What is it about a tuned V8 that's so
irresistible? Is it the ground-shaking grunt? The glorious bellow? Maybe it's
the sheer power. Whatever it is, Nicholas of Melbourne is completely hooked and
there's no way you'd force him into the seat of something like a WRX. This is
Nicholas' second HSV and his second modified LS1 - he previously owned a VT
Series 2 LS1 with a bunch of bolt-on muscle. "Before I got the GTO about 15
months ago I was intending to buy a Clubsport R8," says Nicholas. "I decided not
to get the R8 because I really wanted leather and I knew the two-door body is a
lot more rigid than the sedan. It's the one to choose if you want to build it
up."
Five-point-seven litres of bent-eight grunt, a
6-speed 'box and all the HSV fruit would be enough to keep most buyers content -
but not Nicholas. "Of course, it was down on the performance of my modified VT
but it was very smooth and driveable. I was pretty stoked with it," he says. Not
that Nicholas had much time to build an appreciation for the standard
output...
On the first day of ownership, Nicholas took the
GTO along to trusted friend and LS1 guru Steve Mathews of Melbourne's F1
Performance. The first mods were nothing out of the ordinary - an air intake and
exhaust. The airbox is an in-house F1 Performance development made from sheet
aluminium and contains a K&N filter. Further intake airflow comes from a
'de-screened' airflow meter, replacement MAF tube and SS Inductions throttle
body. The exhaust improvement initially employed Pacemaker 4>1 headers
leading into twin 2½-inch pipes. DiPhillipo extractors - boasting larger
diameter primaries - are now fitted along with 3-inch cats.
"At that stage I was after a nice note as much as
the extra go," says Nicholas. Still, after Steve remapped the ECU using LS1 Edit
software, a substantial 17 percent power increase was netted - the factory
196-ish ATW kilowatt output had been bumped up to 230kW. Not bad.
Before attempting to find more kilowatts, Nicholas
turned his attention to the suspension and brakes. A Bilstein/Quadrant damper and
spring combo along with Whiteline adjustable swaybars, front strut bar and
aftermarket bushes keeps the hairy-chested rear-wheel-drive GTO pointing the
right way at all times. Harrop 343 and 300mm slotted discs also serve to prevent
accidental rearrangement of those beautiful panels. Braided brake lines and a
mix of RaceBrake and Pagid pads perform well on the street and the track. A
power steering cooler was also seen as essential for track duties - the factory
power steering system is known to boil over when pushed hard.
And now the engine department really gets
serious.
Internally, the 5.7-litre all-alloy V8 has
recently been treated to a CompCams camshaft with uprated springs and retainers,
Yella Terra 1.7 ratio roller rockers and the heads have been ported in-house.
The compression ratio has also been upped to around 10.8:1 (about as far as
you'd want to go using everyday PULP) thanks to skimmed cylinder head surfaces.
A Hi-Energy 8-litre baffled sump and a modified and blueprinted oil pump are
also fitted.
Like this isn't enough, Nicholas enjoys the extra
speed that only giggle gas can deliver. Yep, pop the bonnet and you'll see a wet
nitrous system that squirts a 120hp shot into the intake manifold - "but only
for drags," explains Nicholas... Steve from F1 Performance adds that nitrous was
previously squirted into the intake before the airflow meter. We're told that
this required two separate sets of maps (ie a tune specific to running the engine
with and without nitrous) and that the current arrangement is much happier. A
thermostat-controlled bottle warmer is yet to be added to maintain the optimum
nitrous pressure.
And what are the car's drag times, you ask?
Well, the best time down the quarter mile so far
has been an 11.9 ET at 120 mph. That was achieved wearing DOT-legal radials.
Steve says the car makes around 290kW at the wheels without gas, but around 350
with the shot in the arm.
The stock clutch isn't designed to handle that
level of grunt and has been replaced by a MacLeod heavy-duty arrangement
comprising clutch, pressure plate and flywheel. The 6-speed gearbox remains
standard except for a F1 Performance 40 percent short-shift mechanism. Heading
toward the rear, the diff features a shorter 3.91:1 ratio with a KAAZ
torque-biasing LSD centre. Just what you need to leave the line in a hurry!
Each of those flowing guards houses a GTS 19-inch
rim wearing a 245/35 Bridgestone S03. Bridgestone RE55 DOT slicks are fitted to
the stock 18-inch rims whenever Nicholas takes to the track.
Inside, the oh-so comfortable GTO leather seats
have proven suitable for both street and track duties. The added performance and
engine mods has seen the fitment of a shift-light, chequerplate accelerator
pedal and AutoMeter gauges for oil pressure, water temperature and battery
voltage. The nitrous system is armed by a pair of aviation style switches - a
very neat installation.
Nicholas also likes listening to quality tunes and
has decked out his GTO with a bunch of pro-grade sound gear. The system is
headed by a flip-out Kenwood 10-stack CD/tuner, which is wired a SoundStream
LittleWonder amp and a larger Kenwood 2-channel amp. These amps drive a pair of
Focal 6½-inch splits and Kenwood 12-inch subs respectively.
With 11-second quarter mile performance, the
ability to circuit race
and cruise the 'burbs without misbehaving, it's
little wonder Nicholas is very happy with his modified GTO. But things don't
stand still. Nicholas has purchased a set of OZ Racing rims, which are
apparently the same as were meant to go onto the factory 427 Monaro. And then
there are the plans for some more engine work... something like
twin-turbochargers!
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