Dale Rogers wrote:

Jim,

  I think you skimmed over an important qualification of Dave's comment:  

... The worry to me here is that with the
TB at the other end of the runner,ie close to the port,      

which exactly fills this part of your analysis: Really?  Are his injectors UPstream from the throttle body?  That's what I said caused carb ice.  I understood him to say that his injectors were near (but DOWNstream from) his throttle body.

.. I think carb ice is pretty much always associated with fuel sprayed into a venturi, and the injectors in our application are always downstream of the "venturi" formed by the partially open throttle.
   

Dale R.
(the world needs more Lerts ...)

 

From: Jim Sower <canarder@frontiernet.net>
Date: 2005/06/20 Mon PM 09:18:54 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Fuel Injector Position (was  Re:
Makingprogress on Chris n Dave's Velocity Engine)

But wouldn't that be true of ANY injectors placed a significant distance from the block?  I think carb ice is pretty much always associated with fuel sprayed into a venturi, and the injectors in our application are always downstream of the "venturi" formed by the partially open throttle.
I wouldn't worry ... Jim S.

david mccandless wrote:

   

   On PL's recent PP dyno run, he stated that with the injectors
   placed near the entry of the runners, there was considerable
   evaporative cooling taking place and as the tubes were running
   very cold VE should be good. The worry to me here is that with the
   TB at the other end of the runner,ie close to the port, there is a
   real risk of ice build up on the throttle body butterfly. The old
   bugbear of carb ice is back. FWIW, Dave McC


   since the

       ----- Original Message ----- *From:* Jerry Hey
               based on Paul Lamar's current p port testing there is no
       problem with placing the injectors at the far end of the
       runners. This is also backed up by an article on the internet
       (How to Fabricate an Intake Manifold) The idle issue is not
       with injector location but rather with butterfly location.