j-dub wrote:
So Brian,
I know you have done a lot of thinking about manifold length with respect to tuning pulse tuning. A typical IDF/DRLA manifold length is 7 inches, similar for IDA manifolds. The short IDA manifolds I have are 5.5 inches, I assume yours are similar.
So when you were working on your pules tuning were you focused on you intake valve to venturi length or intake valve to velocity stack length?
Thanks,
Jeremy
The major wave reflection is off the opening of the velocity stacks to the atmosphere. So I used the length form the back of the intake valves to the opening on the velocity stacks, along the centerline of the path. I run Berg short IDA manifolds with about 5/8" of spacer (1/2 custom aluminum spacers + 1/8" poly spacers/isolators) to get the length I wanted based on the expected RPM range I designed the motor for. I've got a harmonic right around 7500 RPM that gives it a little "boost" right there and helped me get 100 hp per liter. Fun stuff
