Originally Posted by Oneiros
Hrm that's really useful info.. anyone have measurements on the stock port runners / manifold save me pulling mine apart?
Btw how did you get that equation? Also wouldn't it be affected by the ID of the intake, whether you have a 2 or 4 barrel carb, etc..
Am very curious about this as I'd like to make some effective stacks for a nikki, with longer stacks on the primaries and shorter on secondaries. Cheers
That information is from an article popular hot-rodding did on "ram tuning" which is basically optimizing the intake length to take advantage of pressure waves that travel back and forth for a natural supercharging effect.
They dyno'd a car back to back with nothing but velocity stack changes and noticed how the blip in the torque graph moved. The equations are from Chrysler's lab notes on the very subject when they got serious about the subject back sometime in like the 70's.
As for your question, runner diameter will effect the powerband, but changes to the length will have their own effect, separate from the runner diameter. However a radially cammed engine (and with larger diameter runners) would probably benefit from doing their calculations with the 80,000 figure as opposed to the 84000 as stated.