plenum volume

[Bruce Plecan]

  Not sure if this is the right form, but it has to do with my crossfire injected project. It seems that a better(more even) distribution and better flow would result from moving the top plate/swirl plates away from the manifold floor.

  True

   This would also change the plenum volume.

  True

   What part does plenum volume play in the over all scheme of intake design?

  Lots, it basically controls what rpm the engine makes peak torque/HP.  Also, makes up for flow limits in TB (to a minor degree).

   How will increasing it effect performance, and is there a formula for figuring the correct volume for a certain engine combination?

  Varies alot.  Anything from one cylinders volume, to 1.5+x the engine's CID.

   I would like to base the changes on something other than physical restraints(hood clearance etc.), without having to try a bunch of different combos with all the tuning and testing etc involved.

  I have sone extensive porting mods to the cross fire manifold.  Making a 1/4" thick spacer for the lid made a large difference (BTW, I'm running a 355 CID).  Much better high rpm breathing.
  Also, ground out the ERG tunnel.  Opened up the outside pockets, and cut port roofs back 1/8" also.   With enough cam 2" butterflies also help.
     BTW run it with a 1227747.  I some wotk but with the info from programming 101 makes it real sweet.
  Grumpy

  Kevin R
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