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Behind the beast:: An in-depth look at the Corvette ZR1-powered 2017 HSV GTSR W1

You already know it’s limited to 300 units. You already know it’s $169,990 (before on-road costs). And you already know it’s powered by the much-hyped LS9 engine out of the Chevrolet Corvette ZR1. Now, though, it’s time to go in-depth to find out what makes the 2017 HSV GTSR W1 as special as it is, and will forever be…


In case you missed it, you can read and watch our 2017 HSV GTSR W1 Phillip Island pre-production mule quick drive review here, and find out more about the entire 2017 HSV range here.

 

The Program

The HSV GTSR W1 was internally codenamed ‘P860HP’. Why? As HSV managing director Tim Jackson told CarAdvice, the regular GTSR was known as the ‘P860’, with the W1 being the high performance (HP) version of that car.

What does it mean? Get this: “[The codename] doesn’t relate to anything,” Jackson said. “It’s completely random.”

Although HSV had intentionally been holding off reviving the iconic GTSR nameplate, according to Jackson – MD at HSV since 2009 – the decision to bring it back for the Zeta platform send-off happened relatively early in the program.

“When we start a program we allocate a number to it, so we don’t allocate the brand or the solution, but I think we knew we felt ‘GTSR’ fitted the program probably 18 months to two years ago.

“We knew it sat comfortably for us in terms of against the program. So, we’ve known it for a while, but actually locking it in and actually confirming it, probably only [happened] six months ago.”

Despite HSV revealing it normally allocates up to three years for a program’s development, with GM’s LS9 engine only being confirmed and secured in the last six months of the program, development of the GTSR W1 had to be compressed into nearer to two-and-a-half years.

As for total investment in HSV’s final Zeta platform range, Jackson said, “I won’t give you the specific investment number, but it’s a high single-digit million-dollar investment, closer to $10 million than $5 million.”

“Typically when we’re investing this type of money, we’re expecting a three- or four-year time horizon to get a return [not the 10 or 11 months the Zeta platform has left to run]. But we know, it’s a moment in time, it’s an opportunity, and it’s an expectation for our customers that we deliver something special.”

From the outset, HSV’s goal for the GTSR W1 was to develop not only the best-ever HSV, but, in its words, “The ultimate Australian-made driver’s car.”

Limited to 300 cars in total (approximately), production of the GTSR W1 is due to begin on April 10, and wrap up at the end of September this year. And, as Jackson makes well and truly clear, “It is fair to say that without the support of Holden and GM, this program wouldn’t have happened.”

“It happened relatively quickly, and it needed a lot of support from Holden/GM to make it happen, so we do give them a note of thanks for that support.”

 

The Engineering

If you want to know even more about what went on behind the scenes of the W1 program, speak to those at the coalface - people like HSV's engineering director Joel Stoddart.

“So many passionate people at HSV wanted to make sure this car didn’t go out with a whimper – that was our first objective,” Stoddart revealed.

As the original VS Commodore-based HSV GTSR featured carbon-fibre – used on its wheel inserts, side skirt accents, badging, and rear wing – HSV made the decision that the new GTSR W1 would follow suit. That, plus, as Stoddart admitted, “It looks really cool.”

As such, the W1 features carbon-fibre front fender vents, a carbon-fibre upper plane for its ‘Aeroflow’ rear spoiler, and a carbon-fibre air box, with all carbon-fibre components sourced from Italian-based carbon-fibre experts, BMC.

Although the W1’s outrageous outputs and impressive performance figures are hard to ignore, it’s the engineering that’s gone into making the damn thing happen that’s truly awe inspiring.

As Stoddart explains, “When we wanted to do this program, we decided LS9 was the engine – it worked in Zeta platform, there was no physical reason why we couldn’t make this happen, but we actually had to secure the engines because they’d gone out of production.

“So, we had to make a few phone calls and spend a bit of time in the US meeting people, got into the warehouse and we found the holy grail – we found these engines that GM had sort of stockpiled for the next 10 years – and we convinced them to give us enough to make this car and this program viable.”

With time being of the essence, engine calibration and Euro-5 certification programs had to be significantly compressed. And, as Stoddart tells us, these were only achieved with help and support from GM and Holden.

“Calibration/certification programs can take years, but with this one, we didn’t get a second swing at it. Noise drive-by was another big challenge for us. You know, we struggle with LSA, [so] how are we going to go with this bigger, meaner, nastier car, getting it through noise drive-by?

“I could probably talk for days and days on the program, but I think they are some significant challenges and hurdles that we overcame getting this car into production.”

Hurdles indeed. Plugging an LS9 engine into a Commodore might sounds straightforward enough, but think again.

