Answer to Question #63156 in Molecular Physics | Thermodynamics for Marco

Question

Hello,
I have a carburetor, and I would like to re-jet it depending on air density changes, which I am able to calculate correctly from pressure, temperature and relative humidity data.

Now comes the doubt, and hence the question: if, to make an example, the air density increases by 10%, should I change the section of the jets to allow 10% more of flow (i.e. increase the diameter by the square root of 1.10, so go from e.g. a main jet with 1.50mm of diameter to one of 1.57) or the carburetor partly self-compensates for the air density changes, and the correction ratio should thus be lower, and not directly proportional to the ratio of the 2 air densities?

It all comes down to the Venturi effect, but I'm not a physicist hence I'm asking your help.

Thank you very much for your help.
Marco