There are plenty of fast WRXs in Australia these days; and by 'fast', we mean running in the 12s. Interestingly, though, ninety-nine percent of the cars run those times in complete ignorance of traditional drag racing methodology; few owners have ever bothered sorting the suspension for a killer hook-up and nobody has ever thought to run an auto trans with a high stall converter. Nope. Everyone's been happy struggling along with a less-than-ideal dog box and big turbo arrangement.
That is, until Con and Vic Elfes of Sydney's C&V Performance showed how to make a Rexie make the Pro-Street boys take a gulp. Truth be known, this silver bullet (owned by C&V Performance customer Geoff Newton) isn't even a WRX - it was born a mere 1996 Impreza GX. And that's how it runs - rear drum brakes and all!
So let's examine the engine, which is making an estimated 850hp with nitrous - about three times as much as the 'supercar' STi!
The standard 1998 closed-deck crankcase is up to the job, although you'll find it has been slightly modified and equipped with 13mm studs to stop it stretching apart. The bottom-end comprises a C&V steel stroker crankshaft (which increases the swept volume to 2.3-litres), Argo conrods and JE forged pistons. Interestingly - despite the massive loads of boost stuffed into it - the static compression ratio remains at the standard Australian WRX specification of 8.0:1. Rings are Wiesco ½ millimetre oversized items.
Allowing air to be crammed into the combustion chambers are '98 STi cylinder heads, which remain standard except for a slight port job and firmer valve springs. The inlet and exhaust camshafts have also been changed, but - understandably - their specs are well guarded. The heads have been O-ringed and bite into 0-thou copper gaskets and a crankcase breather catches the engine's blow-by.
A truly monstrous turbocharger - a roller bearing Turbonetics T70 - was selected for the 800+ horsepower task; it fits toward the rear in centre of the engine bay thanks to some firewall modification. Boost pressure is currently kept to a maximum of 25 psi thanks to a Turbonetics 42mm external wastegate that's tucked almost completely out of view. Induction air is filtered by a large K&N pod filter - "there's no restriction at all through the filter" says Con - and there's no blow-off valve to be found since there's no need to back off the throttle down the quarter mile in an auto drag car.
The exhaust manifold is custom fabricated and, post-turbine, there's a monster 100mm diameter mandrel exhaust from Tuffy Exhausts. The exhaust terminates at the rear axle and there are no mufflers - so, yes, it's quite loud! Note the extensive use of thermal insulation wrap.
Initially, the engine was configured to run on methanol and without an intercooler, but when one of the big methanol injectors stuck open and bent a rod the decision was made to revert back to a more conventional C16 race fuel and intercooler combination. At 720 x 300 x 10mm the new front-mount intercooler is as big as would fit without slicing the bodywork. As WRX owners know only too well, fitting a front-mount intercooler means several miles of plumbing and a heap of bends; this was avoided by fabricating a new intake manifold with a custom 75mm throttle body. Note that the manifold has no separate plenum volume to speak of. Oh, and in order to accommodate the monster intercooler, a compact fabricated coolant radiator was necessary - but it's not like the car will get stuck in peak-hour traffic jams anymore...
You may notice the intake manifold is hung with a number of squirting devices.
Con has set the car up with a 20 horse nitrous shot to help it off the line, plus a 30 horse shot that's brought on-line once under way. The nitrous is injected a few inches prior to the throttle and the nitrous bottle lives where the back seat used to be. Also under the bonnet reside a pair of C16 custom fuel tanks complete with aviation style filler caps, twin 800hp Bosch Motorsport pumps, a SX regulator, custom rails and four hose-like Bosch 1700cc injectors. Controlling the injectors and the ignition - namely twin MSD 6AL ignition modules and M&W coils - is an EMS management system.
Obviously, an 850-odd horsepower engine is a major part of the car's 9-second performance but the driveline can also make or (literally) break it...
Con's experience in top-level competition drag racing came to the fore when he made the unusual move to an automatic transmission. Of course, it wasn't like a garden variety Ford C6 trans would do the trick but the unit from the 3.3-litre flat-six Subaru SVX appeared pretty decent. Con tracked down a bloke in the US who had experience building bulletproof Subaru trannies (which were mainly for off-road use); it arrived in Oz extensively modified and at substantial cost - and "now that the bugs have been sorted" by Northmead Autos - it has so far performed faultlessly. Gear engagement is achieved by selecting the desired ratio on a Schaffer manual transmission controller unit; push-button gearshift! The stall converter rpm is critical to get right, and is around the 4000 rpm mark. There's no trans brake since it might place too much shock load on the trans.
Note that - unlike many other fast manual gearbox Rexes - this car gets by on the standard Subaru axles and CV joints.
The suspension was altered to accommodate some serious rubber. Compact Tein coil-overs allow huge 26 x 8 x 15-inch Mickey Thompson tyres to fit in the guards without rubbing. These monster rubbers are fitted to standard WRX 15-inch fronts and Cheviot 15s at the rear - you'd hardly pick the difference front-to-rear. Some tuning of the adjustable dampers and playing with a pair of adjustable front strut top hats have made slight improvements to the car's launching characteristics. Other than that, the suspension layout remains stock; note, though, there's no rear swaybar.
Inside, there's all the equipment you'd expect to see in a competition car. A chrome-moly roll cage, gauges for engine rpm and oil pressure, Deist harnesses and Kirky alloy race seats. Aside from these seats and the aforesaid removal of the back seat, the only other weight saving measure is the fitment of an early WRX aluminium bonnet.
With only a limited number of passes under its belt, it's fair to say the car has the potential for better than its current best of 9.4 seconds at 147.6 mph. "It pulls straight the whole length of the track, the chassis feels quite settled and the engine is not overly stressed; with a bit more work it should be running in the 8s before too long" enthuses Con.
And that, folks, is a l-o-n-g way ahead of any other 'fast' WRX. We don't think it'll be long before the competition follows C&V's lead...
Contact:
C&V Performance
+61 2 9690 2000
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