SonexB - Cowling Side Vents Required?

[JFYrineo]

There are a couple of Sonex builders in our local area. There was a question about the need for both the exhaust tunnels AND the side cowl vents in the lower cowling. One of our builders reached out to Sonex (after he had installed the side cowl vents) to ask if BOTH were needed (side and exhaust) since this appears to be the documented solution.

The response back from Sonex related to the B Model Cowl with a Jabiru 3300 GEN4 was that the “exhaust tunnels are still needed but the installation of the side vents is too much and not recommended in conjunction with the exhaust tunnels”.

While a couple of our builders have already installed the side vents I’m not at that stage yet and wanted to know if there are other Sonex B model builders out there with some practical experiences they can share (side cowl vents installed or not?)