# Howto calculate ITB runner length and velocity stack shape/length.



## ScareMercy (Oct 31, 2010)

Hello,

Today I finally bought my 46mm ITB's for my 2.1 liter 16V. I would like to make the manifold and velocity stacks myself, but can't seem to find the right information for the calculations involved. Could someone enlighten me with some information and/or formula's? 

I have acces to some simulation software, some 3- and 4-axis cnc machine's and a 3D printer to make some sample's for testing.


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## Smoothwaterman (Feb 17, 2014)

This is for a 2.0, but it may help. 

http://forums.vwvortex.com/showthre...Excel-sheet-for-Intake-manifold-runner-length.


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