CSV GTS LS7

427 Jet!

My, how the badges tell lies. To anyone else on the road, this car's hulking black presence says it's an HSV GTS, a 6.0-litre V8 powerhouse. The simple '307' on the boot lid backs that up with the kilowatt count. What they won't know is that this particular GTS has much, much more ... and its transformation hasn't actually been he work of Holden Special Vehicles.

In fact, it's taken an outsider to do the operation that so many have been waiting so long for HSV to perform. That is, take the 7.0-litre - that's 427 cubic inches to old-timers - LS7 V8 used in the mighty Chevrolet Corvette Z06, plant it between the chassis rails of a Commodore and offer it up for sale to the public. The work has been done by Peter Dichiera's Corsa Specialized Vehicles in Melbourne, an operation with no small amount of experience in turning out some wicked Commodore-based projectiles over the last 15 years or so.

We've driven the car: run it down the drag strip, through peak-hour traffic and out in the country, so can attest that the engineering, the finish and most of all the performance work beautifully. All it needs now is a new badge. For the meantime, something like CSV 427 has a nice ring about it...

It's worth cutting straight to the chase and talking about acceleration. The scene is Calder Park a couple of days after a big national drag meeting so the surface is sticky with rubber laid down by countless stages and launches. Wheels' Vbox performance gear is hooked up to the GTS, which idles a little lumpily, but otherwise has little to distinguish it from others of its ilk.

There's a six-speed automatic involved but experience on the road suggests that, even with a rubbered-up track surface, traction off the line won't be difficult, it'll be virtually non-existent. Chevrolet's figures show the LS7 grunts out 637Nm, but this example, with a better intake and exhaust system, is certainly producing even more, so what chance do a pair of standard, 20-inch Bridgestones have when that lot is unleashed in anger?

So Holden's Bosch 8.0 ESP is left to sort it out. Load up the torque converter with the left foot a little and two tonnes of heavy metal, driver and passenger stutters a bit on the software, then hooks up and catapults down the track. Manual shifting the 6L80E transmission seems to work best, but there's a few seconds of head scratching when the first-to-second gearshift hits the rev-limiter as the shift software finds it difficult to match the rapid escalation in revs. The answer is to leave it in Drive for that first shift, then change gates for manual shifting into third and fourth, using about 6500 of the available 7200rpm. Work that lot out, and each run is as repeatable and trouble free as the last.

The results? Pretty spectacular, for a home-grown sedan less than half the price of equivalent muscle from Germany. The 0-100km/h time is 4.89 seconds; the standing 400 metres takes 12.90 at a terminal speed of 187km/h. But then there are a couple of other numbers to consider. The standing 200km/h - a speed few cars are able to reach in less than 500 metres - comes up in just 14.7sec, and the 7.0-litre GTS is still hauling hard. But then there's the elasticity afforded by all that torque, too. In third gear, the 80-120km/h overtaking increment is demolished in 3.2 seconds, but in sixth (the auto's manual shift mode allows no kick-down) the same speed range is covered in just 7.3 seconds.

Earlier, we found the GTS LS7 perched on a dyno in the front corner of CSV's workshop, among hoists loaded with SS Commodores, HSV GTSs, Clubbies and Maloos all waiting their turn for some CSV action. Outside, a car park of virtually everything wearing a Holden badge and harbouring a V8 also wait for CSV attention. Customers are wandering in and out, some bloke from a nearby factory driving a VN Commodore is practising powerslides in the damp of the intersection outside. Welcome to Sunshine West.

Talk to Dichiera and it seems fitting the LS7 into the GTS's engine bay is a remarkably simple operation, including the sourcing of the engine itself from the United States, where it's available from GM catalogues for around A$22,000. The external dimensions of it and the 6.0-litre LS2 used by HSV are the same, meaning it fits onto the same engine  mounts and bolts straight onto the gearbox.

The major difference is the bigger capacity engine has a dry sump so it will fit lower in the Corvette sports car for which it was designed, and is therefore less likely to suffer oil surge on the race track. That meant CSV had to manufacture its own dry-sump system to fit a VE Commodore engine bay, and the result is the neat installation of an 8.0-litre oil tank tucked away behind the GTS's left headlight, and lots of braided hose for pumping lubricants. A simple extra bracket below the dry sump ensures the starter-motor cable clears the front cross member. Completing the 'factory' fit, CSV also adds oil pressure and temperature sensors to match HSV's row of extra gauges atop the centre of the dash.

One of the reasons everything fits neatly is because Dichiera supplies his own air intake system, which is a short snorkel high up and in front of the engine that also includes the air cleaner and mass airflow sensor. Normally, all this is included in HSV's airbox on the left of the engine bay.

Next to go is the Corvette's surprisingly conservative cast exhaust manifold, which wouldn't fit CSV's own Commodore-friendly exhaust. The replacement headers are relatively short in length, possibly to the detriment of gas flow (and therefore power output), but ensure the catalytic converters heat up quickly and do their job of removing pollutants. After that, it's a quick exit of exhaust gasses through mufflers and four no-nonsense tail pipes that eschew the GTS's machined tips and form virtually the only external recognition this car isn't totally a product of HSV's Clayton plant.

