Intake Design Exploration

[vex]

I'm surprised... No critiques or suggestions on improvement? Is my math right? Do the results look accurate?

What runner diameter should I consider accurate? I've been leaning towards 3 to 4 cm in diameter, but if I wish to tune for 3500-5000RPM in peak torque I may run into problems actually fitting the amount of pipe for the runners.

I'll be fooling around with the code (different temperatures, narrowing down the diameter to use, etc) and see if I can't get a finalized result for everyone's benefit. This should be quite helpful for individuals (and vendors) who wish to design their own intake systems.

Consequently here's my next round of questions with regard to runners:
What are the benefits/drawbacks of having multiple diameter runners--Having primaries one diameter and secondaries another? What about tapering? Venturi/Velocity Stacks and their affect on pressure drops, and other flow conditions?

This should prove fairly interesting and thanks everyone for their help and support in this thread thus far! Hopefully others are learning as much as I am!