Reared science
Wheels Magazine 
August, 2002
Australia versus England, Round One. Rear-drive V8 sedan division. Hang on a minute. What have they got that could possibly take on our champ, the 300kW C4B-engined HSV, a heavy hitting, high priced four-door with a string of knockouts scored in a two-year career? Then it's time you were introduced to England's newest hero...
Meet the S-Type R, the $162,000 sedan with more power than any previous series production Jaguar. Where the supercharged 4.0-litre AJ-V8 used in the earlier XJR and XKR delivered 276kW, the R's enlarged engine ups the number to 298kW.
Now you understand why this is the contest that had to happen. The Holden and the Jaguar have more in common than you might at first think. Both are the high-performance glamour models that top off ranges that begin with much less expensive six-cylinder models. Both are products of small divisions of those car-industry giants, General Motors and Ford. Age and family history, too, are similar. While the S-Type range was launched back in 1998, there hasn't until now been a truly hot version of the middle-size Jaguar. The supercharged R was only added as part of the model's extensive mid-life update this year. The HSV's basics are a year older, dating back to the 1997 VT Commodore. But it wasn't until 2000 that the 300kW engine was introduced.
Enough of the past. Time to look in some detail at how Jaguar created the S-Type R. First, they enlarged their V8 with a new crankshaft, used in the naturally aspirated version as well as the R's supercharged engine. Stroke increases just 4.3mm, from 86.0mm to 90.3mm. The new crank seems to have served as a good excuse for the Jaguar engine department to perform a thorough renovation of the AJ-V8. The basics were sound, they thought, thanks to the inherent rigidity of the aluminium block and heads assembly. The engineer's efforts were focused on making the engine sweeter and smarter. Smoothness, quietness, and efficiency were the prime objectives. The lubrication, engine management, and exhaust systems were revised. The heads were modified (with compression ratio of the naturally aspirated version lifted from 10.5 to 11.0, while the supercharged variant makes a very modest rise from 9.0 to 9.1), a quieter chain found to drive the engine's four camshafts, and a quicker acting vane-type mechanism installed on the engine's variable camshaft timing system.
With the supercharged engine, the list goes on. Additional developments exclusive to it include forged pistons, with soothing oil jets squirting at their hot little bottoms, and a special twin-pump fuel-delivery system. While the belt-drive Eaton supercharger nestled deep in the engine's cleavage remains the same, a smaller pulley increases its speed by five per cent to supply the enlarged engine with similar boost to the 0.8 bar of the old 4.0-litre. Jaguar's engineers may have stuck with the supercharger they know so well, but they altered just about everything else in the inlet system. The airbox now has dual inlets, for instance. Attention was paid to improving airflow both into and out of the supercharger. Finally, a pair of new high fin-density, liquid-air intercoolers have been specified.
It's worth lifting the clip-on plastic modesty cover off the top of the Jaguar's engine, because the supercharged V8 looks great in the nude. The cast-aluminium intercooler inlet tanks, each with the word 'Supercharged' standing proud, dominate the view. As for the supercharger itself, it's almost completely concealed, hidden beneath the fat trunk that delivers filtered air to the Eaton's rear inlet and the flanking intercoolers that receive pressurised air from the supercharger's side outlets. Only the supercharger's Pinocchio-length nose is easily visible.
What don't you already know about the C4B of the SV300? Not much, probably. In the two years or so since the 300kW 5.7-litre V8 was first unleashed in the VT II-based GTS, there has been no shortage of words describing and analysing HSV's top engine.
Here, for those who haven't been paying attention, are the salient points again. Beneath the 'HSV'-embossed red plastic panels is an engine that's shipped from the US for our consumption. The story begins with a Gen III V8 being manufactured in a General Motors plant in Michigan. The C4B-to-be is then shipped east to Callaway, in Connecticut, for modification. While the crank, rods, and pistons aren't disturbed, the Callaway crew do a major job on the all-aluminium engine's heads. The combustion chamber and ports cop a good machining, stainless steel valves and stronger valve springs with titanium retainers are installed. A camshaft with extra lift goes in somewhere along the line. HSV doesn't like it if you say it's an off-the-shelf item. And they have a point. Up to a point.
