The exhaust does not hit one blade at a time, so the waves generated are not so prominent. Moreover, for there to be a significant pressure differential across the turbine, the speed of the gas relative to the tips is just a bit below Mach 1, so little, if any, of the fluctuations will travel back up-stream.Horsewidower wrote:My point, in raw layman's terms, is that you have a turbine spinning at 80.000+ rpm which creates its own set of waves. That set of waves will, and I'm making an assumption, wreak havoc with the wave tuning solutions that exist for NA applications.
Horsewidower wrote: I agree with the idea, however, that there may be an advantage to header design that makes use of a pulse methodology.
In most turbo applications, it's more important just to make them short, high flowing, and equal-length. Remember that turbo exhaust gas temperature is MUCH higher, and so thus is the local speed of the exhaust pulses. That means that the header tuned length must either be MUCH longer, or tuned for the second reversion wave (which is no easy task to accomplish). Sometimes, even getting them equal length is asking more effort than is really practical, and it's easier to achieve similar gains by separating adjacently-firing cylinders to remove residual back-pressure interference.
As mentioned, it's not turbo back-pressure which makes it tough: it's the temperature. Typical turbo tuning length would have to be about THREE FEET. Talk about laggy, eh?Horsewidower wrote:The only time that an NA type wave tuning solution might be applicable would be in a wastegate priority system wherein a majority of the exhaust is being "wasted" after the engine reaches a preset psi. I.E. the former Cosworth CART engines.
-Adrian