Story: Ken Wootton
Photos: Arthur Thornton & KW
Could this be the world's most sorted GSX-R1000? With the same rear-wheel power as Shawn Giles' Superbike, the PTR Stealth packs one helluva ride...
"Excuse me officer, I was wondering if you could help me out? You see, I've got this bit of plastic with my face on it that says I'm allowed to ride a motorcycle.
"And we can save each other a lot of hassle and paperwork if you just take it off me right here and now and look after it for the next month - maybe even the next six if you feel like it."
Those were the thoughts running through my mind as I buttoned off the throttle and let the PTR Stealth approach the looming 60kmh speed sign at a velocity that would hopefully prolong my legal riding rights at least long enough for me to grab a cappuccino and a lemon tart at the Yea bakery.
What's that they say about the condemned man ate a hearty meal? Hopefully my last food intake won't be limited to a frothy chocolate stain under my snout and tightly pursed lips from a tangy tart...
SELF-INFLICTED PAIN
My sustenance stop gave me time to recap on the past couple of hours in the saddle of the Stealth - as well as giving my lacerated right knuckle time to regain some feeling.
Lacerated knuckle? I'd like to pretend it was from hanging on to the 'bars of the 173ps weapon as the front end pawed skywards, the rear tyre spitting gravel chips out the back as the Stealth rocketed out of the turn and towards the horizon like the F-117 bomber it's named after.
Sadly my self-inflicted injury wasn't quite that glamorous. Those 'petal' discs on the $40,000 PTR GSX-R1000 Stealth may look the business, but they sure know how to slice a polishing hand to the bone if you're not paying attention.
Still, my throbbing knuckle was a small price to pay for a gallop on what has to be one of the most exhilarating rides on two wheels. Errr, make that one wheel...
PROVEN LINEAGE
You see, the 'PTR' refers to Phil Tainton Racing, the performance house which runs Suzuki Australia's road racing effort. The very same PTR which has guided Shawn Giles to the past two Australian Superbike Championships - 2000 on the FIM-spec GSX-R750, and 2001 on the then-new GSX-R1000.
And Gilesy looks odds on to make it three in a row in 2002 with a healthy 67pt lead and only one round to run (with 76pts up for grabs) in this year's championship, at Sydney's Eastern Creek Raceway on November 8-10.
Okay, it goes without saying that PTR knows how to screw a GSX-R1000 together. So good in fact that the road-going Stealth pumps out 12ps more at the rear wheel than last year's championship-winning GSX-R1000 - and exactly the same 173.3ps as Gilesy's current racebike. Yeehaa...
The reason for the horsepower boost is that this year's Aussie SBK regs allow for the fitting of race camshafts, which when combined with a full season of development and some careful PTR remapping of the fuel-injection system have unleashed the additional ponies.
Compare that 173.3ps to the 144ps that a stock GSX-R1000 testbike pumped out in AMCN's recent Big-bore Sportsbike Shootout (Vol 52 No 2), or the 129ps that a CBR954RR FireBlade develops, and you don't have to be a Einstein to realise the figures are impressive. Damn impressive. Check those dyno graphs on page 27 if you need further convincing.
MAJOR EFFORT
Of course, just like the television ad says, power is nothing without control. And that's where the Stealth shines.
In fact, the powerplant is so well sorted that at first I was lulled into a false sense of security as to just how potent this thing is.
Up to around 5000rpm there's not much to separate the PTR Stealth from a stocker in rear-wheel power, and in fact the stocker arguably has slightly more torque. That's no doubt a trade-off with the Stealth's Yoshimura full-race cams, the very same ones that Giles' #1 Superbike uses.
But from 5K onwards the Stealth just builds and builds and builds until it becomes a major physical effort just to hold on.
This is one of the few streetbikes that could benefit from a bum pad to keep the pilot locked in place. But I guess you'd expect that with around 20 percent more mumbo to play with at 11,000rpm than on a stock GSX-R1000. And believe me, a stock GSX-R1000 is no limp biscuit. Yikes!
The slightly higher Powerbronze screen was a help here, as it kept some of the windblast off my shoulders and bonce, but there's no doubt a Giles-type riding style is encouraged - push forward on the pegs, pull forward with your arms, and keep your head and weight well forward.
With the Stealth's PTR footpegs set 30mm back compared to the stock pegs the rearset brackets help immeasurably with this 'push forward' technique, although the 25mm-higher positioning of the pegs saw my gangly pins getting a little cramped on longer road rides. Swings and roundabouts I guess.
While on the topic of Powerbronze, the Stealth also wears that company's carbon-fibre rear hugger ($240) and snazzy rear inner guard, complete with two classy taillights. It really looks the business and gives the GSX-R1000 rear-end a far more aggressive look. Money well spent at $335 I reckon.
INSTANTANEOUS EXPLOSION
Explosive is the word that best describes the Stealth's acceleration. Instantaneous horsepower. Bloody awesome.
It's the instant response that is frightening - not because it's scary frightening, but because it's just so well sorted. What ever you do at the throttle, you get at the rear wheel. I'm not sure how many hours Mr Tainton spent on his inhouse dyno to get the fuel-injection mapping sorted, but the $280 he charges for a GSX-R1000 fuel map is money well spent.
Where the Stealth varies from the Giles Superbike is that it uses a $995 Yoshimura EMS system rather than a Dynojet Power Commander, although both essentially do the same job - and that's to allow the engine's fuel-injection 'brain' to be accessed. The days of simply swapping jets and needles on carbed sportsbikes when you fit an aftermarket exhaust are seemingly long gone...
