Chapter two: Water march!
Why sustainable investments in tangible assets made from sheet metal – from a professional point of view – do not belong in an acid bath.
Even though “amethyst” is a truly beautiful shade of red that originally adorned the coupé body of the 964, it was absolutely clear that in view of the extensive welding work necessary, the old paintwork would need to be stripped off. Background: before any welding work, the metal cloak has to be inspected for previous damage, possibly caused by accidents or corrosion. To do this, the metal should be completely bare and exposed. Only then can sustainable, long-term top quality be ensured. A gentle high-pressure water jet method is used for paint stripping. By dispensing with a chemical immersion bath process, no crystals can form and deposit in cavities or under the sheet metal seams that occur as a result of spot welding. In the long run, crystallisation can again lead to corrosion even on completely new sheet metal bodies. On the other hand, bare sheet metal without any chemicals is a guarantee for dependable, long-lasting work – and, incidentally, a real experience for project customers like Michael and Wolfgang. Both drop in once a week at dtw germany | das triebwerk in Schwelm to keep up to date and exchange their latest ideas.
Chapter five: Let colours speak.
Better: give them a code number that everyone knows what is meant: “aquamarine blue 5707” comes from the Porsche classic par excellence, the 356.
After sheet metal construction and at least 800 hours of welding, a completely new paint job – on one of the two “F350s” in a historically relevant colour: “aquamarine blue 5707”, a colour that had already adorned the first Porsche that went into series production. The second Porsche enthusiast opted for a more discreet shade of grey, which, unlike the first specimen in “aquamarine blue 5707”, did not stand out with a block stripe between two finer outlines. Otherwise, both (special) vehicles have the finely crafted, lockable oil and petrol caps in common, which come from the Harley Davidson motorbike brand range and are labelled with the correct operating fluid in each case for safety reasons: oil at the rear right side – as was the case with Porsche’s legendary “oil flap” in the 1972 model year, petrol at the centre of the front bonnet. A special mechanism ensures that the lettering is always horizontal. In addition, the tank system is designed in such a way that nothing can miss the target or get lost in the 87-litre petrol system. Incidentally, the centrally located bonnet fuelling system is one of 16 equipment options available.
Chapter eight: Walter. Approved.
Two-time rally world champion Walter Röhrl saw the performance of the two F350s for himself at the BILSTER BERG at the end of April 2021.
It is a special moment for a constructor, a partner and entrepreneur and their team when one of the world’s most respected volunteers takes to the cockpits of the two debutants – especially as he is also known for not mincing his words when need be. But Walter Röhrl, the best rally performer on the globe in 1980 and 1982, has surprisingly little to complain about during his first encounter with the two F350s from “das triebwerk”. Although he is astonished by the special characteristics of the previously described worm-roller lock, the statement so feared in the industry: “Go away with that rubbish!” remains absent – and indeed for the whole (Fri) day. Although the development and presentation driver in the service of the Zuffenhausen-based dream (car) factory gives the odd tip on fine-tuning the Bilstein sports suspension, he seems very satisfied with the workmanship of the two “restomods”, and this despite his generally blunt critical attitude. The same goes for their two proud owners, for whom the world champion’s blessing has something sacred about it – almost like Urbi et Orbi. One of them is already transferring his just ennobled new acquisition into his private collection, the other sees his choice confirmed – and is looking forward to one or two more active kilometres on the road. One would like to shout out to both: “Carry on!”
Chapter ten: The technical documentation.
The comprehensive specifications of all the measures and options implemented on the “F350” so far can be found here:
Vehicle type: Porsche 911 Carrera 4 coupé (model 964), dtw backdate to performance version F350.
Model year of the base vehicle: 1991 (M programme).
Base vehicle: version with steel sunroof and air-conditioning system.
Body (standard equipment on delivery from the factory): 2-door, 2+2-seater, self-supporting, closed coupé body made of hot-dip galvanised sheet metal on both sides in lightweight construction; deformable plastic front trim with integrated light-alloy bumper, attached to impact tubes; plastic side sill panels; rear spoiler in the boot hatch extending automatically at 80 km/h; deformable plastic rear trim with integrated light-alloy bumper, attached to impact tubes.
