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Chain Smokers

With up to 287kW on tap at the wheels, these wicked RX-7s are born to burn the bags!

Words by Michael Knowling, Pix by Julian Edgar

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Seeing smoke is usually a bad thing. It can be linked to a bushfire, a burning house - or, in automotive circles, it often means a shagged engine or a cooked amplifier. But at least there's one instance where smoke is what ya wanna see - when you're pullin' a monster burnout! So next time there's smoke hanging on the horizon, don't despair - grab the video camera and head on over, coz it's probably just one of these killer 'Sevens having fun.

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Needless to say, up to 285kW (at the wheels) in a rear-drive RX-7 is one scorching recipe for a tyre-smoking machine, as the owner of this white '89 model - Clive Langley - is only too keen to demonstrate. In fact, his trusted workshop - REVS - says doughies are just about all he ever does! Oh well, there's no point having something if you ain't gonna use it!

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The owner of REVS - Jason Unkovich - together with Matty also looks after Alex Hoe's Series 6 Mazda RX-7 in our pics. It too is no ordinary Mazda, having 200-odd kW at the wheels and being the focus of Jason's extensive experience in tuning rotors. Imported second-hand from Japan, this 1995 model was delivered to Jason in (with the exception of an exhaust) standard - but very water-damaged - condition. With only 30-40,000kms on the clock, the Japanese folk had deemed the car too tough to repair and so the job was shipped off to REVS. Having been quite extensively wet, there was a sizeable job to be done and REVS replaced or rebuilt everything. They also figured that it would be in need of a full engine re-vamp - which is nothing more than a likely excuse to get it 100% rocketing if you ask us!

And that's where the similarities between these two cars begin.

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Clive's more powerful Porsche 944-shape RX-7 - although looking completely stock - was built at about the same time and packs a lot of the same basic engine building techniques as the import. Using the same 13B twin-rotor design, both engines received two-piece 3mm apex seals (from an RX-4), an extend ports and dowelled rotor housings for maximum strength. A simple formula for a reliable street-rotary - when assembled properly, that is.

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Clive's car scores its extra power purely from its higher-spec external bits. Jason recalls they fitted up a high-trim T04 turbo, shooting for maximum power - it went ultra-hard when on the boil, but when it wasn't cooking it was stone cold. So a more streetable Garrett GT30 roller bearing turbo soon went onto the custom tubular manifold, together with a Turbonetics 42mm wastegate to bleed off excess exhaust gasses. Like this, it pulls from about 3500 rpm - nice an' flexible. This compressor sucks through a conical filter hidden at the end of a 4-inch pipe. With boost set at 16 psi (thanks to a Blitz solenoid controller), a Pro Spool intercooler does it thing and the cooled induction air travels through polished mandrel bent plumbing (equipped with a custom blow-off valve) into a modified throttle body. The intake manifold is also match-ported.

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A Microtech MT8 programmable ECU (with an internal MAP sensor) is wired in and fires four 12A turbo 880cc and a stock-type twin coil ignition system. Fuel delivery is up to an in-tank Bosch K-Jetronic pump combined with a Malpassi rising rate regulator. Jason says in its current configuration, the car will start to run a little lean at about 291kW (at the wheels), so they've turned the wick down slightly to the safer 287kW figure. See it for yourself:

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And what would a hi-po turbocar be these days without a 3-inch exhaust? Clive's uses an off-the-turbo system, which splits into dual 2¾ inch pipes with glass-packed mufflers to fit the bill. The separate pipe from the Turbonetics wastegate returns gasses into the primary exhaust pipe.

The car retains its factory 5-speed gearbox, but uses a lightened flywheel and a Centerforce brass button clutch and pressure plate combo.

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Under the aluminium bonnet of the horny-looking Series 6, the emphasis is more on a responsive streeter with a bit less ultimate go. But not everything is yet complete. Jason told us that the ARC air-to-air intercooler fitted actually flows less than a Series 4 core, and that Clive's Pro Spool unit is far and away much better. The ARC unit will soon be turfed. Starting with an HKS filter, air is drawn through a 4-inch pipe into the centre of a Japanese aftermarket (either GReddy or HKS) T04S turbo, which is located on a custom 2-inch diameter tubular manifold. Pushing only 8 psi (due to injector and intercooling limitations), everything is under-stressed and the Turbonetics 42mm external wastegate (like in Clive's car) has an easy job. Even the A'PEXi blow-off valve sounds quiet-ish.

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Cunningly, the pipe from the 'gate isn't merged back into the main exhaust pipe though - rather, it's got its own short length of pipe with a hotdog muffler which vents into the atmosphere. Unlike most screamers, this set-up isn't crazily loud - but you can certainly hear when the wastegate valve is open! The rest of the system is 3 inch exhaust off the turbo, and it retains the original HKS Super Dragger muffler that arrived underneath the car.

On the intake side, the intake manifold is match-ported and the throttle body's transitional butterflies, as Jason calls them, have been removed for extra flow. When it came to selecting an engine management system, Jason says he chose the best - an Australian-designed MoTeC. This M4 version is wired in to run with a MAP sensor, is mapped for PULP fuel and enforces a rev limit of around 8200. A Malpassi regulator is utilised, while the ignition is standard. Backing the rotor is a lightened flywheel, Daikin brass button racing clutch, 900kg pressure plate and, of course, a 5-speed slick shifting 'box.

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While it hasn't quite got the goods under the bonnet to equal Clive's car, the Series 6 is most definitely the car most people would back in a traffic light grand prix. It just looks awesome. Although copping some small dents on the migration to Australia, the car came wearing ASSO 17 x 8 rims clad in 235/45 and 245/45 rubbers front and rear. Tough, tough.

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Inside is an array of audio/visual gear that's trick enough to match the gear under the lid. Alpine is the name on the CD deck, television, V12 amps and front splits, and there's also twin Orion subs pumping in the back. Other interior touches include a red carbon fibre dash and trim bits, Autometer gauges for oil pressure, water temp and revs, a GReddy boost gauge and a VDO 300km/h speedo replaces the Japanese 180 kay cop-out.

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Open the door to Clive's car and you'll also see carbon fibre on the gear knob, complimenting an Autometer oil pressure light and boost gauge and an Alpine double-DIN head unit and subwoofer speaker system. And while we said it looks stock, dedicated rotor fans will notice that the car rides a little lower than usual. That because there's Tokico adjustable dampers with RSR lowered springs, and while we're on our hands and knees, we should also mention the Hawk pads.

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REVS (Rotary Engine Vehicle Specialists)
08 8326 7700

The Boss‘s Car
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How could you expect poor Jason to work on cars such as these and not own his very own magic rotary? Well, another car that's been brought over second-hand from Japan is his luxurious Cosmo triple-rotor. The big 20B motor now makes a fair amount of grunt with its ARC intercooler and stainless steel Trust exhaust. And boy does it sound tough - heaps lumpier than the 13Bs! Mind you, it's no lightweight and the handling has also been up-spec'd to suit with Tein coil-overs and 17 inch Mazdaspeed rims wearing 215/45 and 255/40 rubber. Braking is improved with Project X pads. While, undeniably, it isn't as much of a racer as either of the 'Sevens, it's certainly a terrific cruiser - and way better than most people's company cars! Jason, you've sure got it tough...

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