Did find three suppliers of 4 inch throttle bodies for the 20b.
These

are

105 mm each (4.17"). Accufab number AB-F105TBOR, Holley has three,

and Edelbroke Universal racing #3877. The Accufab appears to be
the smallest footprint and possibly the lightest. Or am I missing
something?

Judging from a web search and until I can spend more time in the
salvage yards, 105 mm throttle bodies were never stock on any
engines. I would

like

to be wrong and save that cash for other things.

Wade Bush
Flying 20b to be

They are simple to make Wade. Here is a nice large one made by Chuck

Dunlap. You could also weld it up from aluminum tubing and plate.
Most commercial ones are way more complicated than needed in our
application.

Paul Lamar

wadebush wrote:

I was thinking that way (making my own) but starting comparing
time-tools-experience-education-stock and pieces-plan/instructions and

then decided to just buy one.  OK, I'll bite, does Chuck have more and

how much for a four inch model? Wade

I built mine as an excersize to teach myself machining on my new CC
(cheap chinese)mill and CC lathe.
It took about 20 hours to complete, not economical to produce the way I
built it.
McMaster Carr shows aluminum butterfly valves, the 4" model is $153.
http://www.mcmaster.com/catalog/109/html/0357.html#.
If it works, you might want add an idle adjustment stop.

Chuck Dunlap

wadebush wrote:

Thanks Chuck!
Wade

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.