|
 Porting
is
basically
opening
up,
re-configuring
and
re-surfacing
the
ports of
a
cylinder
head.
Why port
a
cylinder
head?
The
simple
answer
is to
let the
engine
breath
easier
and more
efficiently
and
therefore
produce
more
power.
Cylinder
head
ports
fall
into two
basic
designs;
the
Straight
Shot
port and
the
High
Approach
port. In
a
Straight
Shot
port,
the
design
allows
for a
line of
sight
from the
inlet
directly
to the
front
opening
of the
intake
valve.
Sometimes
this
design
gives a
lower
flow
value
but
because
it is
straight,
we
attain
higher
velocity
of
fuel/air
entering
chamber.
It also
creates
a
turbulent
spin or
swirling
in the
combustion
chamber,
yielding
a more
efficient
and more
complete
burn.
A High
Approach
port is
where a
turn is
necessary
in the
port
design.
The term
"high
approach"
comes
from
angle of
the last
section
of the
port
relative
to the
valve -
it is
more
in-line
with the
valve
stem.
We take
advantage
of this
to get a
full
volume
flow
path in
the
complete
360°
circumference
of the
valve.
Making a
turn to
an
airflow
is
problematic
but we
caress
the turn
- making
it as
moderate
and
efficient
as
possible
- to use
it in
our
favor.
The
straight
shot
into the
opening
yields a
fuller,
more
uniform
flow
around
the
entire
valve
curtain.
The
advantage
is that
the
complete
valve
opening
is used
more
completely.
Which
approach
we take
is based
on the
original
design
of the
head.
For
example,
the
1986-1990
GSXR
head
uses a
Straight
Shot
port
while
the
1991-1992
GSXR
head
tends
toward a
High
Approach
port.
The
Hayabusa
head
allows
us to
use
parts of
both for
the
ultimate
hybrid
design.
 Our
Cylinder
Head
Porting
Methodology
We take
a very
serious
and
methodical
approach
to
cylinder
head
porting.
The
first
step is
to use
the
traditional
method
of hand
porting
using
grinding
tools
and our
past
experience
and
knowledge
for
shape
and
sizing.
The port
is them
run
through
preliminary
tests on
a flow
bench.
 Once
a design
looks
good, we
copy it
to all
four
cylinders
and then
go to
the
dynamometer
for the
real
test.
While
the flow
bench
gives a
good
indication
of how a
port
will
work,
the
truth in
is the
dyno as
it more
accurately
simulates
re-world
conditions
and
loads
the
engine.
We
sometimes
make as
many a
30 pulls
on a
dyno to
work in
a
design.
After a
few
pulls
the
engine
is
removed,
the head
disassembled
and
ports
re-ground
to wring
out
every
bit of
power we
can get.
It is a
painstaking
approach
but we
feel it
is the
absolute
best way
to do
it.
The
final
design
is
digitized
utilizing
a
Renishaw
Probe on
our
5-axis
Haas CNC
machine.
This
allows
us to
trace
our
absolute
best
design
and
reproduce
it
exactly
for each
cylinder.
One of
the
benefits
of CNC
porting
is that
each
cylinder
is an
exact
duplicate.
If one
cylinder
is down
on power
we know
it is
not the
porting
and that
takes a
variable
out of
the
equation.
The
result
is
maximum
power,
consistency
and
reliability
at a
affordable
price.
Why take
chances?
Carpenter
Race
Engines
offers
the
absolute
finest
in 4
cylinder
big bore
porting. |