The W1’s carbon-fibre airbox had to be an OTR setup (over the radiator) as the engine runs a dry sump system, and the system’s upper oil separator effectively occupies the space traditionally occupied by an airbox.

Apart from looking “really cool”, carbon-fibre was deemed the only material that could “survive” at the airbox’s necessary minimum thickness of around 2.5mm.

Due to packaging restrictions, engineers were also forced to rotate the radiator back six degrees, while a new lower air intake was added specifically to provide sufficient airflow for the W1’s transmission cooler.

As the W1 doesn’t employ the same hydraulic power-steering pump as the left-hand-drive Chevrolet Corvette ZR1 – which comes included as part of the LS9 crate motor – HSV had to come up with a new front-end accessory drive (FEAD) configuration specific to this single application.

Some ZR1 parts didn’t require core engineering changes, such as the dry sump system’s upper oil separator, lower pick-up and return, and two-stage oil pump. However, a W1-specific centre, designed in-house by HSV, was required to fit the LS9 into the top-shelf GTSR – helping the entire dry sump system total 9.93 litres in capacity in the process.

Of course, the Corvette ZR1’s exhaust wouldn’t fit the W1, so, again, HSV designed a new one in-house.

Featuring an integrated 2.5-inch catalytic converter – an HSV first, required to prevent the exhaust manifold fouling on the dry sump centre – the four-into-two-into-one system is ceramic-coated stainless steel.

“I’m always impressed by the creativity in our [engineering] guys to find solutions to problems,” Jackson told CarAdvice. “Somehow they seem to find a way.”

 

The Hardware

A hand-built unit that takes approximately five hours to be assembled, all GenIV LS9 engines were assembled at GM’s Performance Build Centre in Wixom, Michigan.

A supercharged 6162cc (376 cubic-inch) engine based on the LS3, the LS9 - in ZR1-guise anyway - runs a compression ratio of 9.1:1.

Costing around $35,000 Aussie dollars per engine (plus taxes), the LS9 features a sixth-generation Eaton four-lobe Roots-type supercharger, an aluminium block, unique camshaft, forged-titanium conrods, titanium inlet valves, hollow-stem exhaust valves, cast iron cylinder liners, and forged-aluminium pistons with in-block oil spray cooling oil jets, as well as the dry sump oil system mentioned earlier.

HSV says it opted for LS9 for the W1 not only because there was no physical reason not to, but importantly, because in 435kW/740Nm GTSR-trim, the supercharged 6.2-litre LSA is approaching its limits - and the limits of the transmission it’s bolted up to.

For context, the LS9 – equipped with a specific air filter and 87mm throttle body – claims 2.3 litres of air per revolution (L/rev), the LSA 1.9L/rev. The LS9 also has a maximum rpm of 6600rpm, the LSA maxing out at 6200rpm.

With official power and torque figures recently confirmed by HSV, we can tell you the W1 develops 474kW at 6500rpm and 815Nm at 3900rpm – 2kW and 4Nm off the outputs of the 476kW/819Nm Chevrolet Corvette ZR1 that ceased production in 2013.

HSV has equipped the LS9 with a nine-plate water-to-oil cooling system, uprated from the seven-plate stacked-plate unit used in the LSA.

A larger heat-exchanger intercooler – offering a 49 per cent increase in core volume over that used for the LSA – has also been added to aid cooling efficiency, along with an additional high-flow water pump and an upgraded dual-brick charge-air intercooler, instead of the LSA’s single-brick item. HSV says the improved setup sees charge air temperatures cooled by up to 60 degrees Celsius.

Performed at HSV’s Clayton facility in Victoria, the GTSR W1’s engine out/engine in production requirement is a rare process not seen since the $155,500, 375kW/640Nm 7.0-litre LS7-powered W427 back in 2008 – of which only 136 were ever made.

 

The Transmission

With the LS9 engine confirmed, HSV was presented with its next challenge: getting all that power and torque to the road.

“We got the engine, and we thought we’d got this program over the line,” says HSV engineering director Joel Stoddart.

“And then we figured out that we needed a transmission that could handle over 800Nm of torque, and there were none available in TR6060 [to fit] our Zeta platform.

“We knew that the gear set was around with Corvette, but we couldn’t actually apply it in our vehicle, so there was a lot of work put in. I said to our program manager a year ago, ‘This could really kill the program’. [But now] it looks, smells, feels the same as the old transmission, but we put a lot of work in.”

The solution came in the form of an MH3-specification Tremec TR6060 – a close-ratio six-speed manual gearbox with triple synchros, rated to 850Nm.

