It’s
easy to see the appeal of time attack. Besides drag racing,
there aren’t too many motorsport categories where winning can be
measured in more ways than one, but in chasing the clock on top of
gunning for class honours, time attack does just that. It’s also a
motorsport where modifications are largely only limited by imagination,
but at the same time it remains totally accessible even for those on
modest budgets.
With the 2015 edition of the Yokohama World Time Attack Challenge kicking off
on Friday local time at Sydney Motorsport Park in Australia, we thought
it was the perfect opportunity to take a look at a machine that
competed at the very first WTAC event five years ago – the Turbosmart Open Class FC3S Mazda RX-7. Unlike
many high-profile time attack builds that have been engineered from the
ground up for the purpose, this particular car was originally built for
a different motorsport genre, namely tarmac rallying. It was successful
in the hands of its owner, Turbosmart’s CEO Nic Cooper, too, notably
placing first outright in the hard-fought Modern Classic Turbo
division of the 2010 Clipsal 500 Adelaide Rally. Later
that year the RX-7 was entered in the WTAC – an event which became the
catalyst for a complete time attack focussed makeover for 2011.
All
of the preparation work except the engine build and tuning was carried
out in-house, and when the time came to put it all on the line
at Eastern Creek International Raceway (now known as Sydney Motorsport
Park), Turbosmart’s General Manager Stewart Mahony turned in a 1:38.5720
lap, which you can watch above. Given it was a fresh build there were
some technical challenges along the way, but it was still a quick enough
time for the team to rank 12th out of the 57 competitors in the
Open Class. While
all this was going on, the FC3S was serving another, more important
purpose for Turbosmart – that of a research and development
testbed. More specifically, the RX-7 was (and still is) used to evaluate
new and existing products in a real-world race car scenario; its
hard-tuned 13B providing an extreme environment for theories to be
proved and new technologies to be assessed. Think wastegate diaphragm
materials, spring alloys and valve coatings… At
face value though, this is a good looking car. As the world’s quickest
time attack machines push to shave hundredths of seconds off their best
lap times, the wilder they’re getting. I’m all for crazy aero and love
the science behind it even if I can’t really understand it, but I think
there’s still a lot to be said for a simple, almost street tuner like
approach. I can easily picture Turbosmart’s FC3S parked up at Daikoku Futo PA on 7’s Day. The
body features a Shine Auto Project front bumper with canards integrated
into a one-off splitter, Shine side skirts with custom extensions, and a
Shine diffuser fitted beneath the RX-7’s factory rear bumper. You’ll
also find a vented carbon fibre bonnet, a headlight conversion and to
finish things off, a large APR rear wing out back. And it needs all the
downforce it can get too, because thanks to an angry engine, the FC is
capable of crazy speed.
CHAPTER TWO
Powered by Pac
Turbosmart
didn’t have to look far to find a workshop capable of piecing together a
powerful and reliable motor package either. Sydney-based Pac
Performance is not only a globally-known name in rotary engine building,
tuning and racing, it’s a staunch supporter of Turbosmart products,
which are used all the way up to its Mazda6 SP drag car, which runs a methanol-fuelled 20B and turns in 6-second quarters at 200mph+.
Nothing quite that extreme was required for Turbosmart’s time attacker,
but its PAC-built 13B turbo that’s been bridge-ported for flow and
dowelled for strength is a serious piece of power-making hardware in its
own right. One
of the more recent upgrades made under the hood is the Garrett GTX4088R
turbocharger – a unit that can support up to 850hp. In this instance
there isn’t much wasted potential either. For boost control, a 50mm
Turbosmart Pro-Gate 50 wastegate is employed, complete with a Turbosmart
Wastegate Sensor Cap. Through the use of an internal valve sensor, that
accessory provides data on the operation of the wastegate relayed via
the Racepak/Haltech IQ3 unit in the cabin. Pac
also pieced together a front-mount intercooler with custom pipework
that’s plumbed up using Turbosmart silicone hoses and Murray clamps. To
relieve excess pressure in the intake tract when the throttle shuts,
a Turbosmart Race Port blow-off valve is employed. In
preparing the RX-7 for time attack duties, the 13B was repositioned
lower and slightly further back in the engine bay on stiffened mounts to
improve weight distribution and better the handling and balance,
something that makes the tiny twin-rotor block assembly even harder to
make out beneath all of the ancillary items. For a small engine it packs
a hefty punch, and fueling that fire is E85 bioethanol. The
setup features two Bosch 044 pumps and a custom surge tank in the
rear, feeding Teflon-coated fuel lines connected up with Speedflow 200
Series fittings. In the engine bay you’ll find a Turbosmart FPR2000
adjustable fuel pressure regulator and Injector Dynamics ID2000
injectors. Bosch ignition coils provide the spark energy. As
is the case with any rotary engine, tuned up or otherwise, heat is real
issue. Keeping temperatures in check is a PWR aluminium race radiator
and a Davis Craig EWP130 electric water pump that’s controlled by the
ECU, plus a pair of Setrab 25-row oil coolers. There
are other details too, like a custom aluminium catch can, DCI heat
sheilding and the application of Hi Octane performance coating on the
intake plenum.
