Several people have asked about this. The SIG eyelets used to make the spigot/"fuel post" in spigot venturi are one of these:

http://sigmfg.com/cgi-bin/dpsmart.exe/IndexBuidlingMaterialsEquipmentF.html?E+Sig

   I think it is the SH-212 (1/32 ID), but the one you want is the one with the 1/16 OD of the barrel. To install in your 1/16" dribble hole venturi, measure the OD of the barrel, make sure it is the right one It should press in with moderate pressure. Measure the OD of the head, pick the next biggest AWG drill size, and *very carefully* counterbore the spraybar side of the hole. I highly recommend a drill press on medium to high speed and a very gentle touch. There is not a lot of extra thickness, so no more than about 1/32" deep.

Then push the eyelet in until it protrudes about .030 from the wall of the venturi. You can count on the press fit to hold it in that position, and you can adjust it slightly by pushing on either end (gently). You can experiment with the protrusion, more protrusion, up to about halfway, might improve the relative fuel draw but anything more than .010 will get most of the useful flow effects. Of course the further you push it in, the less choke area you get for a given venturi bore, but you can make the bore larger to compensate.

     Less than .010, and you start getting either the schneurle effects (faster/hard lean on outsides) again or uneven running from the dribbling or marginal atomization.

      Brett

It's a quite complex interaction and you just made it more complex. Thanks L

   Happy to help!   I think it's probably simpler that it might first seem. The issue for the venturi with the flush inlet appears to be related to the angle of attack of the venturi bore. One way and the fuel just dribbles down the side, and the other way it doesn't. Anything that gets the flow away from the wall of the venturi seems to be sufficient to solve the issue. Below about .010, it just seems to keep dribbling down the side, presumably because it's in/below the boundary layer.

      Some engines have been borderline unusable due to running much different on insides VS outsides. This is probably in addition to any other internal ballistics effects as we had previously discussed.

     And yes, we have seen the dribbling effect, by looking straight down the bore in bench runs, it seems to act like drips from a leaky faucet - builds up slowly, then breaks off, and when it does, the engine takes a momentary "blurp", even when it is otherwise running OK. It definitely proves that there are dead spots or eddies in the intake flow in some circumstances, smooth curve or drilled-out.

Btw, Lost Hills in October 7.-8. Free flight..

   Stick around a few weeks, Madera October 21-22, Golden State Stunt Championships.

    Brett