Edelbrock Carburetor Tuning
 

I had a Holley carburetor on the engine for a long time and it was OK but since I did not drive the car often, the bowl gaskets tended to dry out.  Of course, when I did drive it they leaked.


I’d read a bit about the Edelbrock carburetors and they seemed to be very adjustable and would have fewer leakage issues because the bowl bottoms were solid.


Once the carb was on, I drove it and found that there was a hesitation on light acceleration.  I read the very comprehensive manual and made a few changes (accelerator rod and the springs in the jet rods).  It seemed OK but there was still just a slight hesitation so I decided that I’d try to see if I could make the mixture a bit richer or leaner to fix it.


The Edelbrock documentation provided a graph that was difficult to interpret and did not satisfy my need to determine the best combination of rods and jets to make a small change.  So I created a rodsnjets.xls in Microsoft Excel (and converted to a PDF file - rodsnjets.pdf) to provide an objective measurement of fuel flow by subtracting the rod cross section from the jet cross sectional area for each rod and each jet combination and for the “cruise” and “power” modes.


There are some instructions on how to use this at the bottom of the Data page.  The ShowMath sheet provides the formulas used to generate the data.


It really helped me dial in the mixture by identifying the combinations needed to make small changes to the off-idle mixture, and I’m very happy with the way the car runs now.