In truth, the C4B is a collaborative effort. Callaway supplies considerable expertise in mental hardware for Gen III V8s, HSV brings considerable Australia-specific engine calibration know-how to the project. While it's easy to point out what's been done by Callaway, the HSV contribution is basically a bunch of bytes that resides in a computer that lives who knows where. You can pick up a hot camshaft, feel its heft, look at its lumps, understand what it does. Try that with your clever engine-management algorithms. You see the problem.
But you can also feel the effect. At idle, any C4B-engined HSV - including this SV300 - rocks gently side-to-side on its suspension as the V8 occasionally stumbles, but from the moment the shoe sole presses pedal it's a very polished performer. Smooth and tractable just above idle, delightfully thrusty in the middle, and brutally bestial beyond.
In contrast, the Jaguar's supercharged AJ-V8 is utterly civilised at idle, giving no hint of what is to come. But press the S-Type R's accelerator all the way to the floor and things happen. Almost immediately you're surfing a tsunami of torque. The trademark supercharger whine grows louder and louder, the scenery comes at you faster and faster.
The supercharged AJ-V8 is one of the few engines capable of making a C4B feel underendowed. Where the HSV claims 510Nm at 4800rpm, the Jaguar figure is 553Nm at 3500rpm. Thanks to the magic of supercharging, more than 80 per cent of this figure is available anywhere between 1500rpm and the rev limiter.
Luckily, the Jaguar's transmission exerts a civilising influence. The revamped S-Type range is only the second car in the world, after BMW's new 7 Series, to employ ZF's six-speed automatic. The German transmission and steering specialist has made a very smart auto. Where the five-speed auto previously used in the S-Type contained 660 parts, the new ZF, thanks to an innovative planetary-gear design, has only 470. As well as delivering a nice, wide ratio spread, the six-speeder is capable of handling even more than the supercharged Jaguar engine can dish out. Like 320kW and 600Nm.
The ZF is wonderfully suave, swiftly shifting shocklessly down through several gears when kickdown is invoked, and sweetly slurring wide-open-throttle upchanges. The only thing wrong with it, really, is all down to Jaguar. While other manufacturers seem to like the idea of adding pseudo-manual modes (always with names ending in 'tronic') to their automatics, Jaguar persists with its J-gate idea. When in D, push the selector lever to the left to access the parallel path. Here, on the 'manual' side, 5, 4, 3, and 2 are your options. The problem is that the détents between them aren't very definite. In the heat of the moment it's easy to go one gear further than intended. It's best to just leave the lever in D. The ZF does an excellent job of picking gears when left to itself.
The combination of monster engine and master transmission makes extracting maximum performance from the S-Type R incredibly simple. Engage D, release brake, press accelerator pedal to floor, wait a while. That's it. You could safely schedule a 14.2sec chat while running standing-start 400-metre times in this car. Reaching 100km/h takes 5.9sec. This is 0.3sec more than Jaguar's claim. We, remember, always run performance figures with driver and passenger. They, we strongly suspect, do not.
Regular readers will know that a C4B-engined HSV will trump the S-Type R's figures, despite being harder to launch. The SV300 delivers the kind of numbers I know to expect. For the record: 0-100km/h in 5.8sec, 0-400m in 14.0sec. Not only slightly quicker, but a very, very different experience. Instead of calm, there's frantic action. Beep, bam, bellow.
The HSV's visible and audible shift indicator is a useful aid in the pursuit of ultimate performance. Watch for it, listen for it. See it, hear it, then punch into the next gear, aiming for speed rather than smoothness and ignoring the audible agony of 510Nm trying to twist the car's beefy body. Slam the throttle wide open and hear the rage in the engine bay begin all over again.
