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Surreal Sensation

Feel the G-forces of a 136kW at-the-wheels, 650 kilogram Puma kit-car and you'll be wearing a stretched face for six months!

Words by Michael Knowling, Pix by Julian Edgar

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I strolled on over to John Karnon who was sitting low at the helm of his automotive creation and casually popped the question - "Would you mind if I take it for a drive?". But from the expression sprouting on his face I knew this was a dead-end proposition - "or maybe you could take me for a spin", I managed to amend before he could give his negative answer. "Ahh yeah sure, I'll take you for a ride". So I made my way around to the passenger side and hiked a leg over the scuttle - being wary of the side pipe that was threatening to scar my leg. "It's a bit tight, but you'll be right once you're in" reassured John, as he pushed the starter button, bringing forth the action of the mighty SR20 turbomotor, its deep, virtually un-muffled cacophony erupting just inches to the left of me.

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Once we were on the move, a steep hill materialised in front of us and John fell victim to its allure, firmly punching his right foot hard against the firewall. Grrrrrrr - the induction and exhaust noise filled my eardrums and John had a brief dance with the steering wheel as the power was put to the pavement. The Puma's relentless thrust up the hill was nothing short of eye-popping. And as the crest of the hill and the following bend grew nearer, John just kept it pouring on. Our sheer velocity plastered one of those uncontrollable grins on my face. And before I knew what had hit me, the huge rush of air was hyperventilating me - forcing air down my lungs, stretching my cheeks and bulging my eyes! I felt like I was in one of those airforce training capsules that spins you around at Mach speeds. The SR20DET-powered Puma sure is wilder than a fairground ride from Hell!

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But the novelty factor soon subsided when I glanced over to see the speedo needle romping past 85 mph... (John still likes mph, as he's a self-confessed retro man). By this time, my mouth felt big enough to fit a watermelon and I was about to explode. But, at the last second, John punted us through the corner and gently buttoned off as we began the descent on the other side of the hill. I gestured to him the brute force of the airflow by pushing my cheeks back with my hands. "Oh yeah" he laughed, "I had a full width screen on it before these dual ones, but that created way too much turbulence". Bloody hell John, if this is somehow better than the full width screen I'll be damned!

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But John's strictly in it for the fun. Not that that was the intention at first though... John and his friend Neville Darwin set up a partnership making Lotus Super Seven type kit-cars - with a twist. Rather than opting for the common 4A-GZE powerplant, they went another step up the insane ladder and chose to fit the 650 kilogram car with a Nissan SR20DET turbo 2 litre four that's got over 200hp in standard form! Silvia and 200SX owners, you'd better be looking out! "I didn't want to go for the 4AGZE motor. The SR20 is current technology and there's also the problem of finding a RWD box to suit Toyota. Plus, of course, the Nissan is more powerful, anyway."

It was when sitting down pencilling out ideas that the design for the Puma was born - it was actually made to suit the SR motor. The Puma chassis is a multi-tube space frame of 1.6mm square tubing ERW mild steel. Half-hard alloy panels of 2.0 and 1.2mm thicknesses have been glued and riveted to the chassis to provide an extra-stiff fuselage. John, as a requirement for engineering approval, had the car torsionally tested to 8000 ft-lb per degree.

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Being a kit-car, the body is also largely made up of fibreglass. The nosecone (which John says is quite heavy), all four guards and the bonnet are all 'glass. And in case you can't see the mechanics of it in the photos, the front guards also turn in unison with the front wheels - which is one unusual sight if you're used to a conventional, fully draped car! The end result is a car longer, wider, taller and stiffer than the original Lotus Seven.

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The theme for the suspension and the brakes has been set on earlier model Ford Cortinas, because as John says, parts are widely available and very cheap. Hanging out in the breeze for everyone to perve on, the front end is independent by double fabricated ? inch wishbones and a pair of now impossible to find KYB dampers designed for a Jaguar XJ6. John modified these slightly and threaded them so that they became adjustable platforms for the 250 lb/in springs. The guys spent a lot of time on the front end so there was zero bump-steer. Its alignment is set to around 3 degrees negative camber, 4 degrees castor (non-adjustable) and 2mm toe-in. Rose joints are also used throughout.

