It's been said there is no past or future but only the present which is a combination of all three. It certainly seems that way for the Beetle. The future Beetle looks like the Beetle of the past and now it seems that as time goes by, the present will always have a Beetle. This is comforting to know for those of us who just couldn't live without our Beetles..
Enough philosophy. Since the first "Dak To The Future" story considerable development has taken place. Building a car from scratch is very time consuming and at first comes with no noticeable results. This is even more the case when it is a race car because of the importance of chassis design in performance and safety.
The chassis and body have had to have several design changes before the first piece of steel was cut. The marriage of a Formula 2-style chassis and the L-model Beetle body didn't look good, then add some vague CAMS rules to the problem and you have three days gone just measuring and head scratching. However the results came eventually due to Tom Brickley's patience and experience.
The biggest design problem came from the engine as most open-wheel race car designs incorporate an in-line upright motor set-up. The flat four wanted to compete for space with the wishbone front end's pick-up points and the rear bulkhead which must be braced properly to resist twisting. All this is made worse by trying also to keep weight down by reducing the number of pipes without losing strength.
Having to add a separate cage inside the body and closely follow the shape of the body created a few more unwanted bars - every extra kilo is horsepower lost.
Starting with a blank sheet was good in order to have perfect suspension geometry. That's why the chassis is so narrow - to permit as long as possible wish bones and afford zero bump steer and dictate the desired amount of camber throughout the travel of the wheels.
By varying the
height of the wishbone pick-up points, antidive can be built into the front suspension and
anti-squat into the rear. All this will help keep the car stable and stop weight transfer
when the throttle is lifted and reapplied. The steering tie rods will be the same length
as the suspension arms so no bumpsteer occurs.
Materials and welding types is another minefield of seemingly conflicting information. After listening to all the different opinions it was time to do some reading and some looking at what various race cars are actually made of and for what purpose they are used. First the big catch words were "moly tube", "Reynolds tube", TIG, MIG, normalising, etc.
The over-riding factor is your interpretation of the word "strength". The final deciding point for me was, "how long will it last". For all the high tech materials and welding, this car has to be affordable, usable and feasible to be of any value. It would be nice to make a chrome moly or Reynolds tube frame and suspension, all TIG welded together, but considering cars made like that are worth big bickies and have a very short life expectancy because of fatigue if used to their potential. For crash purposes too we decided on mild steel because it bends instead of cracking and shattering. Someone once asked what were Porsche 962 chassis made of. The official response was "Unobtainium".
The "Welders Handbook" by HP Books has lots of technical information and more important examples of different applications. The Porsche 962 cited as extremely high tech with special metals and tricky welding in a car where a single component failure can be fatal.
So, mild steel was chosen for its availability, price and ability to last longer without fatigue. For much the same reason strength and durability reasons, a nickel and bronze mix is used to join the tube in a low temperature procedure that reduces metal stress and warpage at the same timers making repairs easier. At this stage it is interesting to note that some current English Formula cars have TIG welded chassis but use nickel bronze on their engine mountings and critical suspension pick-up points. Remember there are no right and wrong answers - only what works!
Volkswagen components have been used for all four stub axles and bearings for price, strength and availability reasons. They will also permit a wide range of brake choices from VW to U.S. made Willwood. The VW units will work fine but for weight reasons the aftermarket items would be the final choice. The prices are very reasonable for alloy four-spot callipers, which weigh 1.13 kilo's compared with 2.5 kilo's for the original VW products.
Vented discs and alloy mounting hats are also available. The master cylinder arrangement is a simple tandem set up with a dash-adjustable front and rear bias. Clutch is of the tried and proven cable type because of it's cost and feel. For drag racing and hard starts, a cable is preferable and it must represent a weight reduction over a hydraulic set-up.
The actual suspension itself is a typical coil-over-shocks set-up as you would see on any open wheel race car with shock rate and spring stiffness similar to that used on a Formula 5000 car. Considering the amount of regular and vigorous work planned for the car we went for the Koni brand. Spring and shock rate requirements are variable according to the conditions encountered.
Considerable time was spent sourcing the best price on all the components so that when the chassis kit becomes available, attractive package prices can be achieved for all the necessary bits and pieces.
Body working is the easy part of the project. A hacksaw and an oxy cutting torch will bring any VW body to the point where it will fit the chassis in question. It would be possible to fit an early Beetle, Super Bug, L-Bug or fastback body to the chassis we used. Like any VW, this chassis is completely drivable when independent of its body which opened the door to some possibilities. Custom bodies, fibreglass bodies and even a futuristic beetle come to mind. My long term dream is to take the plunge and try to build an all new beetle just like VW are trying to do but maintaining a rear engine, air cooled drivetrain.
Already Volkswagen have seen the light and put aero guards on the latest design study. A 0.30 drag co-efficient would be nice with some horsepower behind it. On Project Dak to the Future, a Celica SX air dam is being modified for the front bumper spoiler with a one piece bonnet, quarter panels and mudguards panel finishing just below the headlights to cover the front. Both will be "quick release". The whale tail bootlid and apron will be one piece while the rear guards remain separate. Again this is for ease of maintenance and replacement.
Track widths are 1425mm at the front and 1400mm at the rear with eights and nines being the wheel width. The front arch flares stay at the original 50 mm wider than standard but the rears are widened a further 50mm to a total of 100mm. Sport Sedan rules permit a 100mm increase.
The suspension geometry has been designed to run 23.75 tall front tyres and 24.5 inch tall rear tyres. This allows the use of 15, 16 or 17 inch wheels depending on the aspect ratio of the chosen tyres.
The big news I've saved 'til last - and that's engines and the heads.
As with the chassis, much development has taken place before being able to make a start. The new custom Type 4 head I've been working on has been designed and its manufacturing procedures have been finalised. I'm of the opinion that the Type 4 engine revolution has begun with lots of people already either doing it or preparing to do it. Porsche, Volkswagen and myriad European racers can't be wrong, it's an engine built for work. This head is tough enough to permit supercharging and Turbocharging of the Type 4 engine.
For the main part, the custom Type 4 head is perfect to allow a quick and cheap method of building a big air-cooled VW engine with moderate compression and a mild camshaft to produce reliable horsepower beyond that of a Beetle engine. The 2.0-litre Kombi motor can use a big cylinder head to produce more power with less fuss. When combined with twin dual-throat Dellortos and an electronic ignition the Type 4 engine needs only big valves to make it go real hard.
The constant shortage of new Type 4 heads at sensible prices has also prompted the need for an improved alternative.