I am not familiar with the BCM433. If you mean BCM43341/BCM43340, I'm not sure as the application support within the WICED SDK is fairly limited for this device (HCI layer access only, no stack).
However, on the BLE only side represented here with the BCM2073X series of products: WICED Smart Bluetooth Forums
There is a speed_test application in the WICED Smart SDK which by default allows 7.5ms connection intervals.
Many thanks for the hint,
I'll look on a speed_test application.