a sporty set up more suitable for road racing.

A-arm geomerty

Performance.

Skipad driving. This is what the car looks like under 1g of cornering. The car should be driven in a circle along the white line. Lap-time is measured with a photocell My skipad test, with the GT-5 in stock condition with the 351-C and original wing location, could hardley corner more than 1.G. Clearly showing that the Pantera aerodynamics does not work. A Penske indy car has 3300 ibs ground force at 165 mph, at the cost of 1119 ibs of drag. A cart-car with well designed wings can turn 4 g:s. Porsche 911 has a lift of 600 ibs at 150 mph. Ferrari Enzo a has a downforce of 760 ibs at 125 mph with NO wing, due to good under body. And corners 1,4 G. Numbers that speaks for itself. Koenigsegg, claim a cornering capability of 1,15g a great number, but still 0,25g lower than the Enzo. Both Enzo and Koenigsegg talk "cornering capability", which should not be confused with skipad numbers. A corner is a corner and skipad is a complete 360 circle. So the 1,4 and 1,15 g will be reduced on the skipad.

Specifications.

Wheel loads at different actions. Original Pantera estimates for comparsion.

Wheel alignment.

Weight and weight savings.

Weight. 2600 pounds. My first Pantera was 2398 pounds! With a 500 cui Ford. With the 302 boss it was 2343 pounds and made the quarter i 11,7 sec. Why is the Hemipanter carrying around with 202 pounds of extra weight compared to the 500 Ford installation? Second, is it really possible to come down to 2398 with an IRON block big block??? What is the secret? Answer, there is no secret. Drill holes in every bolts, plastic windows, fibreglass hoods, small battery, no frogeyes, etc, etc. Concerning the Hemipanter, I was in mind to keeping it kind of original. Putting on some heat when chilly. In a few words, I liked this car to have at least some kind of comfort and appear original.

Karbon fibre rear deck lid. 13,2 pounds yet very strong. This particular hood had a sew problems like to bent roof profile. I try the trix of bending it straight and reinforce with fibre glass. It has gelcote on, so it has to be painted. No carbon fibre show off, to bad. Very light doors and even the door hings are lightened.

Corner weighting.	A sports car should always be cornerweighted. This is important for the balance of the car. This weighting was performed 18 july 2008. The car showed to weight 1179kg wich I am quite pleased with.. The corner relation is not the very best and the sideweight could be more to the right side concidering there is no driver in the seat.

Interior.

Carbone fibre dasch, the onlything "bling" on the car.

Pictures 2004 season

12/8 Testing day at Lunda airport.I rented the track all by myself for a 10 hr hard driving day.
Henrik from Ohlins keeps reckord of shock settings.	My little daughter is having fun with a go cart.

PederPanter

Started out as a rust bucket in 1986.	The rear end was supposed to be wider, so I cut it in the middle.	Rear fender cut away.
The front was tilted down some 3 inches.	Rusted out door panels is exchanged by new ones.	Widening sheet metal was welded in place. 1989.
15 years later, the car was finally painted.	All new lowered floor.	Painted inside out.
Pantera caliper with hanbrakes!!!	We did need wheel spacers for this application.	Aluminium gas tank.
This Pantera electrical system is very basic 1970 stuff. Still very clean compare to the original mess. One connector to the engine.	Dynamat everywhere.	this is all electrical wiring there is in the engine compartment.
The alternator is newer one lead activating unit. Tightening the belt is done by a lef and right hand tread bolt. The attaching conector on the engine side is beside the alternator. The black is for the distributor.	Timing is handeled by MSD advance curve unit and amplified by MSD6 AL.	An fuel opening was fabricated according to original later Pantera.

1 Peder decided for a stereo in the car. This call for a small bass cabibet.	2 Painted black and 2 crossover drossels.	3 Two 8" Altec Lansing speakers mounted.
4 The bass cabinet in place..	5 A very small and easy to locate stereo panel.	6 Pioneer and Rocford Fossgate amps. There is also a Brax condesor for peak transient note power supply.
7 Treble and midrange speakers mounted on side panels.	8 On the right side the speaker panel is a combinatipn of speaker-fuse cover.	10 Left side is speaker only panels. The speakers appear almost non exsistent in the car. On advantage of the placement of the speakers is that the stereo picture gives both the driver and passenger a perfect "middle" feeling.

Splasch guards in the fender housing is a must.	Both front...	and rear.

Engine installation	The chain is strapped to the rear manifold bolts.	Making for a pretty good frontweight balance.
No problem tilting the combo a little extra.	No lifting chain to roof problems.	Easy to work throught the large fiore wall opening.

