As every Drag Racer knows, consistency wins championships.
John Calvert has achieved championship status in the highly competitive
field of NHRA drag racing. He has 20 plus years of racing experience over
every type of track condition imaginable. John has won most of his races in
a 1968 Ford 428 cu/in powered Cobra Jet Mustang. He knows the idiosyncrasies
and potentials of his car without question; He knows the importance of
understanding and fine tuning all the components needed for repeated
successful performance. His experience and success over the years with his
car provide him with an excellent base line from which to create more
efficient modifications. It has in this experimental role that John and his
skilled friend Larry Kieser developed the CALTRACS traction enhancement
In Stock Class, where John's major racing endeavor has been
shaped, NHRA dictates that a maximum of 9" slicks can be used. This presents
a racing dilemma to a driver when trying to couple big block power to the
ground. The CALTRACS design was developed in John's garage. Brainstorming
together, Larry and John created the design and the first model of the
system. CALTRACS augments the car and driver potential to specific
performance goals while complying with hard set NHRA class parameters.
John's concept won the enthusiastic approval of his family.
Two brothers, Keith and Paul and Dad, Bernerd all share a talent and
fascination for the world of mechanical engineering. Combined they hold over
75 years of career involvement in Aerospace engineering and production.
CALTRACS has been distributed to Europe for serious
competitors there. If you travel to Sweden, there's a good chance you would
see a set of CALTRACS in action.
Tremendous benefits can be realized when the CALTRACS
traction bar system is installed on a leaf spring suspended automobile.
CALTRACS traction bars were developed to achieve specific goals to improve
high power traction while staying within hard set NHRA parameters.
Each of the two assemblies needed is comprised of three
Force Transfer Link
The combination of these components changes the pushing
point on the car by redirecting the turning action (spring wrap-up) of the
rear axle through the Force Transfer Link into the Front Pivot. The Front
Pivot Spring Stop Bolt resists this turning motion and also controls the
bending of the leaf spring at its thinnest section. The push into the Front
Pivot helps the cars weight shift towards the rear of the car because of a
new directed angle of force toward the front of the vehicle. (The "Instant
Center" moves farther forward). This is where the system emulates a Four
link system. The pinion angle is also maintained. (See illustration)
1. The Front Pivot
Two steel plates sandwich the leaf spring sides. Two attach
points in the plates provide the user with a selection in which the forward
Force Transfer Link rod end can be located. A machined aluminum spring eye
bushing and steel insert supports the front of the spring while allowing the
plates to pivot. A spring stop bolt controls and restricts spring wrap-up.
Spacers are provided for different vehicle applications that control
clearances in the front spring eye pocket.
|2. Force Transfer Link
This is a length of chromolly tubing with CNC machined threaded
inserts TIG welded into each end. The front Insert is machined with
right hand Threads and a HEX outer shape for Simple wrench
adjustment of the Installed assembly. The rear insert is Left hand
threaded. Opposite thread Styles at each end provide the means to
easily lengthen or shorten the link for desired pre-load adjustment.
3. Rear Mount
A welded ¼" steel assembly replaces the original vehicles
spring perch and incorporates the mounting provisions for the rear rod end
of the Force Transfer Link.
Installing the CALTRACS is very straightforward. Raise and
support the car high enough to remove the rear tires. Allow adequate working
space. Next, the rear spring assemblies should be removed. This will
facilitate replacement of the front eye bushings. Support the rear end
housing in place while the springs are out. This will eliminate the need to
disconnect the drive shaft, brake lines etc. Press or have pressed, the
original front eye bushing out of each spring assembly. Replace these with
the machined aluminum CALTRACS bushings supplied in the kit. Now, reinstall
the rear springs into the car.
With each spring assembly ready to go in, position the
forward pivot assembly to the front spring eye. (Assure that the Spring Stop
Bolt is located on the upper surface of the spring.) Install the Steel
Bushing through the pivot and front spring eye bushing. Now, reinstall the
spring using the original hardware. Repeat the process for the other side.
Lower the rear axle assembly on to the springs. Install the
supplied spring perches as you would the stock items being replaced. Attach
Now the Force Transfer Link can be installed by starting the
HEX (wrenching) end on to the forward rod end. Remove the rear rod end from
the spring perch and start its threads into the rear Force Transfer Link.
Adjust the assembly to proper length by holding the rear rod end then
rotating the Force Transfer Link until the rear rod end will line up with
the mounting hole in the rear spring perch. Install the rear rod end
fastener and secure.
With the CALTRACS installed and the rear tires reinstalled,
lower the car to the ground. As an initial setting, turn the Force Transfer
Link until the spring Stop Bolt just contacts the upper surface of the
spring, then turn the Force Transfer Link one turn more to establish
pre-load. Tighten the Force Transfer Link lock nut. That's it!
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