First drive: Jay Leno's Volvo Polestar put to the test

AMERICAN night show host Jay Leno is believed to be the mystery buyer of Volvo S60 Polestar number one, slamming down $US300,000 for the warts-and-all prototype built by Volvo's racing partner and tuning specialist, Polestar Performance.

The Californian-based car fan and multi-millionaire asked to buy the development mule for the proposed hard-core S60 sports sedan after driving Polestar's previous effort, the one-off Volvo C30 Polestar, built by the Swedish company in 2010.

Although Polestar has declined to disclose the name of the buyer of the 374kW S60 Polestar concept that was revealed at the weekend in Sweden, Leno is known to have driven the C30 Polestar and confessed enthusiasm for Polestar in a viral internet video.

He will have to wait until later this year to collect the 300km/h Volvo, which might give Polestar engineers time to iron out some of the wrinkles of the prototype, which is a work in progress.

Clutch problems disrupted a scheduled drive day for Australian journalists at Volvo's test track in Gothenburg, Sweden, this week, firstly delaying the start of the session when a clutch had to be replaced after a heavy workload of demonstration runs by Polestar race drivers at a Swedish race meeting at the weekend, and then cutting the session short when the clutch gave out again before all the journalists had had a turn.

The session was designed to give the media, including GoAuto, a taste of the proposed Polestar-enhanced S60, on the understanding that the car was far from production ready.

Polestar is still talking with Volvo Cars about the production future of the vehicle, which is based on the 3.0-litre six-cylinder T6 S60 AWD mid-sized sedan that usually develops 224kW of power from the standard turbo six.

Polestar Performance managing director Hans Baath revealed that the engine could have delivered about 450kW, but Polestar had kept it to 374kW in the interests of driveability.

Even as it is, the huge Garret turbocharger that comes on like a hurricane as revs climb might end up being scaled back to a smaller unit that Mr Baath said would still generate 374kW but with less turbo lag.

Under the bonnet, a massive inlet duct that draws cool air from in front of the radiator feeds the air via the turbo into an equally large custom-made inlet manifold and then into the race-modified engine with reshaped cylinder heads and stronger, forged steel conrods.

The engine is mated with a Volvo six-speed manual gearbox, which is a departure from the standard car that is equipped with an automatic transmission.

Polestar has had to engineer the manual gearbox solution from scratch for the development vehicle, and clearly needs more time to come up with a production-ready clutch arrangement capable of handling a thrashing from the 575 newton metres of torque.

Behind the steering wheel, the driver can feel the extra-long clutch throw on take-off. After that, not a lot happens for a few thousand engine revs as turbo pressure builds.

From about 5000rpm, the S60 Polestar goes off like a Saturn rocket, as peak torque arrives at 5500rpm and peak power at 6500rpm.

In no time, an array of coloured lights is reflected onto the windscreen as a head-up display turns from green to yellow to red, telling the driver to change up before the rev limiter cuts in at 7100rpm.

On the short Volvo demonstration track, we spent most of the lap in third gear, carving through a series of tight-ish corners that required diligence due to a mix of cambers and the proximity of trees and embankments.

We were supposed to have two laps, but on entering the 200-metre-long straight for the first time, we went to grab fourth gear and instead found a box of neutrals as the clutch failed.

Ultimately we found third gear again and cruised back to the parking area where Volvo Polestar works race driver Robert Dahlgren confirmed the worst about the clutch condition – which he said had never been an issue in the development of the car until the previous 24 hours.

“It has caught it like the flu,” he told GoAuto.

To put it in perspective, the S60 Polstar has about 70kW more power than the S60 race car Dahlgren and his teammates drive in Sweden's premier touring car series.

It is also more powerful than three legendary German cars – the 309kW BMW M3, 331kW Audi RS5 and 336kW Mercedes-Benz C63 AMG – that will comprise its main rivals should Sweden's biggest car company give the green light to production.

Mr Baath told Australian journalists that many of the performance enhancements in the prototype had come from Volvo engineers, who had wanted to try out a number of ideas in the project.

He said several of Polestar's racing equipment suppliers had also been involved in the program, with damper specialist Ohlins coming up with three-way shock absorbers on the lowered sports suspension.

Haldex supplied a new-generation all-wheel drive system, including an electronically controlled rear limited-slip differential that, apparently, is due to appear in a future production Volvo.

However, Polestar said this AWD system also needs more work in the S60 Polestar, as it allows unwanted torque steer through the front axle.

While the mechanicals need refining, the body looks good to go. Polestar has kept the superficial enhancements subtle, with finely sculpted front mudguards made of carbon-fibre making room for the meaty 265/30 Michelin tyres on 19-inch rims.

The rear wheel arches are also extended a few millimetres, this time in steel, although Polestar went to the trouble of supplying the custom-made panels to Volvo to have them galvanised with the rest of the car ahead of assembly.

A lower front bib splitter, small boot-lip spoiler and a carbon-fibre rear diffuser were among to aerodynamic changes to keep the car planted at high speeds.

As well, the front fog lights have made way for vents to direct cooling air to the front disc brakes, which have been replaced with 380mm discs grabbed by six-piston callipers.

Inside, the S60 Polestar gets sports seats – not race-style Recaros but a variation on Volvo R Design pews in accordance with Polestar's philosophy of retaining a Volvo driving experience as close as possible to the original.

The centre console loses its raised bin in the interests of an easier gear change action, although race driver Dahlgren – doubling as chief test driver on the project – wants it to be lower still.

Hopes are high that the car will make it into limited production, not just for Europe but also Australia where Volvo’s local branch last year put a toe in the water with an S60 Polestar limited edition, that boasts – among other things – Polestar engine software enhancements to generate more power.

That car – the brainchild of Volvo Australia which showed it at last year's Australian International Motor Show – was built in two 25-car batches, with the second lot now going out to customers.

Volvo Car Australia managing director Matt Braid said the existing S60 Polestar marketed in Australia and the prospective Polestar now under development should be considered separate cars, appealing to different buyers in different price brackets.

Mr Braid said it was too early to speculate a price for a possible S60 Polestar, but it would be north of $100,000.

In the meantime, Polestar is set to build a prototype mark two, and already has parts for the project.