PTS Flowbench Forum

Hey everyone,

I am new on this forum. I am currently working on a Formula SAE car and I am about to begin flowing our cylinder head. I was wondering why is it that some people put putty around the opening to the intake port when flow testing? Is this a necessary step or will this give skewed numbers?

Thanks in advance.

Hello, It is a necessity as it streamlines the air into the port. Without the radius (usually clay) the air will be turbulent going into the port reducing air flow a lot. Us motorcycle guys usually make a ram tube out of aluminum but most of the car guys form a bead of clay. Hope this helps, Jim

You will get skewed numbers if you try flowing a cylinder head with just the bare flat manifold face.
The very sharp edge leading into the port creates turbulent flow, which will be nothing like what happens when there is an intake manifold to guide the flow straight into the port.

There must be a large smooth radius or bell mouth entry leading into the port face.
Many different ways to do that, and they all work.
Clay or putty is fine for a quick test, but if you are going to be doing a lot of repeat flow testing, something made from wood, metal, or plastic will be much more convenient in the long term.

Tony wrote:You will get skewed numbers if you try flowing a cylinder head with just the bare flat manifold face.
The very sharp edge leading into the port creates turbulent flow, which will be nothing like what happens when there is an intake manifold to guide the flow straight into the port.

There must be a large smooth radius or bell mouth entry leading into the port face.
Many different ways to do that, and they all work.
Clay or putty is fine for a quick test, but if you are going to be doing a lot of repeat flow testing, something made from wood, metal, or plastic will be much more convenient in the long term.

And much more repeatable. Take Tony's advice and make a permanent adapter.

John

On my heads the putty tends to lift off en then gets eaten by the flowbench

I flow the head with the manifold on and a rampipe attached now (this manifold is pretty much a given anyway for what i work on and no manifold just does not make too much sense IMHO as then i have to retest if the gains present without the manifold are still there with the manifold on.)