There's also an EMS accessory 'hub' (for an extra $980) that includes a powershifter, shiftlight, rev limiter adjustment and three-way switch on the handlebar to select alternative maps. Phil had disconnected the powershifter on the Stealth for the simple reason that powershifters work best when changing gear at full noise. Fine for the racetrack, but not ideal for road use, where anything less than a full-noise gearshift results in a clunky change and a massive thump in the small of your back.
Believe me, flat-shifting the Stealth at 11,000rpm on public roads is not something to be attempted by the faint-hearted - let alone anyone who wants to hold on to their licence...
Best leave that powershifter in the box for trackdays - or posing at the local latte hangout on Sunday morning.
AMAZINGLY EASY
Despite the prodigous power output of the Stealth, it's an amazingly easy bike to ride slowly. I even dropped to 2000rpm in top gear and it pulled away without a hint of transmission snatch.
There's no way I could have done that on Gilesy's 1993 Peter Jackson YZF750 Superbike (which incidentally tried to loop me staright off the back at Phillip Island's Siberia!) or the Marty Craggill Muzzy Kawasaki ZXR750R (which tried to spit me off down Phillip Island's front straight every lap). Both of those bikes had light-switch power delivery that was downright intimidating - and a powerband kick that makes an Aprilia RS250 feel like a Postie bike in comparison.
Despite loads more horsepower, the Stealth is a totally different beast. I managed to score it a couple of times on wet and miserable evenings for the ride home from Horror HQ to Chez Woose, through the challenges of Melbourne peak hour and slimey tram tracks. Interesting...
Truth be known, some of my colleagues were avoiding the Suzi key for fear of the rear hoop breaking loose unexpectedly in such conditions and dumping them and $40K worth of GSX-R on their collective sides. I had no intention of informing them what a pussy the thing could be if ridden accordingly.
Mind you, the couple of wet nights is what led to my lacerated knuckles. Not only is the Stealth full of go, but it's got a fair amount of show as well.
And that's how I got caught out by the 'petal' discs in one of my washing and polishing frenzies. Ouch.
Speaking of the discs, I was impressed by the additional bite the Braking items offered over the stock GSX-R1000 units, which feel a bit wooden with the standard pads. Sure, the stock items work okay once a bit of heat has been generated, but that's not always possible in road use.
The Braking rotors improved both feel and bite, although the Goodridge braided lines no doubt assist in that regard as well.
OHLINS MAKEOVER
The brakes aren't the only chassis improvement on the Stealth, with both ends copping an Ohlins make-over. The fully-adjustable forks look just like the top-shelf $10K full-race Ohlins items, but are in fact lower-spec 43mm road/track versions (at $3700). Nevertheless, they're something Giles can't use on his Superbike as the Aussie rules require stock forks. Score one for the Stealth.
The Ohlins unit at the rear is the same twin-speed (high and low-speed damping) unit that adorns Gilesy's Superbike. At $1769 it's not cheap, but it's certainly the duck's guts.
Tainton has revalved the shock to exactly the same spec as Giles uses on his #1 racebike, although the Stealth uses a 8.0kg spring opposed to the 7.5kg item on the Superbike. What, a heavier spring on the roadbike?
"Shawn prefers a slightly softer spring and a bit more preload," explains Tainton. "It's just a metter of personal preference."
Either way, the Stealth is firmly suspended, and that means the ride can be quite 'harsh' at slower (ie legal!) speeds.
It needs to be firm though, as with that much instant power you don't want the rear-end squatting every time the throttle is twisted.
The Stealth is one of those bikes that gets better and better the faster you ride it. It's probably an ideal Isle of Man bike, but I don't think I can match David Jefferies laptimes on his GSX-R1000 to find out.
Mind you, Gilesy doesn't think the Stealth is too firm - probably because it's got a normal seat rather than the little pad he's used to on the #1 bike. After his 'running-in' session on the Stealth at Sydney's Eastern Creek Raceway he was full of praise.
"It's fantastic - it's got as much power as my racebike bit it's more comfortable."
SIMILAR SPECS
The Stealth cops similar chassis specs to the Giles bike as well, although not quite as radical. The rear ride height has been raised fractionally, which quickens the steering a tad, but there was no instability trade-off that I could find.
Then again, I wasn't lapping the Isle of Man at an average of over 120mph, so it's a bit hard to tell. Either way, the Ohlins steering damper could well have not been there so true did the Stealth track on the road.
And that just about sums up the PTR Stealth. All the performance mods on the bike have been tested and proven in the hotbed of competition, with a dyno graph that offers proof of its lineage from the #1 Superbike of Gilesy.
It's a far closer 'replica' to the real thing than any road-going HSV Commodore could hope to be. HSV GTS versus Mobil HRT Commodore, or Stealth versus Team Suzuki GSX-R1000 Superbike? No contest as to which is the real replica.
In fact, take off some of the add-on parts illegal under current Aussie Superbike rules (Ohlins forks, brake rotors, etc), fit some slicks, and I've no doubt Gilesy could go out and win a race on the thing - lights, mirriors and rego plate included!
KNUCKLING DOWN
Okay, I'm not going to pretend that $40K is a bargain for a hotted GSX-R1000. But have a look through the shopping list on page 22, and put a line through some of the cosmetic enhancements that you'd be willing to sacrifice in the name of budgetary constraint.
Now add those items up, then use the savings to attend numerous performance riding schools. Now you've got no excuse. Jump on that PTR-modded GSX-R1000 and go and win yourself an Australian Superbike Championship.
Of course, if you're like me you'll leave the Stealth just as it is and continue to blame your lacerated knuckles for holding back your racing career.
Source:http://www.bikepoint.com.au
