I tried the Great planes version on my G62 that is fitted to a Vailly 90" Seafury. With it fitted I was losing 300rpm on the ground.

Mind you the stack does not extend right out into the airflow, only the tip sticks out past. I did try it with cowl off but saw no improvement.

I'm after an increase in RPM with this excercise.

Wondering how the Zenoah air funnel might help? Any ideas?

What length is the B& B air funnel and where can I get one?

ta
cheers
Peter