Books

A chassis engineering book that show the build up of the Speedlab Corvette race car. This is a book about how to build a racing car. I describe the process step by step, using the build up of a racing Corvette as a working example. For those who like Corvettes this might be of special interest. I am using a building theory of my own called the "Zerocar" philosophy. The Zerocar is a car that has practically no suspension angle's, ground level roll centre and no anti's. What makes a racing car faster than a production car around the track is that it is optimized to do what it is set to do. A daily transporter must be able to do a number of things and be able to drive in sun, rain and snow. The race car will become a nightmare in snow. This means that the daily driver is having a number of features that has no place on a race car, and will therefore not be very good to use as a platform when explaining the building process. The Zerocar is a "clean" car where we only need to add what is needed to make it suit our application, no less, no more. The second part of the book is more about calculation, math, tires, wheel alignment, suspension geometry, springs, swaybars and a quite large section about shock absorbers. Everything very much down to earth, to make it possible for a small team to build a fast car. The book is in English. A4 format, 202 sides and 250 images. Interested? Drop me a mail with your name and adress to hemipanter@hemipanter.se Payment should be done in advance using PayPal, to the e-mail adress hemipanter@hemipanter.se $ 85. € 59. Including shipping. Price in Sweden are sek 510:-, since shipping is less costly. Dont forget to mail your name and adress!

Varför behövs fjädring på racebilen?

Banan är mer ojämn än vi kanske tänker oss till en början. Vi kanske inte heller tänker oss att komforten spelar så stor roll i en racebil, men faktum är att en helt ofjädrad bil skulle bli extremt okomfortbel för föraren. Vibrationer som inte heller vore särskillt gynsamma för mekaniska komponenter skulle uppstå. Men, allt handlar inte bara om vanlig fjädring, vi vill att alla hjulen skall ha vägkontakt. Jämför vi då siuationen med en stol som står på ojämt underlag så kommer ett ben att inte nå marken. Hjulen behöver alltså ett mått av rörelsefrihet i form av fjädringsväg för att situationen skall bli den bästa.

My two chassis dynamic books, universal chassis setup book "Väghållningsboken" and the , Suspension construction book, for those who want to build their own suspension system. In the supension book I am presenting a theory that explain the reason for using different A-arm lenght and angle, in order not to alter the load transfer between the front and rear axles. Also, the rollcentre and roll axle phenomenon is deepley described. Sorry to say that both books are in Swedich language, but I am trying to find a way of making a good translation. (As seen on this site, I should not do the translation myself).

Mina två böker i chassiedynamik. Väghållningsboken behandlar väghållning i allmänhet. A-armssystem o fjädringsberäkningar, däck och stötdämpare. Beräkninar för bromssystem och grundläggande bromsfysik är ingredienser i boken. Även lite aerodynamik och hur undersidan av bilen med splitter samt en vinge fungerar, men även lite motorteknik som kylsystem, avgas o insugningssystem och torrsusumpsmörjning finns med.

Hjulupphängningsboken gav jag ut för ett halvår sedan men upplagan visade sig inte särskillt bra. Nu har jag reviderat den totalt utifrån den respons jag fått från läsare. Boken behandlar enbart A-armssystem för den som vill designa sin egen hjulupphängning eller få en djupare insikt i hur det fungerar. Boken innehåller även teorieri om orsakerna varför man väljer vissa längder och vinklar på ett A-armssystem vilket lyst med sin frånvaro i många skrifter. Kulleder, materialval, profiler, pushrods. Beräkning av lastväxlingar, rollaxellutning, samt ingående anlys av "anti" funktioner och rollcentrum.

	Shock Absorber curves from my new book, "Race car Chassis book".   This is the front setting of my own dampers. It is two runs with the same setting and the difference is due to normal measuring circumstances. Dotted line is rebound. The compression is harder in setting, which is a typical hard driven road sportscar or racing car feature.
	Rear setting is harder at low piston speed which is due to the tail heavy mid engine configuration. The suspenion spring Hz number is less for the rear.
	Here we can see what happen with the rear curve when compression setting is changed from 2 - 24 click, while the rebound setting remain unchanged.

Corvette Nordic Supercar

Speedlab Corvette Racing 2008.

The Nordic Supercar is an interesting cup with big, fast powerfull cars using V-8 snd V-10 enines. The Speedlab Racing Team have given me the confidence to design their new Corvette racing car from a clean sheet of paper.The old car is the yellow Corvette to the left, which is an USA built C-3 Trans Am car from the 90:s. Me, standing, and the Speedlab guys loking at drawings.

Planned design of the car.

