Holden's humble Gemini has never been the sort of car to make you quake in your boots while you're sitting at a set of traffic lights. The 1.6 litre four - even in a "warm" state of tune - won't push it into the lead against many other cars. ChipTorque's young Matthew Spry knows this only too well - which is exactly why he's gone out and built this outrageously fast exception to the normal Gemini rule! Matthew has always had Geminis coz, he says, they're easy to work on and - above all - "they piss people off". Yes sir, nothing would be more humiliating than getting dusted by a Gemini - let alone totally annihilated!
So let's establish one thing now - this TG model Gemini is ultra, ultra quick. In fact, it's already broken into the 10s with a blinding 10.66 at 127 mph - and Matthew tells us it can go faster! But it's not only a zero-to-hero machine; it has also taken top spot in the Summernats 12 Horsepower Heros turbo four category. The winning figure? 265hp at the rear wheels on a lazy 13.5 psi! But put in a little more pressure and it can go to 355 horses... (yes, we're still talking about a Gemini here!)
That relatively low boost figure is particularly relevant, because it proves one thing - this is not an over-revved, over-boosted grenade. Matthew had a big hunger for extra cubes, and (after trying a 2 litre Piazza turbo motor) went for the grunt of a 4ZE1 2.6-litre Isuzu. You know, like they use in those rough-and-tough Rodeo commercials... Matthew explained that all the conversion really took was to file away a bit of metal on the firewall for some added dizzy clearance. Simple. But to help keep the larger capacity engine cool, a three-core LJ Torana radiator and a 12-inch thermo fan was included as well.
The engine is far from standard. Inside it - starting from the top - is a ported and polished head, cc'd combustion chambers, a custom Sure Cam bumpstick, Performance springs and stainless valves. An adjustable top cam gear has also been hauled into the show for fine tuning. The bottom end comprises 94mm Mahle forged and HPC'd slugs with gapless rings (delivering a 9.0:1 compression ratio) and a set of durable Argo steel rods. Those rods were an absolute necessity considering the amount of torque they're being asked to handle.
Encouraging the 4ZC1 on its way to 355 rear wheel horsepower is a Garrett T3 turbocharger with a T04 front cover. This is located to the side of the crossflow head via a stainless steel tubular exhaust manifold that was fabricated by "Stuart". Off the back of the turbo, however, is an exhaust system that's the work of Hinterland Exhaust. This uses a 3½-inch dump and a 3-inch main pipe, and connects up a 3-inch high flow cat converter, and a Hooker Aero Chamber muffler.
The intake to the turbo is constructed from a 4-inch flexible duct with a K&N pod filter at the opposite end. Air gets pushed from the compressor and enters a nice an' big cut-down truck air-to-air intercooler. A Goyen blow-off valve is installed too.
The make-up of the post-turbo intake is no surprise given Matthew's job at ChipTorque. Under the bonnet lies a 65mm Commodore throttle body that's bolted to the reverse side of the standard Rodeo manifold. Fuel (premium unleaded) is fired directly into the engine by a set of four Mazda 13B turbo injectors, which are fed by a Bosch Motorsport fuel pump running 5/16-inch lines. Ignition is left up to the combination of a V8 Commodore single coil and igniter module, Magnecore leads and NGK plugs.
And whose job is it to conduct the fuel and ignition show in perfect harmony? None other than a Delco system - just like those fitted to a VN-onward Commodore. A 3-Bar MAP sensor is wired in to this box of tricks, and a custom ChipTorque software re-write has also been performed. Interestingly, the Delco system is being used to control everything - including boost and knock control.
Behind the big cube slogger is a standard clutch with a big one tonne pressure plate. The gearbox of this Gemini brings up an interesting point. Because of the turbo engine's huge power and torque, the standard 4-speed gearboxes last a very minimal amount of time. How minimal? Well, Matthew's chewed through about
ten 'boxes in the last year! He even buys them in bulk - three for a hundred bucks! A Trimatic auto is on the cards to fix the annoying situation. Amazingly, the car also retains its standard diff. Spinning its limited slip 3.9:1 centre and 28 spline axles, it holds together extremely well considering.
We were about to cringe - half-expecting Matthew to tell us the standard brakes were fitted as well. Luckily, they aren't. The fronts have been up-spec'd considerably with a pair of Piazza ventilated discs with QFM pads (like the rear). The suspension too has been revised and brought nearer the performance of the engine, thanks to lowered King springs and Koni shocks.
Outside, Matt Evans Smash Repairs have brought the bodywork plumb up to scratch. The only mods are the clearanced wheel arches - the rest is pure Holden design. With the body straight and cancer-free, it was then treated to a splash in metallic green paint with a trace of gold pearl to add effect. The engine bay was also detailed - important given that the engine is such an important aspect of this car.
The interior has copped a full revamp since it left the Holden assembly plant - however the emphasis is still on "light-weight". There's no console or anything like that, but what is there is good stuff. Like the Cobra Sprint seats, the sporty wheel, Alpine CD/tuner and splits and the ever-active Autometer 30 psi boost gauge. Matthew values his life, so he also has installed a Bond alloy half-cage and Dominion 4-point harnesses. A 10-second Gemini, we'd imagine, isn't going to be the most controllable vehicle on the street!
Of course, that stuff's all inside the cabin - but we wanted to know what's going on inside Matthew's head. What are his future plans for the car? First of all, there's that Trimatic trans he's got in the pipeline, plus a whole host of other things he wants to do. Namely, a Garrett ball-bearing turbo and external wastegate, a 3½ inch system, nitrous, sequential Delco management and a revised intake with bell mouths and another set of injectors.
Gor, blimey. What's Matthew's next project gonna be - an 8-second Datsun 1200 ute? Hmm, or maybe that has already been done...
Thanks to -
Sam Nemeth, Adam, Damien, Mick, Donna and Lachlan from ChipTorque, and Craig and Matt from Matt Evans Smash Repair.
Contact:
ChipTorque
+61 7 5596 4204
www.chiptorque.com.au
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