Tom
Austin
<
TAustin@
sierraresearch.
com>
Transmission
Date:
01/
28/
2005
02:
34:
41
PM
To:
Alan
Stout/
AA/
USEPA/
US@
EPA
cc:
"
Pamela
Amette
(
E­
mail)"
<
pamette@
mic.
org>
Subject:
ATV
Engine
Power
Hello
Alan:

As
you
requested
during
our
recent
conference
call,
I
am
providing
a
table
showing
the
rated
speeds
for
the
ATV
engines
involved
in
the
test
procedure
development
program
running
at
SwRI
(
see
attached
file
ATV_
Rated_
Vac.
doc).
My
recollection
was
pretty
close;
all
but
one
of
the
engines
has
a
rated
speed
in
the
range
of
6500
to
7000
rpm.
One
engine
is
rated
at
5250
rpm.
Note
also
that
the
table
shows
the
approximate
manifold
vacuum
(
in
inches
of
mercury)
for
each
engine
at
idle,
wide
open
throttle
(
i.
e.,
"
min"),
and
closed
throttle
decel
(
i.
e.,
"
max").

I've
also
attached
an
Excel
file
showing
the
distribution
of
engine
speed
and
load
during
field
testing
and
during
the
chassis
dynamometer
testing.
During
the
field
testing,
only
1%
of
the
time
was
spent
at
loads
in
excess
of
50%
of
full
load.
As
you
will
be
able
to
see,
the
most
frequent
operating
modes
were
in
the
range
of
0
to
35%
of
full
load.

As
the
distribution
for
the
chassis
dynamometer
testing
shows,
less
than
0.1%
of
the
time
was
spent
at
loads
in
excess
of
50%
of
full
load.
The
most
frequent
operating
modes
were
in
the
range
of
0
to
25%
of
full
load.
As
I
mentioned
during
our
telephone
conversation,
the
maximum
percent
of
rated
power
for
any
single
vehicle
was
52%
under
these
test
conditions.
That
is
the
basis
for
MIC's
request
to
adjust
the
30
kW
threshold
to
60
kW
if
the
definition
of
maximum
engine
power
is
changed
to
manufacturers
rated
power
or
maximum
power
at
rated
speed.

I
know
there
is
concern
about
opening
up
the
ATV
category
to
too
many
more
engines;
however,
the
ORUV
definition
only
applies
to
vehicles
designed
for
use
over
"
rough
terrain."

Let
me
know
if
you
have
any
questions
regarding
the
attachments
or
this
email.

Regards,
Tom
Austin
Rated
Speeds
and
Typical
Vacuum
Readings
During
Idle
and
Aggressive
Riding
rpm/
inches
of
Mercury
vacuum
Rated
Speed
Idle
Min
Max
Polaris
Sportsman
500
6500
11
0.5
21
Polaris
Ranger
5250
12
1.3
22
Honda
Rubicon
6500
8.5
0.2
17
Honda
Rancher
6500
10
0.0
19
Honda
Sportstrax
7000
11
0.2
20
Kawasaki
Prairie
6500
9
0.6
19
Kawasaki
Bayou
250
7000
10
0.0
18
Yamaha
Big
Bear
400
6500
10
0.8
20
Yamaha
Raptor
660
6500
8
0.7
18
Suzuki
QuadSport
7000
12
0.6
21
