Another Weber Question for you guru's, anyone running a different emulsion tube from f11? Options

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I've been playing with my Weber 40's for a couple years now and am pretty happy with the setup. Then I took it to a local chassis dyno to see how I had done. The engine runs pretty strong for a 1911. However, the torque curve has a good size dip from about 3200 to about 3600 rpm and then takes off and stays pretty flat until the valves float at 5700 rpm. The AFR goes super rich during this dip in the torque curve. We made 5 runs with 4 different jets. The richer jets (135 & 145) enlarge the dip. The leaner jets (125 & 130) do better but I'm still losing about 5 ft-lbs of torque and they go really lean on the top end. I'm not sure if I can get rid of this dip. It may be mostly form the "tune" of the mechanical components of the engine. I'm thinking of trying a different emulsion tube to see if I can lean out the bottom end some. This has been a very educational experience. The engine is pretty tolerant of AFR: anything from 12.0-14.0 seems to run pretty good. When the AFR gets out of these bounds you can see the torque fall off relative to the other runs.

Present settings: 40 idf, 32mm vents, 55 idles, 125 mains, 200 Air correction, f11 emulsion tube.

What I would like to try is a different emulsion tube and then go back and work with the mains and air correction.

Has anyone run anything other than f11's?? Any suggestions for an emulsion tube to get a little leaner bottom end?


OBTW, I've dropped the engine and am dealing with the valve float issue. It's driving me crazy. (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif)