Having modified more than a
thousand LS1s it’s fair to say that Steve Mathews of Melbourne’s F1 Performance knows
his bent-eights. He’s done it all - everything from the most minor bolt-on to a
full-house twin-turbo stoker!
It’s obvious Steve has confidence in his work when you hear he bought this
2003 Holden CV8 Monaro 6 speed purely as a development and promo car. Whenever
Steve has a customer asking about performance mods to suit the LS1, he takes ‘em
for a spin - it’s the perfect vehicle to get owners reaching into their
pockets!
“What we’ve done is put together a car that offers HSV GTS beating
performance at a total [upgrade] cost of around AUD$12,000,” says Steve. So what needs to
be done to bridge the gap to the mighty 300kW C4B in the GTS, you ask?
Well, the F1 upgrade starts with a custom stainless steel airbox containing a
K&N pod filter. Steve says a custom airbox was required to fit the larger
surface area of the pod filter. Induction air then passes through a smooth-wall
GTS MAF pipe into an 84mm bore throttle body. These mods let the engine generate
more power as well as enabling it to fill its lungs with air as soon as you touch
the throttle.
The exhaust system is also addressed. While the standard Holden system isn’t
too bad for a factory effort, F1 replaces the whole system from the alloy heads
back. Up front, Pacemaker 1¾ inch primary 4>1 headers are used in
conjunction with DiFillipo twin 2½ inch pipes. A pair of DiFilipo 3 inch high
flow cat converters and high-flow mufflers ensure minimum restriction.
It’s all well and good to throw these bolt-ons in the LS1’s direction
but you won’t see optimum power or driveability unless the engine management
system is altered in some way. F1 Performance gets into the factory ECU and
remaps it using LS1 Edit software. Note that the standard airflow meter is also
removed and a MAP sensor is brought in as the load sensor. The fuel system is
untouched.
So far, these mods – intake, exhaust and MAF-less tune – amount to around
AUD$3600. Power at this point is around 240kW at the wheels, up from about 170
in standard form (as measured on a Dyno Dynamics chassis dyno).
For still more power, the F1 upgrade calls for a new camshaft and associated
hardware. The CV8 is equipped with a very mild cam upgrade that has a barely
noticeable effect on idle quality. Competition valve springs and titanium
retainers are also included. The standard timing gear is kept in service.
Power output (with a suitable tune to suit the cam) is now up to about 270kW
at the wheels - about 30kW ATW clear of the factory GTS. The extra cost for the
cam upgrade is AUD$2800, bringing the tally up to just AUD$6400.
About now – depending on how the car is driven and whether you’ve stuffed big
tyres under the rear – the standard clutch might start to slip. F1 replaces the
OE part with a single plate upgrade clutch that retains factory-like pedal
weighting and feel.
A much better overall on-road package is created by adding a KAAZ LSD. Steve
says there’s no comparison to the stock diff centre – the KAAZ product gives
better traction and is much smoother in operation.
In this guise, the F1 Performance CV8 has run a 12.8 second quarter mile at
110 mph. Note, however, slick rear tyres were used to achieve grip on the
slippery drag strip surface.
The suspension settings of LS1 powered Holdens and HSVs vary considerable
across different models. F1 brings them all more-or-less in-line with Koni
adjustable dampers front and rear and lowered King springs. Noltec bushes are
also used throughout the suspension providing improved feel and handling
sharpness.
The brakes also come in for enhancement. The F1 upgrade package involves
installation of 30mm larger diameter front rotors and ventilated rear rotors –
both slotted. All new Corvette-style callipers and pads are supplied, as are
braided lines for the front. These provide a significant braking improvement
over the base LS1 anchors.
Total cost for all the above engine work, clutch, diff, brakes and suspension
is AUD$12,040 (fitted and tuned). Not bad at all if you ask us.
For the promo car, Steve’s personal tastes led him in the direction of 18
inch VY Series 1 Clubsport R8 rims. These suit the clean, simple styling of the
CV8 and the 235/40 and 245/40 Bridegstone S-03s fill the guards nicely. The only
other visual mods are the fitment of ‘427’ Monaro tail lights and a full
colour-coding treatment.
Inside, the F1 CV8 is standard except for contrasting yellow stitching on the
handbrake lever, gear shift boot and steering wheel. A HSV gear knob is also
installed. The audio system remains stock – the current range of head units is
far better than the old pre-VY system!
From here, Steve is developing an upgrade that brings 11 second quarter miles
while still maintaining excellent street-ability. This will incorporate head
work, pushrods and a bigger camshaft – and it’ll cost just a few hundred bucks
more than the existing package.
Stay tuned!
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