[s-cars] Re: [S-Car]Ain't no small intercooler here

[QSHIPQ at aol.com]

--
[ Picked text/plain from multipart/alternative ]
Mike:
The "rolled" teepee design (the left one) can be seen on Audisports own IC's.
 The object here is to reduce the turbulence inside the endcap, which reduces
both the end caps CAT, plus increases in flow for a given design.  Read:  All
else being equal, you have increased the efficiency of a given IC size.  I'm
only familiar with the rounded design you CAD'd below, the pointed design
theory is fairly new in terms of application/practice.  IMU, the pointed
design is used when the end caps have a straight thru (no bends to inlets,
centered and straight inlets - see mitsu evo rally car IC).  For all other
applications, the rounded design should prove more efficient.

WRT turbos being supersonic, that is the nature of turbocharging.  A turbo
compressor is a convergent-divergent nozzle by definition, (for more on this
try  Swedish engineer de Laval c-d theory).  Here you are really playing in
the area of A/R ratios on the hot side, and wheel/housing design on the cold
side.  It is not uncommon for turbos to "go supersonic" especially at
compressor blade tips.  At a certain point tho, you can cause a vortex at the
inlet, where any increase in speed, only increases heat (and noise rises
eponentially).  As a general rule, a larger A/R ratio will decrease turbo
speed, and a small A/R ratio will increase turbo speed (duh?).  You will also
find that cold side applications make a bigger difference on a specific motor
than hot side applications.

In sizing turbos, you usually see that turbo hot side size is dictated by
displacement, engine VE/IM/PR/DR tuning is done on the cold side.  There are
some really bizarre cold sides (even from KKK) including extra "winds" in the
scroll to increase the lowend torque while maintaining hi end HP, we have
that on the S2 (an expensive MTM derived part), and maximum 26psi boost is
achieved immediately in any gear (read: virtually zero lag).