Running an 11 second quarter mile in a Subaru
Impreza is nothing to be sneezed at. Sure, you’re probably aware that you can
turn a WRX into a lightning-quick streeter with some basic bolt-on mods but an
11 second ET is generally beyond ‘the basics’ – a stroker engine or a massively
oversized turbocharger are the usual ingredients.
But the AutoTech Engineering MY00 Impreza STi –
owned by workshop proprietor, Spiro – is an exception.
Spiro lets it be known that he’s pushing the
envelope of bolt-on mods – this isn’t the level of tune he’d be
comfortable handling to a customer. With the selected turbocharger pumping in up
to 24 psi boost to achieve an 11.7 second ET, the standard engine internals are
being pushed to their limit.
Spiro says his ’00 four-door STi was bought as a
development and promo car to showcase the talents of his business as well as the
range of APS (Air Power Systems) products. Of course, there’s also some personal
satisfaction that comes from purchasing a new STi...
Under the bonnet, you’ll find a treasure chest of APS gear. The standard
top-mount intercooler has been ditched to make way for an APS bar-and-plate
front-mount ‘cooler which comes as a kit complete with mandrel bent plumbing and
silicone hoses.
An adjustable recirculating blow-off valve is also installed.
Routing induction air to and from the core requires a long length of plumbing
and you’ll find the standard airbox has been sacrificed to make space. APS
replaces the stock ‘box with a cold air induction set-up with a pod filter
mounted within the inner guard.
The standard STi turbocharger is quite large for a 2-litre production vehicle
but it can’t comfortably propel the Subie into the 11s. Again, APS comes to the
rescue with a bolt-on SR40 turbocharger which is claimed to support applications
up to almost 330kW while maintaining good response. From the back of the turbo,
exhaust gasses flow through an APS 3 inch mandrel bent exhaust system.
With a massive increase in engine airflow, Sprio was able to tune
the fuel, ignition timing and boost control using a UniChip interceptor. The
UniChip has no sweat controlling a set of 600cc injectors. Amazingly, the rest
of the fuel system remains standard - Spiro says he can’t understand why people
upgrade the fuel pump at this level of modification. The standard pump is
perfectly happy maintaining an air-fuel ratio of 11.7:1 at maximum power. And
how much power are we looking at?
Well, with the turbo set to deliver
24 psi boost, Spiro says the car typically punches out 238 – 242kW at all four
wheels (as measured on a Dynamics chassis dyno). This equates to somewhere
around 370kW at the flywheel – not bad for a 2-litre! Backing the engine is an
Xtreme heavy-duty organic clutch which seems to be performing fine so far - the
standard clutch threw in the towel at the drags. The standard STi gearbox has
escaped damage thanks to a relatively sympathetic driving style and the use of
Mobil lubricants. Diffs are standard short-ratio STi.
The STi comes
pretty well equipped in the suspension and brake department so all that’s been
changed are the springs, discs and pads. Pedders springs bring the ride height
down slightly while the STi anchors feature slotted DBA discs and
high-temperature pads. These do a good job blackening the Volk
style 18 inch alloys.
Looking at the photos, it’s easy to assume that a
wild aftermarket body kit has been added – or at least a different rear wing.
Well, guess again – the body is 100 percent standard except for some paint work
performed by RSV in Glanville. Perhaps inevitably, the hard-pushed STi engine
bit the dust not long after our photo shoot. Spiro knew he was r-e-a-l-l-y
pushing his luck when he bumped the boost up to 28 psi, so he wasn’t surprised
to learn of two bent rods shortly long after. Okay, so that’s the limit of this
configuration!
Since the original engine died, the STi has been
revived with a 2.2-litre stroker kit and a larger capacity APS SR50
turbocharger. Sprio says he’s expecting a reliable 280 – 290kW at the wheels
along with much improved all-round torque. Note that the newly built engine runs
Aries forged pistons providing an 8.7:1 static compression ratio, which is
considerably higher than standard. The high static compression ratio ensures the
2.2 donk offers maximum driving flexibility. Testament to this, the car is
currently employed as a get-around ‘hack’ by Autotech Engineering’s foreman. No
special treatment here! And that’s what a development car is all about. Finding
a combination that works, exploring the limits and making sure the car is still
happy as a get-around machine. It just happens that this STi can ‘get around’
very, very quickly...
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