It’s easy to identify a go-fast Impreza when you’re poised, raring-to-go at
the traffic lights.
Keep an eye out for a bonnet scoop and ‘W-R-X’ lettering on the boot lid and
you know you’re up against something quick. But if there’s no bonnet scoop
and tell-tale badging, you’ve got no reason to sweat - any ol’ Falcodore will
leave this ‘sleepie Subie’ in its dust.
But don’t be too confident – not all sleepy Subies are as they seem...
This 2002 Impreza RS – owned by a nameless Melbournian – looks like a nice
clean example from someone who takes a little bit extra pride in their
machine. The clear-lens taillights and dual outlet polished rear muffler let you
know the car isn’t an unwanted game-show prize. And then you notice the
personalised number plates. Hmm, what does T-H-E-W-L-F spell?
RRRAAAAHHHHH!
Too late.
You’re wasted.
If you were a little bit quicker on the uptake you’d realise those plates
mean ‘The Wolf’ – as in, a wolf in sheep’s clothing. And, yes, these plates
really are warranted!
Under the bonnet of this mild-looking Impreza RS is the standard 2.5 litre
DOHC flat-four – with a turbo conversion! That’s right, Mr X passed up buying a
showroom-stock WRX for an Impreza RS with hidden performance.
There are many advantages to this approach. The biggest advantage is the
spread of low-to-mid rpm torque, which makes the car much easier to launch
without bogging down. The other advantage is, of course, the sleeper appeal.
The Impreza RS turbo kit is the product of Melbourne’s AVO (Advanced Vehicle
Operations). In Stage One guise – as fitted here – the turbo kit comprises a
replacement up-pipe (which bolts to the factory exhaust manifold) and a 320hp
ball-bearing turbocharger with all necessary lines and hoses. A mandrel bent
inlet pipe delivers induction air to the compressor through an AVO pod filter.
The factory over-the-radiator cold air duct remains in place to help give the
filter some relief from under-bonnet temperatures.
Speaking of temperature relief, the heated charge-air from the turbo
compressor is chilled by a plenty-big front-mount air-to-air intercooler. This
is an optional upgrade from AVO’s base Stage One kit, which normally comes with
a top-mount style intercooler. The intercooler plumbing is mandrel bent and
there’s an AVO atmospheric-venting blow-off valve fitted immediately prior to
the throttle body.
From the turbine housing, the 2.5’s exhaust gas is flung through a 2½ inch
diameter dump pipe that’s also included as part of AVO’s Stage One kit. A
high-flow exhaust is available but the standard exhaust remains in service – for
now. The only exhaust mod is the dual outlet Magnaflow rear muffler, which gives
the car its characteristic flat-four soundtrack.
In Stage One configuration, extra fuelling comes from the addition of a ’80
horsepower’ extra injector mounted before the throttle. This is driven by a Link
micro-fueller controller, which teams with the standard Subaru management
system. The fuel pump and pressure regulator remain standard, which means
there’s a limit to how much power can be produced.
The Stage One configuration increases power to just over 120kW at all four
wheels (as measured on AVO’s DTS chassis dyno). This power output is achieved on
just 4-5 psi boost, which means there’s no need for an aftermarket boost
controller – all that’s needed is a hose from the compressor outlet to the
wastegate actuator.
Note that Stage 2 involves an upgraded fuel system and around 9 psi of boost,
which achieves around 150kW at all four wheels.
This is a l-o-n-g way from the factory 112kW flywheel figure.
Mr X says the turbocharged engine pulls very strongly at all revs and there
isn’t the agonising lack of low-down grunt experienced in 2.0 litre WRXs. But the
long-stroke four isn’t a big revver as the power curve starts to nose
over at about 5500 rpm. This is around 1000 rpm shy of redline.
So far, Mr X has had no grief from the standard Subaru driveline – and you’d
hope not, considering the turbo kit has been fitted for less than a year.
The standard Impreza RS is widely praised for its WRX-like handling and grip
so Mr X hasn’t needed to modify the original suspension. The brakes have also
escaped spanners and sockets.
The interior of the RS already comes decked out with wrap-around seats and a
standard Momo airbag steering wheel. All Mr X has added are aluminium sports
pedals. We’ve gotta say, though, the factory 220 km/h speedo is no longer up to
the task.
So where does The Wolf slink to from here? Well, Mr X planned to revise the
fuel system and increase boost but has recently decided to sell the beast. If
anyone likes the idea of causing absolute dismay at the traffic lights, contact
AVO for the contact details of Mr X.
Just mention The Wolf...
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