How to Tune an Edelbrock Carb
Edelbrock has been manufacturing aftermarket performance parts since 1933. Primarily known for carburetors and suspension components, the Edelbrock brand is geared toward high-performance parts, having started their business producing components for racing cars. As a result, Edelbrock carburetors can produce large horsepower gains if properly tuned.
Other People Are Reading
Instructions
-
-
1
Park the car on a flat, level surface. Start the engine and allow it to idle for five to ten minutes. It's important for the oil and other fluids to reach normal operating temperature, in order to provide an accurate baseline to tune the carburetors. Once the engine is up to normal operating temperature, turn it off.
-
2
Lift the hood and loosen the wing nut on the air filter cover. Use a rag to protect your fingers if the nut has been warmed by the hot engine. Unclip the wire prongs securing the edges of the air filter and lift it off the engine, revealing the valves.
-
-
3
Connect the rubber hoses from the vacuum gauge to the ports on the intake manifold. This is the pipe connecting the carburetors to the rest of the engine. The small measuring ports on its sides will be plugged with small rubber stoppers. Connecting the gauge to these ports will show the rate at which air is being drawn in to the carburetor. Each dial on the gauge represents the pressure of a different carburetor.
-
4
Start the engine. The brass screw on the front of the carburetor adjusts the idle mixture. Turning the screw counterclockwise will make the mixture leaner, reducing the amount of fuel in the mixture. Turn it counterclockwise until the engine struggles to idle, then increase it slightly until the engine runs smoothly again. The idea is to have the idle mixture be as lean as possible without stalling.
-
5
Have your assistant press the accelerator pedal, revving the engine close to, but not over, the red zone on the tachometer. The vacuum gauges should stay largely constant during this. If they spike, and the engine appears to be about to stall, there is insufficient fuel entering the carburetor. If the vacuum gauges dip, the mixture is too rich and needs more air.
-
6
Adjust the screw on the side of the carburetor to alter the metering jets, adding more or less air to the fuel mixture when under power. Repeat the test with the vacuum gauge until the needle stays steady when revving the engine. When it does, remove the gauge, replace the air filter cover and wing nut and lower the hood.
-
1
References
Resources
- Photo Credit engine image by pearlguy from Fotolia.com