As the team at HSV found previously with a number of other components, though, things weren’t as simple as first thought, with the GTSR W1 requiring a new application-specific input shaft, developed with help and support from Tremec, GM, and Holden.

With the transmission partnered to a 260mm hi-performance lightweight ZF SACHS twin-plate clutch – the LSA uses a 240mm unit – and a solid or single-mass flywheel, the combination forced engineers to have to modify the bellhousing of the W1’s unique gearbox, while also having to extend the new input shaft’s spline.

 

The Suspension

You can’t just throw a new monster engine into a car and expect it to handle it, so, as Stoddart says, “Putting the right chassis under this car, getting all of that performance to the ground, was a really important challenge for us.”

As such, HSV decided from the outset that the goal was to implement the most race-like suspension system they could, without comprising noise isolation or overall refinement.

The answer? Ditch HSV’s own Magnetic Ride Control (MRC) system used in the GTSR sedan, and combine the car’s original suspension mounting system with a track-focussed package from South Australia-based SupaShock, a partner of HSV and Walkinshaw Racing’s Supercars operation.

Comprising SupaShock dampers, upside-down front mono-tube struts with rebound springs, linear-style damper pistons, and coil-over front springs and conical rears – featuring spring rates 2.2 and 2.0 times stiffer, respectively, than those of a standard HSV GTS – even Stoddart admits the setup is approaching that of a Supercar ready to tackle a street circuit.

Designed with ultimate performance in mind, the W1’s firmer and lower suspension (5mm lower than rest of the GTSR range) is also calibrated to accommodate the flagship model’s 9kg of extra heft.

 

The Brakes

Despite the mild increase in weight, the 1895kg (unladen) W1 sports the same brakes as the GTSR Maloo and GTSR sedan.

That said, given these are larger than the 394mm front, 380mm rear carbon-ceramic Brembos fitted to the albeit lighter Corvette ZR1 – closer to 1521kg thanks to numerous carbon-fibre and polycarbonate elements – we reckon they’re likely to hold up alright.

Teaming six-piston single-piece mono-block AP Racing calipers (made of forged 6061 aluminium) all around with 410mm fully-floating cross-drilled two-piece rotors up front and 372mm cross-drilled items out back, HSV says the GTSR package not only increases pad area by 25 per cent, but helps reduce weight, compared with the GTS’s already-not-insignificant AP Racing setup, by 10 per cent.

Bigger than those on the ZR1, for context, the GTSR brakes also trump those used on the last iteration of Car of the Future-based Supercars – out-and-out race cars equipped with six-piston AP Racing calipers and 395mm discs up front, and four-piston AP calipers and 355mm discs at the rear.

Additional help comes from Ferodo brake pads, while race-inspired ‘S-vane’ brake disc cooling technology is aimed at keeping brake temperatures in check.

 

The Wheels and Tyres

For reference, the original 215kW/475Nm 5.7-litre naturally-aspirated V8-powered VS Commodore-based 1996 HSV GTSR rode on 17-inch alloy wheels and 235/45 Bridgestone Expedia “high-performance tyres”. It’s 2017, though, and now the new GTSR W1 rides on some genuinely massive – and expensive – rolling stock.

Up front the W1 gets 20x9-inch forged-alloy ‘SV Panorama’ wheels, with 20x10-inch items on the rear – half an inch wider, front and rear, than the GTS’s 20x8.5s and 20x9.5s.

Giving the W1 some impressive front-end bite and response, HSV’s engineers also managed to incorporate a three-degree negative offset change into the W1’s front wheels compared with the GTS.

The real ‘trick’ to making the GTSR W1 a legitimate road and track weapon, however, comes from its slightly mental Pirelli P Zero Trofeo R tyres.

Measuring 265mm-wide at the front and 295mm-wide at the rear, they are 35-aspect up front and 30-aspect out back. Not for messing about, the super-aggressive R-compound Italian rubber retails for around $1400 a pair, or $2800 a set. Ouch.

Overall, as a result of the new engine, new brakes, new tyres, and new suspension, the W1’s electronic stability control (ESC) system, too, has benefited from a complete recalibration.

 

The Result

We’re not always number-driven here at CarAdvice, but these are worth a look.

Although HSV is still stipulating these figures as “preliminary”, let’s just say we’re confident they’ll be near the mark.

  • 0-100km/h in 4.2 seconds
  • 0-60mph (96.6km/h) in 4.0 seconds
  • 0-400m in 12.1 seconds

Thanks to the close-ratio gearbox’s tall first gear, HSV says the W1 will hit 98.5km/h in first gear, with 80-120km/h achieved in 2.16 seconds in second gear, and in 5.2 seconds in fifth gear.

