Porsche 964 Restomod - egmo 4.300 ccm - Eggenberger Motorenbau AG - Lothar Rothenheber, Urs Erbacher

37.20 minutes of werk1® tech talk, produced by autoquartett, Marc Freye: egmo 4.3 l, an exclusive sports engine based on the Porsche 964 Carrera 3.6 – its builder, Lothar Rothenheber, reports from his own perspective as "Spiritus Rector." Also in attendance: development partner Urs Erbacher. "We are building our 4.3-liter sports engine based on the 250 hp Porsche 964 Carrera 3.6. However, we use very few parts from the original base engine. To increase the displacement to 4.3 liters, we had to construct a new 82-millimeter crankshaft made of high-strength chrome-molybdenum steel, the same material used in high-performance racing engines. We succeeded in making the new crankshaft two kilograms lighter than the original. A new design of the connecting rods made of high-strength chrome-molybdenum steel was also necessary. However, since space is limited in the original crankcase of the Porsche 964, this presented a particular challenge. The pistons, like the cylinders, are our own developments. The cylinders are made of high-strength forged aluminum, and the cylinder bores have been recoated with the proven material Nikasil. The forged pistons run in the new, specially manufactured cylinders with optimized Running clearance for exceptionally smooth running with minimized noise. By optimizing the connecting rods and pistons, we have achieved a 170-gram lighter combination than the original. This is noticeable in the immediate throttle response, and is also crucial for the increased engine speed of 7,200 rpm. Since the stock cylinder heads offer very little leeway in the design of the intake and exhaust ports for optimal cylinder filling with comfortable camshaft timing, we once again had to go our own way. The cylinder heads are also new designs. They allow us to exert maximum influence on the port design and thus on cylinder filling. Of course, it was no longer possible for us to use existing camshafts. Therefore, we were forced to find our own approach here as well. The intake system with a single-throttle system using drive-by-wire technology and a two-phase variable intake manifold, together with the fully sequential ignition/injection system with twelve Single-spark ignition coils provide the ability to deliver over 400 Newton meters of torque starting at 2,800 rpm. The maximum torque peaks at 460 Newton meters with an engine speed delta of 5,200 to 6,200 rpm. To achieve all this, it was necessary to optimally adapt the exhaust system and the manifolds to the new conditions and circumstances. Here, too, a completely new development was unavoidable. Optimized diameters and precisely measured lengths of the individual pipes, together with the catalytic converters and the rear muffler, form an optimized unit. For the engine control, we rely on our long-standing partner Emtron, who supplies us with a customized control unit. This technology enables fully sequential control of the injectors and the twelve single-spark ignition coils. A bank-selective lambda control system, combined with drive-by-wire control of the six individual throttle bodies, offers us optimal adjustment of all parameters. Integrated data recording continuously provides us with the necessary information about the current state of the engine. The integrated CAN bus function also allows for the optional use of a multi-display with a data logger. 3,476 characters (including spaces and line breaks) Production: autoquartett, Marc Freye Editorial, Camera: netzwerkeins GmbH, Petra Pollmann Management, Concept: netzwerkeins GmbH, Carsten Krome werk1® tech data: the technical documentation in all relevant details. Vehicle type: Porsche 911 Carrera 2 Coupé 3.6, restomod of the Erbach 911 Sports engine: egmo 4.3 l based on the 964 Carrera 3.6 Displacement: 4.3 l (4,264 cc) Bore: 105.00 mm Stroke: 82.00 mm Compression ratio: 11.5:1 Engine power: 405 hp at 6,250 rpm Maximum torque: 462 Nm at 6,040 rpm Maximum engine speed: 7,200 rpm Transmission: OEM five-speed manual transmission type G50 with short shifter