Lessons Learned In Championship PRO Rally Effort Applied To
BY MITCH McCULLOUGH
Drilled pedals, including a massive dead pedal, are
identical to those on the rally car.
The 16x7.5 inch TSW Hockenheim wheels with 205/45 VR16
Yokohama AVS Intermediate tires fill the fender wells.
The Road/Race Mazda 323 GTX for the street is happiest on
pavement, but can quickly be set up for unpaved roads.
Mitch McCullough's Mazda 323 GTX rally car won the 1993
California Rally series and 1994 SCCA Southern Pacific
Divisional PRO Rally championships.
When Mazda introduced the 1988 323 GTX as a "street legal
rally car," it backed its claim with a turbocharged engine,
four wheel drive and a factory-supported rally effort. The
GTX was a blast to drive, but the American masses had
difficulty understanding the benefits of high-performance
four-wheel-drive and even more difficulty justifying prices
ranging from $12,999 to $15,999. After all, the GTX looked
like the 323 commuter car next door. As a result, Mazda
Motor of America dropped the GTX after only one model year
and may have sold fewer than a thousand examples.
In the ensuing years, the GTX was sought after by
rallyists and became a cult car for enthusiasts. Today, it's
still a fast, fun, reliable street car and a great
divisional-level PRO Rally car--if you can find one.
We found two. Each had an odometer around six figures.
One became a championship-winning rally car, the other a
fast, semi-invisible, road warrior.
A stock 323 GTX is equipped with a 132-horsepower, 1.6
liter DOHC turbocharged engine, four-wheel disc brakes and a
floor pan that's 20 percent stiffer than the plain vanilla
323. This package is suspended by MacPherson struts in front
and Mazda's Twin Trapezoidal Link setup in back, with front
and rear stabilizer bars. The four-wheel-drive system uses a
center differential with a lightweight planetary gear that
splits torque 50:50 between the front and rear axles.
The GTX handles well, particularly on loose surfaces, and
boasts brisk acceleration. It offers great seats, a
tremendous amount of headroom and the rear hatch can swallow
a spare set of tires and all the associated gear for a
weekend of autocrossing. One of its strongest suits is its
predictability at the limit-the GTX never surprises the
But of course, we're never satisfied and sought to tune
our 323 for spirited driving on mountain roads. We wanted to
reduce understeer by increasing grip, reduce body roll for
improved transient response, and boost power and torque.
Our 90,000-mile Mazda 323 GTX rally car helped us win the
1993 California Rally Series championship, the 1994 SCCA
Southern Pacific Divisional PRO Rally Championship, and the
1993 CRS Rookie of the Year driver and co-driver titles. So
we figured we would apply what we learned preparing the
rally car to a street application. We chose a 323 GTX
because of the economies of scale and parts
interchangeability of driving the same type car we race.
However, we could have selected any number of platforms for
We wanted a chase car that would handle well and survive
hard driving on less-than-ideal roads, yet would be fun and
practical for everyday driving. We wanted it to be capable
of competing in an autocross with the potential to become a
rally car - in case I wrote off the race car.
I asked Road/Race Autosport in Los Alamitos, California,
to do the work. Road/Race had prepared and maintained the
rally car. Scott Webb, a road racing champion and the former
marketing director for HKS USA, and Mike Welch, an expert at
fabrication and race preparation, founded Road/Race last
year. The company specializes in preparing imported cars,
mostly Japanese, for street and race applications and has
become one of the fastest growing shops of its type in
We located a GTX with more than 120,000 miles on the
clock, but it had not been crashed or modified.
Hood vents reduce temperatures under hood by allowing hot
air to exit.
Lower stress bar increases rigidity by tying lower
control arm pivot points. Front strut bar increases body
rigidity, eliminates tendency of strut towers to rotate
inward and gravitate toward center of car.
