Paul or anyone.
  Looking at the  Kinsler racing goods catalog I noticed that their
 butterfly throttle fully closes  14 degrees before  perpendicular.  Is
 this design point to keep it from jamming when shut?  Obviously the
 throttle plate then will not be perfectly round but an ellipse.
 Also does a throttle have to completely close?  Cold starts may be one
 reason perhaps but that is not such an issue with programmable
 injectors.  I am concerned because the high vacuum forces on the throttle
 plate may bend it unless I chose stainless.

 Doug in Japan.

 Yes that is what it sounds like to me.
 Usually throttles don't close completely as the engine needs
 air for idling. The carb idle adjust screw changes the throttle
 opening during idle. Not to be confused with the carb idle jet screw.

 Kinsler has some neat stuff so everybody should download their catalog.
 http://www.kinsler.com/page--HandbookCatalog--2.html
 Particularly useful are their bell mouths for intake runners.

 Paul Lamar



Many FI systems used to have idle air bypass - allowing the throttle
plate to close completely.  Air through the bypass is controlled by a
separate (sometimes feedback, temperature adjusting, solenoid
operated) valve.


Regards,

Matt-


Guys
Thanks.  I'll go ahead and make up a butterfly valve on Friday.
Everyweek I am logging ten hours in the school machine shop and it is
finally paying off.  Some parts however are faster to make from a rough
sketch and then cut to fit then pre design if you know what I mean. Real
world meets design world sort of thing:) Those parts will be documented
after their dimensions are fixed however.

Doug in Japan