The HSV is melodramatic, the Jaguar is undramatic. This applies on the road, as well as on the strip. But there's one difference. Get among the double lines and yellow advisory signs, and it's the S-Type R that is definitely the fastest. And so it should be...
Jaguar extensively revised the S-Type's front suspension for the car's mid-life update, creating in the process a beautiful set of components. New, two-piece, forged-aluminium lower A-arms. New upper A-arms, again in forged aluminium. New, stiffer, squeeze-cast aluminium uprights. Although the pieces are very pretty engineering, they weren't designed for good looks. The engineers wanted to minimise track and camber change, at the same time as increasing the suspension's anti-dive characteristic.
Alterations to the double-A-arm rear suspension were relatively minimal: small changes to subframe, brackets, and bushings; new toe-control link; roll centre lowered to work in harmony with the new front suspension; as at the front, new, large-diameter tubular anti-roll bar; new, stronger lower-control arms to cope with the torque of the R engine.
Pure class, front and rear. But there's more. The S-Type R is equipped with Jaguar's CATS (for Computer Active Technology Suspension, if you're interested) dampers and stiffer springs. Each damper can be electronically toggled between a soft normal setting and a firmer setting in milliseconds. The system is controlled by smart software with some pretty nifty features. When cornering, CATS will allow the inner wheels' dampers to return to the soft setting for better ride. At low speeds, the system switches the rear dampers to firm slightly ahead of the front pair to reduce transient understeer, with the aim of improving turn-in. At higher speeds, it does the opposite. The idea is to slightly increase transient understeer, with the aim of improving stability.
Drive the car and it's hard, if not impossible, to feel the switching activity of the CATS system. With many car makers, marketing department pressure would have dictated the inclusion of some dopey system to show system activity. It gives the salesman one more thing to point out to the prospective customer, you see. Looks like the marketing department of Jaguar was outmanoeuvred by the engineers, who undoubtedly hate having to work on such irrelevant rubbish. All you notice from the driver's seat is that the S-Type R's ride is lovely and its handling loveable.
The S-Type R's leather upholstered front seats smell more leathery than most. They're also plenty supportive, despite lacking the bulky cushion and backrest bolsters that make getting into and out of the SV300 a bit of a pain. With seat and steering column both power adjustable, any driver should be able to set up the Jaguar perfectly. The cockpit is a snug fit, but only the tall - like me - will have any problem. The redesigned instrument panel and centre console, while much more attractive than the S-Type's original, occupies space where a tall driver's left knee wants to be.
Likewise leathered, but in contrasting anthracite and mustard instead of the S-Type R's basic black, the SV300 is a looser fit; plenty of room in all directions. But the HSV's driving position isn't as good as the Jaguar's. You sit high in the Australian car, but can snuggle deep down into the English one. I've said it before, but I'll say it again: ever since Holden moved to electric seat-height adjustment with the VT five years ago, I've not been able to sit as comfortably low as I'd like to in any Commodore. But let's get back to the driving.
The SV300 is a happy cruiser. Even though it runs an even shorter final drive ratio than the 255kW LS1-engined manual transmission HSV models, which in turn have a ratio shorter again than Gen III-engined manual Commodores, the C4B-powered car doesn't have to raise its voice above a whisper when dawdling along at the freeway speed limit. The short 3.91 diff also means that the silly 0.50 sixth gear of the T56 gearbox is actually useable. The SV300 climbs gentle grades in top. Try that in another V8 Holden or HSV and see what happens...
This particular SV300 was remarkable. With more than 20,000km on its clock, it was well past the test-car pension age. The body felt tight, the engine seemed a little sweeter, and the gearbox shifted better than any other T56 I've ever driven. Still not wonderful, but not abysmal like most I've encountered.
While the drivetrain has mellowed nicely with age, the rest of the car is just as remembered: steering that's both too heavy and too sharp on centre, with a too light and rather vague period beyond, followed by acceptable assist and feel further on; cheap and cheerful strut front suspension that has too-firm springs or too-firm damping or both, making the nose bob about; semi-trailing arm and toe-control link rear suspension that is decades out of date, and sometimes feels it. But, despite such shortcomings, heaps of grip and fine balance.
