July 11, 2012
Is that a Helmholtz resonator on your header or are you just happy to see me?
I read some fantastical theories about the function of those funny protuberances growing out of the Red Bull headers in Valencia and Silverstone. The most fantastical is that it is a pressure storage which on the off throttle then dumps gasses into the diffuser, a sort of "analog" hot blown diffuser.
Well, it does not take a genius to imagine the volume of gasses needed to crate that effect does not jibe with what that pipe could possibly contain.
The answer may be have to do with aerodynamics but in a roundabout way. With engines "frozen" in Formula One, one of the battle lines between manufactures are headers whose design in up to the individual teams. Design of the headers is dictated by packaging and can have a significant impact on engine output.
Red Bull designed some very small tight headers to fit in their new very compact rear end but this resulted in a significant power loss.
Renault made some suggestions and Red Bull came back with this solution which using the Helmholtz effect allows the exhaust to maintain the correct resonance for the intake and exhaust pressure waves to be in sync and thus allow more air into the combustion chamber. That involves the Kedenacy effect.
Remember for your next dinner party, 2012 is the year of the effects, Coanda, Helmholtz and Kedenacy, who said Formula One is not educational!