I am not an engineer but I can evaluate trends.
One trend in air cooled development seems to be a resistance to change.
For generations we have seen headers for air-cooled 911 engine basically unchanged with the exception of primary diameter and collector design.
My question has always been, why are so many engine builders sticking to a header design that was conceived for a 2.0, 8000rpm engine? Same basic runner lengths regardless of cam configuration, intake lengths and desired RPM range.
We've been experimenting with runner lengths and collector with some good seat of the pant results. The idea of long primary tubes to create "better" low end torque in engines that never run in what I consider to be "low"end rpm range seems ridiculous.
I no longer have a dyno so I can't produce "real" numbers but customers seem happy with the results.
These headers
are not our design and the origin of the design seems to be in question but regardless of the designer, these little guys are showing us a lot of seat of the pants smiles.
