There is no way to get true numbers with flow tests of any type.
Be it on a air flow bench to measure CFMs ,air speed, air direction,
with the use of air,or air with dies,smoke as a marker for measurement.
To use as a judgement tool.
I have read about a flow bench being built buy a shop owner to flow
test A complete long block. Less crank, rods, pistons.With the block
having the bottom of block cut off .From the bottom of the cylinders
to oil pan rail.And make claims that this is the closest one could get
to real world flow numbers.The guy used a degree wheel on the cam
and to turn the valvetrain,& Dial indicator to read valve lift.
Air speed measurement was mentioned. I believe the name for the
tool to read air speed is a manometer.It is basicaly a fan blades with speedometer held or placed in the airs path.You can purchase hand
held meters or mount to flowbench.
It was mentioned about tapers in manifold and runners.If you cut a
SC Bird manifold in half. You can see the manifold tapers down toward
the intake port entrance. I think this not to be to bad of shape for
an open blower manifold ,that fits under the hood. I think we would
have a jump in air flow performance. If we could flip the manifold over
And raise the heads intake ports floors runners.
It would be to much work to mod a stock manifold. But it would be
nice to try and cut out the top and bottom of are manifold out.
Flip the peice over and weld back in. This would help with air flow,
by raising it up to go down into the intake port.Instead of the almost
S curve the stock air path has to travel. And the manifold would still
be tapered toward the intake port to increase air speed with volume.
This post is making me to want to be able to go to the shop and work.
And kick myself for selling my flow bench a few years ago.But it was
small,old,and collecting dust.
Randy