[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]

RE: intake manifold polishing


Bingo, the porting stone pattern trips the boundary layer
into a turbulent layer, allowing larger scale patterns
to develop, the 'swirl'.  It's the tripping of the boundary 
layer to turbulent that allows the increase in air speed.

As an aside, the opposite occurs in boats.  Racers used
to wax the hull to allow water to bead up.  It actually takes
more energy to force the water to bead up than it does to 
allow it to 'wet' out against the hull.  Racers use a smooth,
but not waxed surface now.  They want to encourage a
smooth transition between moving hull and stationary
water, it's more efficient.

Jeff  '67 Sqbk
* * * * * * * * * * * *
Oh boy, finally a topic I can offer my two cents. 
 Polishing the intake manifold, does offer an advantage, over a
non-polished manifold. I'm not sure, if you would see any gains with a
stock engine. Once we port and polished the heads, the manifolds had
become a restriction. And you must match port the manifold with the head
(gasket included). We've also found out that, if the manifold gasket
projects just the slightest amount into the port, flow is reduced. Today
polishing the manifold thinking has changed. We port the manifolds, but
don't polish them, like we used to. The porting stone leaves a fine
pattern, that improves flow by creating a 
swirl pattern in the air. This also increases the air speed. Hopes this
helps you.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]