Drawings.
Me showing the basic drawings.	Breif design of the front wheel centre line cut seen from the rear. Engine is offset to the right.18 inch wheels 13 and 13,5 inches wide, 650 front and 710mm rear diameter tires from Michelin. Total height 40 inches = 1000 mm..
Upprights and spindles.
Here a prototype front and rear upprights made from cartoon paper that is going to be fabricated in chrome molly steel. Chrome molley sheet metal for the rear upprights.	Chassis twistng. This is the twisting test of the chassis. The front bar is anchored to the floor at the outer end and is resting on a floating stand in the middle, all to elminate bindings. The "starting out" twisting showed a mear 4000 fp/dgr, where the largest nuber was read in the engine section of the chassis, and the roof as a good number two. After crossbracing the roof and mounting of the engine the number went up to 8000Nm/dgr. Bar is 2 meters long for an easy Nm reading. The centre of the rear is also ancored to the floor, hanging in a wire. The chassis is lifted up from its "resting" location during the test. By using telescopic tubes I detected the largest flex to occure in the front window area, 1/8", so an diagonal tube was welded in place as seen on this image. Now the redaing get 18000 Nm/dgr. We still got a 1/16" flex in the engine section, and the coupe floor that is describing "waves" under loads. I am looking for (hopefully) some 30000 Nm/dgr as a final result.
The height of the car. Speedlab teamleader Mikael Karpers is checking the chassis out... Before and after sectioning of the rear body. Roof rollbar is hardley over the rear bonnet! Looks like then USA gt1 cars is to high, original door side height i almost at chassis roof level.	After sectioning its fully wisible.   The same seen from the side,
Engine.   Evacuation permits very short hoses to the pump. The low mounting location does also ensure good starting up oilpressure. Oil evacuation permits very short hoses to the pump. The low mounting location does also ensure good starting up oilpressure. Showing HM damper and oil pump drive. I made a new hub with a longer "neck" to be able to mount the belt-drive-wheel on the inside of the HM-damper. Pump is as low mounted as possible.     Header fabrication. Image also show the low mounting of the oilpump and special bellhousing. Headers are seven-Y designe and is having a megaphone after the last Y.	Rear mounted starter motor. Oil seal arrangement on the engine side of the mounting plate. Removable cam trans cover with camwalk plate. Observe the custom cut oilseal!
Chassis images.
	.
Observe, I banned the use of any bent tubes in the new part of the chassis. The Old trans-am part (red) is and was full of them, which made it no (better) stronger than a wet dischcloth..
Barkarby Street Car show.	There was a street car show 31/8 2008, where the Corvett was shown by the Simonisze company.
Wind tunnel testings.
To find out the best wing profile and its location on the car, I performed asimple wind tunnel test. Here is a 1:30 scale model of a "fantasy" car, it has a front splitter and an adjustable rear wing.	This is the underside of the car which is pretty much like what is used on the real Corvette race car.
The weight is resting on a balance bar where the model car is on the other end in the tunnel. By moving the weight to the left we can see the downforce created by the car. The scale on top of the balance mounting show the air drag by pulling the springs.	This is the tunnel. A 200 mm diameter tube connected to a fan that gives an air speed of about 150 km/hr. What we can see in this simple form of tunnel is moostly the way of direction things turns out to go.
	One very interesting thing is the effect of the wing working together with the diffusser of the car. I could easely say that its possition is critical for optimum downforce without creating to much drag. The Swedish tracks is not among the fastest, so a greater curvature wing like the one on the image to the left seem to be the best. I figured out a new design Gurney flap that we are going to test within a month on the track and I will be back later on with this.
This is one of 50 wingprofiles tested in the tunnel. The cord is 6,5 inches and spann 3 inches. I run with and without Gurney flap. On the car we will use a wing with a 400mm cord and exactly 2000mm spann.
Everything about how to build this car is in my book "Racecar Chassisbook" The book is $85 plus shipping. Give me a mail to hemipanter@hemipanter.se for more info.

This weight numbars would make for a great Pantera race car. To bad there is no money handy for such project.

The problem is what happens when two springs are loaded against each other. There is a plate C, between them and we are trying to push this plate to the left press one spring together. The springs are having a rate of 1kg per mm each.

A1, both springs is just touching the plate, which means that as soon as we push the plate in one direction it will produce a resistance of 1 kg per mm, and the other spring will come loose.

A2, If the plate is pushed 10 mm we must hold it by the force of 10 kg then. The opposite spring is is out of influence as soon as the plate is moving since there is no preload in the starting position.

B1, here both springs is having a preload of 10mm, a force of 10kg each. We are now trying to push the plate to the left again.

B2, the question is wether or not the right side spring by its pree loaded force will help us pressing the left spring together. What will be the needed force to move the plate 10mm to the left?

A new design of my guitars, the "Hemi Pantera guitar". Coloured as my Hemipanter car,. and of course, a few racing features like a fast fingerboard. They are distributed by "Tip Top Music" Stockholm.

Air scoop for the Pantera!

Rear hood hinger for easyremoval.