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VARIABLE MANIFOLD Description Entry Category: Product Design Inspired by my University dissertation (separate file) for improving the efficiency of older carburettor fuelled vehicles (in my case for a Triumph Spitfire 1500) by converting it to electronic fuel injection with a variable length intake manifold. The design has been revised to comply with the support-free constraint. The design can be adapted to various applications dependant on requirements and size constraints, the attached dissertation includes the calculations to design your own version based on your own vehicle! Purchased Parts List: • 2 x 75mm ID bearings to seal the rotary and static components (e.g. From: http://simplybearings.co.uk/shop/p170303/6215ZZ+Budget+Metal+Shielded+Deep+Groove+Ball+Bearing+75x130x25mm/product_info.html) • 1 x 42mm ID bearing to allow the manifold to rotate but the throttle body stay in position (e.g. from: http://simplybearings.co.uk/shop/p150426/F16048+Rubber+Sealed+Double+Row+Wheel+Bearing+42x82x36mm/product_info.html) • 4 x M2x10mm Socket head screw caps and washers to be used to mount the stepper motor. • Stepper Motor; uses the RPM output signal (processed through something like a Raspberry Pi) to determine the position of the manifold to ensure the right length for the given RPM to maximise efficiency. (e.g. from: http://uk.rs-online.com/web/p/stepper-motors/5350338/) All printed parts are assembled together and glued where necessary (i.e. Static Tube to Static Piece, all Variable Components together) Gear is attached to motor through the motor mount piece and meshed with the end piece of the variable section. A bit of calibration would be needed but should only need to be done once if the program is set to return to start position when the engine is switched off. The parts would be printed using either; Acetal, Polyethylene or Polypropylene so as to resist the ethanol content within modern fuels.