Which brings us to the power outputs. We've already covered the guts of the LS7 story comprehensively, so most of you will know the engine is hand-built by GM's High Performance Build Centre in Wixom, Michigan, with forged titanium con rods and 104.8 x 101.6mm bore dimensions to give 7008cc. Lift the red rocket covers, and there's even a plaque crediting the particular craftsman who bolted it together "with pride". In the case of the HSV GTS with the CSVLS7 numberplates, stand up, Jim Stepulkoski, whomever you may be; we salute you.

The engine has only been run in-car on a chassis dyno, so its power output at the flywheel can only be approximated. But what comes out at the rear wheels is impressive enough: there's 321kW at the treads, or around 100kW more than a standard E Series HSV can muster. So CSV is quoting what seems a conservative 400kW at 6000rpm, a very useful 93kW increase over a normal GTS, or 23kW more than the Z06 produces at 6400rpm. Peak torque is anyone's guess, but again Dichiera is quoting conservative: 660Nm, or 23Nm more than the 7.0-litre Corvette.

Other than that, modifications are surprisingly few. The engine and transmission management has been tweaked, not least to limit torque during upshifts in the lower gears to save the auto from internal demolition. But the gearbox itself, 3.27 final-drive diff, brakes, interior, exterior and yes, even badges, are the same as God and HSV intended. Suspension is also standard, apart from new Eibach springs under the rear end; they have the same rating, but are 20mm shorter for a slightly lower ride height, simply because it looks better.

And if you're getting the idea this is a one-off, never-to-be-repeated exercise, think again. If you supply the GTS (or other HSV), CSV will do the work and return a car exactly the same as this for $35,000 on top of the GTS's $76,990 retail price - fully ADRed, with a warranty and probably the maker's mobile phone number. For around $112,000, it's difficult to think of a better value performance car of any shape. Plaudits here must also go to HSV for the keen value of the GTS in the first place, which was one of the reasons Dichiera found it uneconomical to build his own CSV cars.

It also means when you plop yourself into the driver's seat there's no extra sense of occasion beyond the visual dramatics offered up by HSV - or until you turn the key. Crank the ignition and there's an initial, primal bark before revs settle down to an idle with just the faintest hint of lumpiness.

This is an eminently drivable car, thanks party to the no-brainer operation of an automatic gearbox, but also the vast reserves of torque on tap. That means the merest tickle of the throttle produces a hearty rumble, and suddenly you're doing whatever speed was imagined only seconds ago, in remarkably gentle fashion.

But there's also the impression of something angry ready to be released, and it only takes more throttle to let the beast out of its cage. Noise levels seem to triple, turning to a bellow of exhaust and a whoosh of induction, the rear-end squats and the driver is pinned back as the world comes rushing forward. On a damp surface, you're grateful the VE's traction and ESP systems work so efficiently; in the dry there's enough available traction to provide stunning acceleration even without resorting to the drag-strip starts described earlier.

But that's only part of the story. At 100km/h the GTS 427 is barely loping along at around 1700rpm in sixth gear and, truth be told, the booming of the exhaust is loud and a little tiring. Gather up a couple of lower gears and the rush is instant and unending: as well as torque that delivers a killer mid-range, the big V8 breathes so well at its top end there's little time to keep an eye on the tacho because it's the wildly increasing speed and the road ahead that commands attention.

HSV's chassis is up to the task of harnessing the horsepower and delivering poise when the road deviates from straight. Despite the engine transplant, there's virtually no shift in fore-aft weight balance (both the LS7 and 6.0-litre LS2 weigh 208kg) and so an amount of gentle understeer on turn-in can be transformed to smoking oversteer with the right gear ratio and just enough - but definitely not too much - throttle. The MRC magnetic dampers that are all part of the package provide a pliant, almost too-soft ride if needed, or a much stiffer, flatter attitude in attack mode.

There's no doubt HSV is working on its own LS7-powered car and has built at least one prototype, even if the company officially denies anything is on the production schedule. That's how big companies work, especially one that has to follow General Motors engineering and certification protocols that demand the testing and paperwork that go with a full retail operation - not to mention fitting in with a large and busy car plant like that at Elizabeth in South Australia where Holden assembles much of what HSV eventually delivers.

And by CSV's standards HSV is indeed big. If anything, this is the story of a small operator with plenty of engineering nous delivering what customers have been asking for - at an entirely realistic price. It also means if you're expecting a glitzy dealership, free cuff-links and a quarterly lifestyle magazine to go with the car, look elsewhere.

But take a look at the hugely impressive performance figures delivered by this brutal yet thoroughly cohesive Aussie muscle car, then think about how competitively priced it is in real terms, and it seems like a beguiling case of two companies working totally separately to achieve an incredible result.

Track: Calder Park, dry. Temp: 13°C Driver: Jonathan Hawley

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