Postby MiGhost » Mon Jun 09, 2014 12:48 pm
JC. The air filter looks real good. Very much like the old breadbox style. The only change that I would make would be to use a set of stock airbox boots in place of the pod boots.
It is not so much the airbox style that is the problem using pods with the cv carbs. The big problem is how the airflow enters the carb.
As Mainerider pointed out. It is the turbulance that is created that causes the problems.
The pods have a sharp turn into the carb into the boot, and very short throat length. This creates turbulance in the airflow right at the front of the carb opening where the air jets are. This causes the problem of the jets not getting the proper air supply. Which in turn creates the lean mixture condition.
With the stock airbox boots. The bell mouth design smooths out and, moves this turbulance away from the air jets to allow the airflow to be directed into the air jets for the proper mixtures.
If you look at it like this. You will understand it better.
Airflow can not turn at an angle. It will always try to go straight.
The vacuum created when the valves open, and the air/fuel mixture charge is drawn into the cylinder creates a pulse that travels back through the carb to pull more air in.
With the pods. This creates a rolling action to the airflow.
The airflow can not make the sharp turn, but the vacuum pulse pulls the airflow on a curve into the boot. This curved flow pattern creates a low presure (vacuum) area underneath it that the airflow spins back into, and slows down. When the airflow comes back in contact with the incoming air. It once again has to change direction, and speed up. This creates tiny vortexes (vortices') of swirling, spinning air (turbulance) that travel through the boot to the front of the carb.
When these vortices' reach the area of the air jets. They are moving in a direction across the top of the air jets. Not straight into the opening of the jet. This creates yet another tiny low pressure area right at the opening of the air jet. The short length of the boot does not allow the time needed for the airflow to straighten, and smooth out.
With the stock airbox boots.
The bell mouth (velocity stack) shape of the opening reduces the amount of low pressure area that can develop. This allows the vacuum pulse to straighten out the airflow quicker, and move it faster through the boot. As the airflow is not having to deal with the spinning turbulance. It travels straight into the air jet opening. Which is what you need for proper fuel jet operation.
Have you ever noticed how high performace engines running without an air filter almost always use a long bell shaped velocity stack?
To control the airflow, and limit the turbulance is why.
Sorry about the long winded, overly simplified, highly untechnical expalination.
Hope it helps to understand the problem with pods.
Ghost