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Scorpion Sting

We all know to keep away from the tail of a Scorpion. But if you dare to take this one on, we guarantee the last thing you'll see is it's tail!

Words by Michael Knowling, Pix by Julian Edgar

Click on pics to view larger images


If you pulled up alongside this mild-looking silver Scorpion at a set of lights, what would you think - that those 17s are there for pose value and that it doesn't have much more than 80-odd kW of Astron power under the lid? But then what if the guy behind the wheel started revving up for a show of hi-performance strength - yeah, chances are you'd be willing take him on! "This poor bastard is gonna get wiped" you'd be laughing to your backseat mates as you'd slide the Momo into first.

But just as you'd pop the clutch - expecting to massacre the old Mitsu - there'd be an almighty eruption of noise from the next lane. The wail of tyres, the roar of a 3 inch exhaust - and the whiz of a high pressure T04! Your machine more than likely would get blown to the side of the road... and then you'd sure cop barbs and ironic pats on the back from your ever-faithful and supportive buddies.

Another Scorpion sting.....

But it doesn't have to be this way. Just so long as you remember that there a people like Gary around that like to pack an awesome hit in a conservative wrapper.

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And when we say awesome - we mean it. The engine that is responsible for such acts of indecency is very closely based on one used in a fully prep'd racecar. Steve Knight - a Mitsubishi employee and guru of the marque - built up these engines for his Lancer (and now-rolled Sigma), but later decided to opt for a more sophisticated twin cam turbo engine. Having demonstrated the single cam's performance strength on the local Adelaide racetrack (where no other car in the Club Car formula could then out-grunt it) Gary leapt at the opportunity of buying a virtually identical motor.

Gary had purchased the ideal recipient for the T04 motor around four years previously - a genuine one (elderly) owner Mitsubishi Scorpion in 100% original condition. It seems that this car's plans for a peaceful retirement have been discarded! Although the asking price of the car was a little more than for the average example, the panels on the car were so immaculate they remain untouched even today. The same goes for the paint - it's 100% ridgey-didge Mitsubishi, in perfect nick. Bringing the car up to par visually is a set of Simmons FR17s sprayed in Falken 215/40 and 225/40 rubber at the front and rear.

Gary has added just a small indication to the car's performance in the form of an original Sigma turbo bonnet vent on the right hand side. The main reason for this is to allow heat from the turbo to escape from under the bonnet, and especially away from the nearby brake master cylinder.

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The turbo unit itself is a T04 with a Sierra Cosworth compressor side and is the product of Adelaide Turbo Service. While it may seem a bit on the large side at first glance, the engine's 2.6 litres helps to keep lag to a minimum. According to Gary, maximum boost pressure of 15 psi is also achieved at a road use friendly 3500-4000 rpm. One other interesting point is that runs a 34mm external wastegate to bypass excess amounts of turbine gas.

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The Scorpion's turbo-induced swollen intake temperatures are brought back down to near ambient thanks to an intercooler. Located in the car's front airflow, the highly efficient core came from Adelaide's Turbo Tune and delivers a virtually undetectable pressure drop. Mandrel bent intercooler plumbing makes the journey to and from the core even more free flowing.

A couple of weeks before our photo shoot, Gary fitted a Japanese brand blow-off valve to the turbo system in the hope of reducing the car's post gear change lack of instant torque. Alas it gave no advantage - in fact the car went slower and so off came the blow-off valve.

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The internals of the 2.6 litre engine are nearly the same as was used to power the racecar. It packs 40 thou oversized ACL dished pistons, and high quality TRW rods and bolts. The cylinder head has been swapped for a TR series Magna item which gives the benefits of larger ports, valves and a larger combustion chamber to lower the static compression ratio to 7.46:1. The intake hardware has gone EFI with the manifold kindly donated from a TR Magna. But to fit this set up, which was originally designed for a front wheel drive layout, the large diameter TR throttle body had to be swapped to the other end of the plenum.

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The fuel system begins with a Goss pick-up pump that puts fuel into custom swirl pot situated in the boot. With fuel surge problems then taken care of, it gets pushed by a V8 Commodore pump through 5/16 inch lines up to the standard Magna fuel rail that branches out in to a set of four Bosch 803 injectors. With fuel pressure maintained by the stock regulator, the injectors are currently at their maximum flow to produce the peak 175kW at-the-wheels figure. The fuel and ignition show is conducted by a Haltech E6A ECU that takes its main inputs from a dizzy, throttle position and a MAP sensor. From this acquired information it has been calibrated to fire the single coil unit and Bosch 803s for maximum torque across the rev range. The system operates in open-loop so Gary can choose to run leaded fuels if he gets the urge.

A full 3 inch mandrel bent exhaust system made by Exhaust Technology hangs off the turbo and wastegate outlet, while a single HKS Super Drager muffler keeps the dBs to a manageable level. In fact, we could hardly believe it just had the single 'box, its burble was so hushed.

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The scorpion's tail comprises a factory 3.55:1 differential that's recently been locked (welded) to give maximum traction off the line. The downside is that characteristic hop-hopping whenever the car has to negotiate a tight turn, so the car isn't driven quite as often on the road as it once was. Oh well, we can't have everything for nothing. Once he saves up the 2000 or so dollars for a conversion, Gary does intend to install a Commodore limited slip diff combined with Nissan Skyline rear discs.

With approximately three times the car's factory power output, Gary admits there is still a need to up-spec the four wheel disc brake system. For now, the car is equipped with vented and drilled front rotors with 4-pot calipers along with a set of Bendix Premium pads - but it's not enough to allow Gary to go circuit racing with 100% assurance of personal safety. Again, he'll wait until the diff and rear brakes are sorted out before he makes the big assault on the track.

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One interesting trait of this car is its ability to pop the front ashtray out of its location whenever the right foot is mashed - I hope Gary isn't a smoker or there might be a great explosion of cigarette ash that clouds the immaculate interior! As we said, the car was bought in impeccable condition, so the only upgrades needed to compliment the already cosy cabin were embroidered Mitsubishi logos in the seats, a Momo wheel and knob and Autometer gauges for oil temperature and boost (up to 35 psi on the scale!). The factory dual cone speakers would have crumbled away long ago had they not been replaced by Gary's current tech sound system. Up front there's an Alpine CD/tuner unit that puts tunes into punchy Alpine 6x9s mounted on the rear parcel shelf.

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The creature claws its way along the road with its underside a substantial 3 inches closer to the tarmac, which benefits both the car's visual impact and its cornering capabilities. The 20-odd year old shockers and rubber bushes are no longer in service, since a set of fresh Monroe gas units and Nolathane are now hard at work. That sure made the Mitsu feel a bit more nimble on the road that's for sure.

But the car's road-going days are now limited to mainly Sunday driving because of its tyre-scrubbing locked diff and the fact that Gary wants to keep the package looking slick. But that's not to say it's just going to be pussy-footed around. Gary is dead set keen to get the car onto the race circuit and find the limits of both it and himself. The racetrack must be subliminally calling for the Astron motor to try its luck too!

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Contacts:

Turbo Tune
+61 8 8297 1030

DAT (Darlington Auto Tune)
+61 8 8277 4222

ATS (Adelaide Turbo Service)
+61 8 8377 2511

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