Body construction (dtw | das triebwerk): after complete dismantling, residue-free paint stripping using the chemical-free high-pressure water-jet process; checking of input dimensions on the frame straightening jig; set-up in the rolling rack; 800 welding hours including all modifications; widened front wings and rear side panels as well as side sill panelling made by hand from sheet steel panels in the proportions of the 911 S/T; replacement of the original central tunnel inside the car with a flatter version based on the F model of the early 1970s; F model conversion of front and rear including front and rear carriers; modified/widened front and rear bumpers made of sheet metal; front apron with additional front spoiler lip to enable a continuous baseline; enlarged engine oil and air-conditioning coolers in the cooling air intakes of the front apron; LED main headlights (Kaege).
Colour scheme (dtw | das triebwerk): new complete coating job in “aquamarine blue” (Porsche 356); block stripes in “savanna beige” with narrower outlines in “ruby red”.
Basic engine: reconditioned six-cylinder light-alloy boxer type M64/01 (MY 1991, ex works with cylinder head gaskets); two valves per cylinder; camshafts driven via cam chain; dry sump lubrication with separate oil reservoir; engine control via DME (Motronic).
Engine design (dtw | das triebwerk): individually manufactured, CNC-milled solid aluminium individual throttle valve system (adaptive, fits every six-cylinder boxer engine from 911 S 2.4); 993 generation valves with thinner 8-millimetre valve stems (compared to 9 mm on the M64/01 model); pistons with higher domes; new FVD cylinders; displacement expansion to 3,800 cc; Schrick camshafts; custom-made intake air manifold above the adapted intake spreader.
Exhaust system (dtw | das triebwerk): individually manufactured, CNC laser-cut exhaust system made of stainless steel tube material with two HJS 200 Zeller catalytic converters, one of the two exhaust manifolds is used as a heat exchanger for heating the vehicle interior.
Mixture setting: digital, freely programmable ECUMASTER engine control unit.
Compression: 11.8 : 1.
Engine output (standard on factory delivery): 250 hp at 6,100 rpm.
Engine output (dtw | das triebwerk): 362.7 hp at 7,800 rpm.
Power transmission: revised, manual shift five-speed gearbox type G50/03; original factory gear ratio; retrofitted worm-roller limited-slip differential (optional); single-mass flywheel; reinforced sports clutch; drive via double cardan shafts to the rear wheels.
Braking system: dual-circuit system with axle-wise split; four-piston aluminium fixed callipers front and rear (Brembo); internally ventilated and perforated discs (355 mm diameter front, 328 mm rear).
Wheel suspension (front): individually on light alloy wishbones and struts in McPherson design; Bilstein threaded shock absorbers “B16 PSS 10”; coil springs; anti-roll bar.
Wheel suspension (rear): individually on light alloy semi-trailing arms and struts; Bilstein threaded shock absorbers “B16 PSS 10”; coil springs; anti-roll bar.
Wheels: Bride alloy rims in Fuchs design (9J x 17-inch front and 11J x 17-inch rear).
Tyres: Pirelli “Classicʺ (235/45-17 front and 285/40-17 rear).
Interior: circular instruments with chrome rings; offset rev counter up to 9,000/min; individually manufactured and profiled bucket sports seats made of fibreglass-reinforced plastic with heating; gearshift gate with own components and others adapted from the G model G50; gearshift knob adapted from the F model with individually milled gearshift system; retro radio with hands-free facility; digital control panel for the air-conditioning system; rear-view camera monitor in the interior mirror.
In-car entertainment: largely invisible, individually manufactured “Dr. Boom” sound system with resonators under the interior door panels, correspondingly converted into a sound body.
Empty weight (according to DIN 70 020; standard scope of delivery from the factory): 1,350 kg.
Empty weight (new): 1,180 kg.
Total time required: 1,800 project hours.