The power transmission: a central, quite a challenging chapter.
Right from the start, the participants agreed on the exististing rear-axle tube. In view of the targeted 300 HP engine power, it should not be cut, no matter the circumstances. Therefore, the use of a longer Porsche five-speed manual transmission with the description „G50“ was not an option. Instead, intensive considerations had to be made, on how the Carrera-type engine could be associated with a four-gear-Volkswagen-Beetle gearing mechanism. The gear wheels of the VW Bus in South Africa design and the stiffer, more heavily ribbed housing seemed to be the most suitable. In addition, it was clear from the outset that the rear axle would have two semi-trailings similar to those of the Porsche 911 would be indispensable. Christian Wilms had been able to gather some empirical values because of his own VW Type 3. In addition, the Porsche variant would be significantly heavier than the previous. His approach: trailer arms which are welded to an inclined-steer drive stool and the assembly to cup-style struts. All of this was necessary to provide more stability, especially since the inclined steer drive stool does not have a frame fork. The transmission itself was not a problem. Christian Wilms had already bolted together some sturdy quarter-mile units and was confident that he could make the transmission durable for the expected maximum torque. The adaption of the gear ratio did not pose a hurdle either. However, the flange-mount of the six-cylinder boxer engine proved to be a real challenge …
Somehow obvious: major effort in the area of brakes and axles.
A short stopover in Burscheid, Germany: A motorsport specialist company is based in there, that has been machining chassis components from Sachs, H&R and Bilstein for 40 years. It had been exactly there, that Christian Wilms learned professional fabricating and milling. The contact could be maintained even after his own company was founded, and Rolf, as the Volkswagen specialist is pre-named, is also TÜV-certified – a basic prerequisite for the further procedure. All special parts had to be produced, including a strength certificate and the license to be able to manufacture such components at first. The installation of the braking system was based on a well-known principle: the journey is the reward, and many nights were bound to be long – or short. A similarly immense effort was required at the rear axle, not to mention the double wishbone front axle, based on a classic racing car. It made sense, however, because the six-cylinder boxer power unit with the Porsche-internal type description M64/01, which was rated at 250 bhp from stock, was to be given a few more horsepower. In brief: a programmable, digital engine management system, a special manifold exhaust system and a single throttle valve system with open intakes, which was still under development at the time and is now exclusively supplied by dtw germany | das triebwerk for many different Porsche engines. The result: more than 300 hp – in the retrospective, it is somehow obvious that a major effort was required in the area of brakes and axles.
Volkswagen 1,600 L, dtw conversion to performance version 3,600 L - inspired by Alexander Bloch.
Model year of the base vehicle: 1968
Body (standard state of delivery from the factory): sheet steel, structure on central tubular frame
Body shop (dtw | das triebwerk): complete restoration including repainting in “golf blue”; relocation and widening of the inner wheelhouses for later use of 16-inch Fuchs wheels; rear carrier comprehensively changed; engine mounts analogous to Porsche 911 (generation 964); adapted cooling air inlet; outside refueling in the front fender converted to inside refueling (analogous to model years up to 1967)
Lighting: front LED main headlights (Kaege, originally designed for VW Golf I); original rear lights
Electrics: custom engine wiring harness; original complete vehicle wiring harness
Basic engine: revised six-cylinder light metal boxer type M64 / 01 (MY 1991, version with cylinder head gaskets); two valves per cylinder; drive of the two camshafts via timing chain; specially manufactured dry sump oil container; oil level sensor taken from the Carrera 2 (964) and connected to the petrol tank display via a switch – selectable via a switch under the dashboard: The engine oil level can be read of the petrol tank gauge on the dashboard; engine control via DME (Motronic)
Engine structure (dtw | das triebwerk): individually manufactured, single throttle valve system milled from solid aluminum in a CNC process (adaptive, fits every six-cylinder boxer engine from 911 S 2.4); open intakes; open sports air filter; freely programmable, digital engine management; own manifold exhaust system with individual throttle valve system
Engine output (dtw | das triebwerk): 333 hp at 6,900 rpm from a displacement of 3,600 cc
Power transmission: manually shifted, modified four-speed gearbox from the Volkswagen Beetle in South Africa version, reinforced by stronger ribbing; reinforced gear wheels; Torsen-style worm roller limited-slip differential; custom-made specially rotated flywheel; reinforced, hydraulically operated clutch with adapted pedals; drive via specially configured drive shafts on the rear wheels
Brake system: original light metal fixed caliper housing type Porsche 911 Carrera 2 (generation 964); specially made / milled knuckle saddle mountings; special wheel hub parts made of aluminum, turned and drilled to fit the Volkswagen wheel bearings; specially manufactured brake caliper holder with TÜV approval
Wheel suspensions (front, series): double crank arm axle, transverse torsion bars
Wheel suspensions (new, dtw | das triebwerk): Bilstein “MDS” shock absorbers (MDS = modular damper system), adjustable in rebound and compression stages; reinforced torsion spring bars type Porsche 944 turbo; front conversion to double wishbone axle; rear conversion to semi-trailing arm axle analogous to Porsche 944; subframe rigidly bolted to the body; aluminum “cup” struts for support; trapezoidal reinforcements; replacement of the permanently elastic parts with specially manufactured versions with TÜV strength reports
Wheels: Fuchs (16 inch analogue Porsche 911)
Tires: 185 / 55-16 front and 195 / 60-16 rear
Interior: Recaro sports seats in a classic design; saddlery by Dzezmin Aliti, Cologne
In car entertainment: invisible sound system from “Dr. Boom “, Michael Zeitler
Empty weight (series): 920 kg
Empty weight (new): 1,036 kg
(Theoretical) top speed: 250 km / h (0.82 fourth gear)
Acceleration: 0 – 100 km / h in 3.5 seconds
Construction time: 9 months; 1,200 – 1,300 working hours