Does anyone have any sources of info for using a turbo to blow through an SU carb? I’m mostly concerned with controlling or matching the pressure in the float chamber. Some sources suggest equalizing the pressure boost with the float chamber. Others say the boost should control fuel pressure. I once saw an article about someone using an HS or HF type with a low pressure boost in his MG but not sure where that was.
The obvious source might be to contact SU (Burlen FS) directly but I want to get more familiar with this before I ask them.
Art
Without having an answer for your fascinating question, are the issues along the line of,
1.) with no air flowing in carb venturi, atmospheric pressure in float chamber and venturi maintain fuel level without flow,
2.) with air flowing in carb venturi, atmospheric pressure in float chamber is greater than air pressure in air flowing in venturi, float chamber atmosphere pushes fuel into carb airstream since it is higher pressure than carb airstream at jet,
3.) fuel should be pushed into carb airstream to mix at useful air/fuel ratio for engine,
4.) if using turbo to blow air into engine at higher pressures and speeds, then atmospheric pressure on float chamber may not give air/fuel mixture needs at given boost?
Seems complicated for pressure, jet, carb opening, and engine breathing combination. I’m curious to learn what experience has taught others. And would consider using air/fuel mixture exhaust probe when trying things out to keep the engine in healthy condition. My initial guess, and it is only a guess, is that either equalization method you mention would get the engine running in boosted mode but would only be a starting point and other factors would be needed to tune it up to run well.
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Thanks. This is probably the article I saw in the past. Taken step by step it answers a lot of questions I had. I planned to use either an H type or HD type if I can but I do recognize a few things that may need consideration. The cast aluminum air plenum Jaguar uses to link with the air cleaner looks like a great help for this.
Art