Hi Guys;

Sent this to the other list a while back.
Attached is a pic a local fellow sent some time ago detailing a
comparison of various intakes.

 

The improvement in air flow is just about a direct connection to HP increase. A 10% improvement = a 10% increase in HP.

 

All you really need to do is keep high velocity airflow away from the edges of the intake tube. Air cannot change direction readily (has mass) and thus impinges on air entering the pipe from along the centerline, that is not changing direction to enter the pipe.

 

So, the tapered part of the horn, need not have a radius at all. It just needs to be at least three times the diameter of the pipe. Could be a rectangle. Need not be round.

 

Also all of this radius stuff still leaves high velocity air in the sonic range just inside the end of the pipe after the horn. So now the improved airflow volume is adding to that problem.

 

Where room permits, the tube could be increasing in diameter several inches before the horn begins, and sonic flow can be moved well down the tube.

 

Another approach could be to use two tubes of larger diameter rather than 4 smaller tubes. I would use a tube diameter so as to keep velocity well below sonic, and reduce the cross section right before the intake ports, so just subsonic flow is there and nowhere else.

 

The 180 just before the ports should be flattened on the inside of the turn, with some small VGs  (triangular chisel pricks) to keep flow attached to the inner wall.

 

That extra 10 HP could be usefull.

 

Lynn E. Hanover