Mailing List flyrotary@lancaironline.net Message #4828
From: Russell Duffy <13brv3@bellsouth.net>
Subject: Dumb intake question
Date: Sat, 20 Dec 2003 20:06:22 -0600
To: Flyrotary List <flyrotary@lancaironline.net>
Message
Greetings,
 
OK, I have my dunce cap on, since I ignored the previous intake lectures. 
 
Say you have TB that has two butterflies, and each butterfly feeds one rotor (primary and secondary).  There is no connection between the two rotors.  Is the length of the intake runner important for full throttle operations?  
 
I assume it is, and recall that racing manifolds can have a short, almost non-existent runner.  I believe Ed used one of these originally, and got less than exceptional performance.  If I recall correctly, it was decided that it would have been fine at racing RPM, but not 5500 or so, where he wanted to run. 
 
Assuming it's important, is there a rule of thumb for the length of the runner for a particular rpm range?  I'm wondering if I can keep my TB in the (turbo free) left cheek, and get enough runner length to optimize operation at about 7500 rpm.  Probably a silly idea, but my only other option is still trying to sneak it under the cowl to the right cheek.
 
Thanks,
Rusty (I can already hear Ed screaming <g>)
      
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