On modern racecars, shocks run at very
low main piston speeds. In addition, they
are forced to have very little travel in
order to keep the car's aerodynamic
changes to a minimum. The result of this
short stroke is only a small volume of oil
is displaced during the stroke cycle. A
shock absorber is a dynamic device. It
only works when it is moving. As a result,
the most important characteristic of a
racing shock is precise control over this
small volume of oil moving at low speed.
Most racing shock designs utilize a
relatively small diameter piston rod and a
needle valve for controlling oil flow.
ProTrac uses a large piston rod in order
to deliver maximum fluid displacement at
small suspension travels.
Although the needle valve is a simple
and effective mechanism, it has it's
problems. The major disadvantage of
this system is extreme sensitivity to
manufacturing tolerances, temperature
variations (oil viscosity) and it is VERY
easily damaged. Any of these can cause
varia tion in damping force between
shocks as well as making adjustments
ineffective. Regular performance checks
are necessary on needle valve shocks to
ensure properly matched sets. You can
wind up spending more time on the
shock dyno than on the track.
Because the large piston rod displaces a
large amount of oil, ProTrac's rebound
and compression mechanisms work
more efficiently.
ProTrac believes that accuracy, consistency and repeatability are the
Most important design requirements.
Therefore, ProTrac has designed an
advanced and very accurate adjustment
mechanism for rebound and
compression control.
Instead of needle valves, ProTrac uses
porting for rebound adjustment.
Performance depends on the precision
of the ports. ProTrac's ports that have
been very precisely drilled on a CNC
milling machine to ensure that their
position and diameter are within the very
fine tolerances necessary for total
repeat-ability. The accuracy and
repeatability of CNC-milling also assures
that all shocks in a set have exactly the
same charac-teristics.
On the compression side, ProTrac loads
the blow-off valve wit h Belleville springs
because of their proven accuracy and
ProTrac B.V.
Rietdekkerstraat 3
5405 AX UDEN
The Netherlands
Phone+31 (0)413 - 259 100
Fax+31 (0)413 - 259 770
Internetwww.protrac.nl
[email protected]
consistency. The blow-off valve is
matched to the large oil displacement
caused by the large piston rod diameter
and responds to the smallest movement
of the suspension. The system can be
precisely tuned to your specifications
and requirements.
Another advantage to ProTrac shocks is
the use of the gas pressure in the remote
reservoir as an adjustable medium. In
combination with the large oil displacement, the gas pressure assists in
supporting the chassis without increasing
the spring rate.
This feature of ProTrac shocks allows
the suspension engineer to use gas
pressure as a setup instrument and
saves valuable track time.
The ProTrac shock is built as a modular
shock, so all of our shocks share the
same high performance features and
the
shock lengths and damping
characteristics can be modified
according to your individual needs and
specifications. Because ProTrac uses
long-life seals and shock oil especially
developed for endurance racing, our
shocks require very little maintenance.
ProTrac's goal is to satisfy our
customers by optimizing the handling
characteristics of their racecars by
manufacturing high quality shocks
and delivering outstanding service.
Our services include:
Every ProTrac customer receives a dyno
report detailing your shocks' characteristics throughout their adjustment
range. This is true both for new shocks
and for those you send to us for
refreshing or repair. The shock dyno is
one of several tools we use for
diagnosing problems and performance
inconsistencies in your shocks. We
maintain a complete file on all of your
shock absorbers and enclose an easily
filled-out ProTrac Shock Absorber Log
Sheet with every shock absorber to help
us track, diagnose and improve your
performance.
We recommend an inspection and
freshening after each racing season to
maintain optimum performance and to
provide preventative maintenance.
ProTrac's shock overhaul package
includes a complete oil change and
replacement of all o-rings and seals,
followed by a session on the dyno. Yes,
you will get a copy of the dyno sheet.
If and when you want to modify your
shocks to more exactly match performance curves to certain tracks or certain
applications, we will be happy to discuss
adaptations to meet your requirements.
ProTrac also offers the services of our
suspension engineers trackside to
advise, support and service your shocks
anywhere in the world. After each test
session, you will receive a detailed report
of the set-up, shock curves and testing
results.
ProTrac B.V.
Rietdekkerstraat 3
5405 AX UDEN
The Netherlands
Phone+31 (0)413 - 259 100
Fax+31 (0)413 - 259 770
Internetwww.protrac.nl
[email protected]
ProTrac is structured to enable us to
offer custom design and manufacturing
services to our customers. If you have a
special application, we can provide you
with custom designs reflecting the
leading edge of racing shock
engineering. We will work closely with
you from the initial sketches to the final
manufacturing and assembly of your
shocks. A ProTrac engineer will
accompany you for track testing of all
custom designs to ensure they meet
your requirements.