The fitment of an early Ford Escort rack, which can later be upgraded to a quick-rack if necessary, makes steering possible via a Cortina collapsible column. And a quick-rack really is necessary says John, making reference to the snap characteristic of the LSD rear.

Cortina TC-TF solid front discs have been bolted up, and have no problems slowing this 650kg car. "They're also out in the air, which helps cool them" adds John, while the widely-spaced spokes of the 14x6 ROH Reflexes (worn in 195/60 Falkens) also allow for good airflow.

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The back end of the 2370mm wheelbase is home to a TC-TF Cortina live axle that was modified to accept four torque arms and a full width adjustable Panhard rod across the back. These arms and rods were made from 1 inch cold-drawn seamless tubing. The rear springs are rated at 150 pounds per inch and are mounted on the same type of dampers as those used at the front. Not needing to be responsible for a lot of braking force, the rear anchors situated behind the 15x7 Reflexes and 215/50 Falkens are standard Cortina TC-TF drums.

The SR20DET motor, as is usually the case in Australia these days, was bought from a Japanese import wrecker for a song. However, it came minus the electrical components required to make it run - which is where Adelaide's RPM Performance Centre came in. They wired-in a programmable Microtech MT-8 ECU to fire a set of direct-fire coils and Nissan's stock SR injectors.

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The exhaust is minimalist to say the least, with a 2? inch pipe off the turbo leading into a high flow cat and a gentle curve just in front of the rear guard - and that's it! That curved piece of stainless encompassing the pipe towards its end is merely a fake muffler that doubles as a heat shield for human legs - it doesn't mute the bark of the SR at all. A Bosch blow-off valve and an air-to-air intercooler from an RX7 were also plumbed into the works, the core sitting right up before the engine radiator where it can work best. Another re-routing of the intake system includes the moves needed to fit the VN Commodore air cleaner, which is contained at the back of the engine bay. RPM fitted up a hi/lo boost switch to give John a little extra power for when the "need" arises. At its conservative maximum of 11 psi, the car pushed out 136kW at the wheels on their dyno. And need we remind you - this car weighs just 650 kilograms! John guesses that this power-to-weight combo should see the Puma propel itself into the high 12s - traction permitting. John would like to officially thank RPM, who got this job done on time and under budget. Heading rearward, a standard Nissan 5-speed gearbox (fitted with a short-throw shifter) is bolted to the bum of the SR, and transfers torque down a modified Cortina tailshaft to the live-axle Cortina 4 pinion 3.7:1 LSD.

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To make the car an absolute attention grabber, the interior was also colour-coded in bright colours to suit the body. Across the dash are gauges for rpm, mph, volts, fuel level, fuel pressure, oil temperature and pressure and water temp. Space for the driver's feet has been improved by fitting the engine into the chassis about two inches to the left, just like Ford did to clear the brake master cylinder in the first twin-cam Cosworth-Escort.

After John and Neville had pieced together Puma Number One in December '98, they set off seeking all the relevant RTA approval and legal stuff. But much to their angst, they discovered that if they were to get public liability insurance (and it'd be like playing roulette not to) it would take a fee of A$12,000. Not just as a one-off payment, but annually! Financially, it just wasn't going to be worth all the effort.

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But consumed with love for the cars, they'll build a couple more exclusively for their own use. Namely, one car for Neville and another revised one for John. Revised? John says there are a couple of things he'd like to do differently when he builds another car. This includes making the scuttle taller to give the car a different bonnet line, and the deletion of some more kilos. At the end of the day, "I really enjoy building them" he says. "It's a fun car, and I like to drive it whenever the weather's fine and I'm feeling silly". It's even made a four day trek to Alice Springs and Ayres Rock in the centre of Australia, in convoy with the Cobra car club!

Now, I'd hate to be the one in the passenger's seat on that trip. You'd doubly have to make sure you kept your mouth closed, or you might end up stretched cheeks and swallowing a big dune-bug!


Puma cars - John Karnon
+61 8 8370 5275

RPM Performance Centre
+61 8 8277 2266

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