Parking lot dings were repaired and the upper two thirds
of the body was repainted black, easier and less expensive
than painting it the original metallic charcoal. Road/Race
Autosport installed a pair of hood ducts developed for
rallying that reduced engine temperatures by allowing hot
air to exit.
Our objectives with the suspension were in conflict: We
wanted a relatively low street/autocross setup that could
later be raised for rallying. So Road/Race designed a strut
suspension employing adjustable spring perches, Tokico gas
strut cartridges and Eibach springs.
This system provided a dramatic improvement, reducing
body roll significantly. While the worn stock suspension was
bottoming in dips, the new suspension provided excellent
resistance to compression - in spite of a reduction in ride
height of more than two inches.
The biggest gain, however, was in transient response.
With its sacked suspension, the old GTX was a chore to
drive. The improved damping of the Tokicos and higher spring
rates of the Eibachs transformed the 323 into a race car
with superb transient response. The anti-roll bars were left
alone; too much roll stiffness would only result in lifting
wheels in tight, bumpy corners.
The adjustable perches provide quick adjustment of ride
height, allowing us to easily raise or lower the car nearly
four inches. We can alter the ride height when switching
between street, autocross and off road (snow and gravel)
setups. If we need to prepare the car for rallying, we can
install a set of rally springs and adjust the height
accordingly. If adjusting ride heights is not important and
your car is more mainstream than our GTX, then you'd
probably do better with a standard Tokico strut
To increase structural rigidity, Road/Race installed
front and rear strut bars that tie the tops of the strut
towers together, along with a front lower stress bar
attached to the lower control arm pivot points. The front
strut bar and lower stress bar reduce chassis flex and
eliminate the tendency of the strut towers to twist and fold
inward-a real problem on the rally car.
Road/Race developed the rear strut tower bar, called a
Solo Bar, to perform the same duty on the street car
performed by the roll cage on the rally car. Road/Race
designed its Solo Bar to increase chassis rigidity and to
serve as a mounting point for a competition safety
We chose Yokohama 205/45-VR16 AVS Intermediate tires
mounted on TSW Hockenheim 16x7.5 inch alloy wheels to
complete the handling package. We were impressed with the
racing heritage of TSW and liked the rally/European Touring
Car look the 16 inch wheels gave the car. The Yokohama AVSs
offered the balance of high performance and wet weather
capability we were seeking.
To boost power output, we freshened the engine and
installed an HKS manual boost control and HKS PFC F-CON fuel
controller. We added an HKS muffler and a Megs exhaust tip
that resulted in a pleasing exhaust note without violating
As in the rally car, we employed 20W50 Torco synthetic
racing oil in the engine and Torco synthetic gear oil in the
gearbox. The weak link in the 323 GTX drive train is the
gearbox. To further protect this link and increase
performance, we installed a Centerforce dual-friction
racing clutch assembly.
This equipment lowered our 20-60 mph times by a full
second. We were more interested in getting around slow
moving vehicles on mountain roads, than standing-start
To protect our investment, Road/Race installed an
attractive Sigtronics digital exhaust gas temperature gauge
that is inexpensive, but provides precise readings of
combustion temperatures. We also installed a VDO turbo boost
gauge to replace the inadequate stock readout. A GReddy
turbo timer was installed, which we found handsome, easy to
use and relatively inexpensive.
Tokico gas strut cartridges and Eibach springs work well
with Road/Race's adjustable perches. Note the braided steel
Inside, we fitted a Momo Benetton Evolution 2 steering
wheel, a Momo Competition shift knob and a set of Road/Race
aluminum drilled pedals with a massive dead pedal-all
identical to the components used in the rally car. We
installed a set of Schroth Autocontrol Harnessbelts that
provide increased safety and driver control, yet are
comfortable and easy to use. The Schroth (pronounced Shrote)
belts are the only belts on the market approved by the
With the work we put into it, our 323 GTX was still an
inexpensive car, yet offers phenomenal performance, is fun
to drive and attracts compliments regularly. All it needs
now is a big set of rally lights and some mud flaps.