Sadly, despite the W1’s theoretical potential to reach approximately 293km/h in sixth gear at 6600rpm, as with all VFII-based products, the ‘Big Dog’ GTSR is still speed limited to 250km/h.

With none other than Supercars driver Warren Luff at the wheel, HSV says the W1 has already lapped Victoria’s 3.0-kilometre Winton Motor Raceway in 1.33:20 – 4.4 seconds faster than HSV’s 1:37.60 GTS record. A good time, it’s still 13.5 seconds off the 1:19.70 Supercars lap record set by Fabian Coulthard in an FGX Ford Falcon in 2016 (just teasing, HSV).

And for those thinking of taking their GTSR W1 to the track themselves, HSV’s top engineering brass say, ‘go nuts’.

Although neither the GTSR nor GTSR W1 feature the same ‘GM Level 3 Track Capable’ rating as the recently reviewed 2017 Holden Commodore Motorsport, Magnum and Director trio, Joel Stoddart says enthusiasts needn’t worry.

“The test mule you drove today, that’s completed two full days at Winton, a week up at Hidden Valley in hot weather, and of course down here at Phillip Island for final validation – and that’s on the same car.

“That car’s done four track days on the same engine, same components, etc. So, [on top of the upgraded cooling], we do make sure these cars are capable on the track, because it’s where people will test them, and it’s a good measure of their performance.”

 

The Body

Looking the part, with its tough stance, the W1 wears all-new front and rear bumpers, a new front splitter, new horizontal front fender vents, and new front fenders that are 12mm wider per side than those of the GTS.

Made of polypropylene, not aluminium like on the GTS, wider fenders have been something of an inside secret at HSV for some time, with the company’s chief designer, Julian Quincey, asking for them since HSV released the VZ-based Coupe 4 in 2004.

At the back, a new carbon-fibre-topped ‘Aeroflow’ rear spoiler is joined by a new rear diffuser, and new chrome-finished ‘diamond-shaped’ outlets for the W1’s re-calibrated bi-modal exhaust.

Never satisfied, engineering head Stoddart tells us he still wanted HSV to say yes to equipping the W1 with a wider rear end to accommodate the rear wheel and tyre package he really wanted – the ZR1’s 20x12-inch rear wheel, wrapped in a 335mm-wide, 25-aspect tyre – but it couldn’t physically be done… this time, anyway.

 

The Interior

You can’t release a car like the GTSR W1 without making a few ‘necessary’ improvements to its cabin.

Fortunately, HSV thought the same. That means the lucky few who will ever get to sit in the damn thing will enjoy some phenomenally comfortable and supportive new ‘Podium’ seats, fully upholstered in diamond-quilted Alcantara.

Accompanied by ‘W1’-branded headrests, the seats are complemented by an Alcantara-wrapped sports-profile multi-function steering wheel, an Alcantara-wrapped gear lever, and a variety of ‘W1’ branded items, including the sill plates, an ID plate, and the start-up screen for HSV’s Enhanced Driver Interface (EDI) system.

 

The End

Indeed. With Holden confirming production of the VFII Holden Commodore is to wrap up on October 20, the end for the tried and tested Zeta platform is well and truly nigh.

HSV says approximately 300 GTSR W1s will be built, spread across 56 Australian dealers and six Kiwi ones. That said, HSV will be keeping a small number for their own purposes and requirements, with this tipped to be up to five cars.

Currently, HSV says it’s looking at “in excess of 800 orders” for the GTSR, however, this is said to encompass interest in the GTSR Maloo, GTSR sedan, and of course, the GTSR W1.

Additionally, HSV has suggested it may very well hold a small number of cars – likely three to four – for frequent HSV buyers who might miss out on the initial allocation of W1s. The idea then being for those known owners to have a second chance of securing one of these very special vehicles via a raffle.

As for some final thoughts, we’ll leave that to HSV managing director Tim Jackson.

“I think there’s a sense of pride we’ve really achieved something here. I’m proud that we’ve delivered the best product we’ve ever done, and I’m grateful for the support we’ve received from Holden and GM and all around the place. If every time you do a product, you’re trying to do a better one, and do the best one, I’m convinced we’ve done it on this one.

“And, I guess from a personal point of view, we’ve pushed the boundaries in terms of what we typically do – you wouldn’t typically adopt this level of change on a program this short. With the constraints we have and the tools that we have, I think we’ve delivered.”


Podcast

Listen to the CarAdvice team discuss the HSV GTSR W1 below, and catch more like this at caradvice.com/podcast.

Click on the Photos tab for more exclusive 2017 HSV GTSR W1 images by Tom Fraser.

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