Turn off the traction control - highly recommended because the system's pulsing-throttle-pedal-feedback warning feature is awful - and you'll find the SV300 delivers a wonderfully predictable transition into throttle-provoked rear-end steering. Want to give the front tyres a hard time instead? Then heave hard on the wheel when turning in and the front Bridgestones will scrabble briefly for grip.
Fact is that the SV300 feels faster than it is. It bobs and bucks, shouts and slides, making every hard-charging moment melodramatic. The S-Type R, on the other hand, doesn't make a fuss of carving corners quickly.
The Jaguar has a DSC (Dynamic Stability Control) system. It's a technical step ahead of mere traction control, introducing the ability to brake individual wheels to quell both understeer and oversteer before they can develop into full-blown ... um ... situations. It's not the least intrusive such system I've ever sampled. Certainly when it begins to nip at the front brakes, it causes a fore and aft wheel oscillation that can be felt. To discover the S-Type R's true nature, turn off the DSC.
What you'll find with the safety net removed is awesome grip and excellent balance begging to be exploited. The S-Type R's steering is light, but perfectly consistent, packed full of feel, and nice and linear. None of the SV300's dartiness just off centre, none of the weird variations in weighting. The only respect in which the HSV's steering is superior is in its greater resistance to kickback. And the Jaguar only does it under extreme pothole provocation.
I must mention, also, that the Jaguar's steering was the only source of trouble with the S-Type R. After testing was completed, without incident, it was into the studio for glamour photography. Time came to pack the lights and leave, and there was no assistance. Once the car warmed, assistance mysteriously returned. After this there was an unhappy noise from the ZF power-steer pump. We returned the car early to Jaguar. The rarity of the problem meant that the pump was removed from the car for shipment to England, where a full forensic examination will be performed. Maybe it's just coincidence, but the last power-steer problem I encountered was with a BMW M5, also fitted with a ZF pump. When working, the Jaguar's sensual steering encourages the driver to go deeper, harder, faster. Give in. I did.
The S-Type R's big brakes - Jaguar-branded, but Brembo beneath - have more initial bite than the HSV's Premium kit, with similarly spectacular stopping power. But because the English car's suspension copes better with buffeting bumps, its grip under brakes is more reliable. In the HSV, brief activation of the ABS system lets you know it's struggling a little.
With wider front tyres than the HSV wears on all four corners, and rear tyres that are larger again, the Jaguar has a clear contact-patch advantage. The grip of the broad Continentals turns into extra corner speed. Vicious turn-in technique will cause momentary understeer in the S-Type R. Vicious throttle application on exit will cause fleeting oversteer. In between there's neck-straining cornering.
The basic handling characteristics of the HSV and the Jaguar are more remarkable for the similarities than differences. But the S-Type R operates on a higher plane. More speed (except in a straight line), unflappable competence, utter confidence; a great driving experience.
In comparisons like this, price isn't important. It's not the players' pay packets that count, it's the score at the end of the match. And the S-Type R posts the most points. Performance that's far more user-friendly, even if the raw numbers aren't quite a match. Decisively superior ride. More composed handling. Better driving position. Similar braking ability, but with better bite.
Modern Jaguars don't turn me on. Mostly they're second-rate also-rans. But the S-Type R is different. This is a car that's earned my respect and admiration. Unlike any Jaguar I've ever tested before, this is one I want to drive again.
And the home-team hero? Not disgraced by any means. Especially when it has the performance to outrun a car that costs $60,000 more. But the SV300's humble Commodore origins are transparent when held up against something with the technological grace of the S-Type R.
I suspect that for HSV's loyal audience, the rough edges are part of the attraction. Success achieved despite the handicap of a lowly background is something that deeply appeals to Australians. But the Jaguar was born with advantages that just can't be ignored. And the R makes the most of the S-Type's better start in life.