But I’m sure what you’re really wanting to know by now is just how much power the whole setup is producing…
Well,
it’s hard to say exactly, because as you’ll see by watching the video
above, the FC3S had trouble sitting properly on the dyno and maintaining
traction when Rocky Rehayem of Pac Performance tuned the Haltech
Platinum Sport 2000 engine management system. But according
to Turbosmart, it’s around 700whp, via a Toyota Supra gearbox running
out to a Cusco 1.5-way LSD equipped rear end.
FINAL CHAPTER
Form Meets Function
From
a purely visual standpoint the RX-7 sits perfectly, but beneath the
bodywork it’s every bit as modified as you’d expect for a dedicated
track car. Custom-valved Bilstein coil-over dampers with Eibach springs
(10kg front, 11kg rear) feature at all four corners, with Whiteline
blade adjustable sway bars front and rear, Super Now lateral control
arms and a full course of Whiteline Chassis Control bushings. The
braking system is equally impressive with Project Mu 6-piston and
4-piston forged callipers featuring at the front and rear over 355mm
slotted 2-piece rotors from the same maker. Turbosmart machined the
rotor hats and fabricated up some custom calliper mounts in-house,
before piecing the whole package together with stainless steel braided
brake hoses and Project Mu Club Racer RC09 pads. I’m sure you’ll agree
that the lightweight Advan Racing RS wheels in a 18×8.5-inch +38 fitment
are a good look too. Although
the FC3S is a light car by modern standards, pulling as much weight out
of the chassis was treated with the same importance as every other
aspect of the time attack rebuild. And as you’d expect, the interior
is all business, beginning with a Pac Performance built rollcage and an
aluminium dash panel. The seat, harness belts and suede-wrapped steering
wheel are all by Sparco. Along
with the aforementioned ECU, project partner Haltech (another
Australian company) also supplied the TC4 thermocouple amplifier, CAN
hub and dual channel wide-band modules, and they’re all neatly laid out
alongside the required electrical relays and fuses in the passenger side
footwell. Haltech’s
IQ3 by Racepak unit displays all the vital engine information via its
digital screen, and backs it up with full data-logging for post-run
analysis.
The
only other performance and monitoring tool present in the cockpit, and
in clear view from the driver’s seat, is the Turbosmart
e-Boost2 electronic boost controller/gauge.
Final
touches include a custom panel for toggle switches and the starter
button, an adjustable brake bias and a hydraulic handbrake. Call it pure
function.
Despite
its credentials, it’s unlikely that the Turbosmart’s FC3S with see
WTAC competition again. But that’s okay, because from a time attack
perspective it achieved everything it set out to do in 2011, and it’s
not like it doesn’t see track time on a regular basis through its
ongoing product R&D endeavours and other opportunities that present
themselves.
As a side note, the location for this shoot
was Turbosmart’s huge new Sydney design studio and state-of-the-art
production factory, which now is fully operational and cranking out more
product than ever before. Look out for a behind-the-scenes tour of the
facility in the near future.
Turbosmart’s Mazda RX-7 (FC3S) Numbers
Max Power: Estimated 700whp Engine
Pac Performance built 13BT, bridge-ported & doweled, Garrett
GTX4088R turbocharger, Pac intercooler with custom piping, Turbosmart
Pro-Gate50 external wastegate with sensor cap, Turbosmart Race
Port blow-off valve, 2x Bosch 044 fuel pumps, custom surge tank, braided
stainless steel Teflon-coated fuel lines, Speedflow 200 Series
fittings, Injector Dynamics ID2000 injectors, Turbosmart FPR2000
adjustable fuel pressure regulator, Davis Craig EWP130 electric water
pump (controlled by ECU), Hi Octane performance coatings, DCI heat
shielding, 2x Setrab 25-row oil coolers, PWR aluminium race
radiator, Turbosmart silicone hoses, Haltech Platinum Sport 2000 engine
management system, stiffened engine mounts Driveline
Toyota Supra gearbox, Cusco 1.5-way limited slip differential, solid gearbox mounts Suspension/Brakes
Custom-valved Bilstein coil-over
shock absorbers (front/rear), 10kg Eibach springs (front), 11kg Eibach
springs (rear),Whiteline adjustable sway bars (front/rear), Super Now
lateral control arms, Whiteline bushes, solid-mounted rear subframe,
Project Mu 355mm 2-piece rotors, 6-piston forged sports calipers
(front), Project Mu 355mm 2-piece rotors, 4-piston forged sports
calipers (rear), Project Mu RC09 Club Racer pads (front/rear), braided
lines (front/rear), Turbosmart machined rotor hats & caliper mounts
(front/rear), brake bias adjuster, hydraulic handbrake Wheels/Tyres
Advan RS 18×8.5 +38 wheels (front/rear), Yokohama Advan A050 255/35R18 semi-slicks (front/rear) Exterior
Shine Auto front bumper, custom built front splitter, factory FC3S rear
bumper with Shine Auto diffuser, Shine Auto side skirts with custom
extensions, APR rear wing, headlight conversion Interior
Pac Performance rollcage, Sparco Evo Plus seat, Sparco 5-point harness
belts, Racepak/Haltech IQ3 digital dash display, Turbosmart e-Boost 2
boost controller
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