I had a thought I want some opinions on. This relates to matching diameters again.

My assumption is that the whole philosophy of matching pipe diameters (or increasing sizing from front to back) is grounded on the idea that a test pipe is being used. Since a HFC, or cat has a core built into it, would having a increased diameter of the cat, somehow balance out the fact that that section of the piping has a core (less flow) in it?

I hope that question made sense.

Because the core/filter is in there, it would be difficult to not factor it into the calculations of proper diameter is in terms of flow, resonance, backpressure.

This is food for thought. I want to hear your opinions about this!

 

The problem comes from the vacuum effect, and not necessary total airflow.

 

I'm getting in over my head with physics now, but wouldn't the vacuum effect and total air flow be affected by there being a dense honeycomb shaped filter in the middle of the series exhaust pipes.

 

I have the AP2 Comptech Exhaust (http://www.ct-engineering.com/Produc...4/Default.aspx).

Does anyone know whether the ID is 63mm or 70mm?

 

there you go