Throttle Body Sizing

[Alexander M. Lichstein]

We had some success in boring out a block of aluminum with the throat size we
wanted, putting some brass bushings in as bearings with a steel shaft that was
made half-round in the middle with an end-mill.  The butterfly plate itself was
made on a CNC milling machine by - and here's the catch - mounting it on a
block of aluminum, and clamping that block at a 10' angle on the mill table. 
We then toold the mill to make a cylinder, plunging to a depth which would
circumnavigate the brass plate.  voila... chamfered edges, and the appropriate
oval shape to wedge itself in real nice.  Idle bypass can be done a number of
ways (simplest with some tubing and a petcock.  Not exactly a device I would
want in my street car, but just fine for racing.

- Z