flyrotary@lancaironline.net Mailing List Archive

In a message dated 5/12/2007 12:43:50 PM Pacific Standard Time, Lehanover@aol.com writes:

Perhaps a .020" hole in both ends of the gage line. You have it sitting on a resonant at idle and the gage will go away after just a bit. Like putting a fuel pressure gage too close to the outlet of a sliding vane fuel pump. It just shakes to pieces.

With the good breathing required for good power, there will be no manifold pressure (vacuum) until the RPM is close to cruise, And then only if cruise is at a bit less than wide open throttle. Maybe the air filter will provide enough drag to get a reading. In fuel injected systems, the lack of a choke, or venturi just adds to the problem.

Lynn E. Hanover

The solution Lynn is the hot wire mass flow sensor. I'm not sure if Tracy could incorporate one in place of the map sensor. The circuitry may be more complicated. There are comercial versions available fro use with many of the throttle bodies. A single P-port inlet tube without an air box poses a real problem. Some of the older mechanical systems are easier to work with on single tube openings. Many of the bikes used an alpha-n system measuring only throttle opening RPM and had a sensor for speed, usually at the rear sprocket. The needed injector map was VERY complex and hard to modify. True mass flow would be better. I wonder what the LeMans 26B used?

Bill Jepson

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