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Suzuki GSX1300R stage 2
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March 2005 |
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Is 220 horses enough?
Suzuki GSX1300R Hayabusa hot-up stage 2
(March 2005)
by Guy Allen
For those of you who just came in on this story, we're on episode three. It started some months ago when we forked over a cheque to Suzuki and were handed a 2004 model Hayabusa in return - which we named Hannibal.
The first report was on the bike in stock trim, which claims around 175 horses at the crank, circa 217 kilo dry weight, six piston brakes up front, plus suspension that has a pretty decent range of adjustment. Though no longer at the cutting edge of performance bikes, it is still a very formidable weapon, speed limited to 296 km/h and with a solid power delivery literally everywhere in the rev range.
It's arguably the pick of the performance sports tourers and has become something of a cult bike. Some will bewail the fitting of a speed limiter (which can be circumvented with a timing retard eliminator from JB Racing in the UK), but there is compensation. The GSX1300R has switched from a 16-bit to 32-bit engine management system in recent times, and seems to have scored a neat little lift in performance along the way. Bog stock, it was pumping out 164.5 horses at the back tyre. Tuner Phil Tainton reckons you add about 15 horses to get the number at the crank, which suggests Hannibal was actually producing more power than the maker's claim!
Being congenitally unable to leave things alone, I started down the long and slippery slope of hotting it up. Stage 1 involved an Over Racing titanium four-into-one exhaust system, a race pattern BMC air filter, plus a Dynojet Power Commander (which enables you to fine-tune the fuel mapping) and the services of Phil Tainton Racing in Melbourne to set it all up.
We scored 177.6 horses at the back tyre (over 190 at the crank), along with a power and torque curve that was bigger, fatter, and stronger absolutely everywhere. All this on a muffler which was surprisingly quiet and very unlikely to attract the attention of plod or the EPA. It was now becoming a bit of a monster to ride, with the low-rev oomph out of slow turns becoming almost too much and requiring a delicate throttle hand to keep under control.
We had spent quite a bit of money by that stage and you could no doubt get decent results with less expensive componentry. A set of slip-on cans on their own would make a difference - it's just we decided to go the whole hog and see how much you could do with it.
So far so good, but why not get it over the 'magic' 200-horse mark?
Tainton has done his own 200-plus Hayabusa and knew exactly how to approach it. The existing mods were left in place, but now the engine had to come out for some really serious work.
From top to bottom, the list goes like this:
Modify airbox, removing flapper valve and installing two new induction trumpets from a GSX-R;
Regrind cams for more lift and duration, fit adjustable timing cogs;
Port and polish head for optimal gas flow;
Replace pistons with 12.3:1 items (11:1 standard);
Alter barrel skirts to change windage;
Dynotune.
It doesn't sound like a lot when you say it quickly, but there is a huge number of hours involved, not to mention considerable expertise. Tainton, who prepares Suzuki's superbikes and has several championships under his belt, is a perfectionist and unwilling to let something loose until he's confident it's right.
So where did we end up? 208.9 horses at the back tyre, or in excess of 220 at the crank. We are now talking very serious horsepower, in a machine that doesn't look much different to stock and is running a quiet muffler. A bit of a sleeper, if you like.
On paper, there are some performance penalties. The power curve went from being this enormous relentless climb from nothing to something that's a little down on stock around 2500-3000rpm, overtakes the standard machine a little above 4000rpm and becomes downright feral above 8000rpm.
The effect from the saddle at the bottom end is a little less dramatic. Yes it feels down, but still perfectly okay. It's very lively at 4000-8000. By the latter figure, it's making as much horsepower as a stock machine at full noise. The last few thousand revs take a while to get your head around. In third, for example, the thing whips from 180 to 220-ish in what feels like the blink of an eye, leaving you scrambling to get the next cog in time. Truly stunning.
So what does this mean for speed? Finding enough room is a challenge. But Tainton said his similar machine would run out of revs, so he had to make a special front sprocket for a top speed run. With racer Shaun Giles in the saddle, at a radar-measured run at Avalon airport, it scored 330km/h.
While Tainton had the machine we got him to do two worthy chassis improvements. The first was to fit Goodridge braided steel brake lines, which have done a lot to improve the feel of the front stoppers.
The second was Tainton's own invention, which are shorter connecting rods for the rear suspension, which has the effect of lifting the rear substantially and effectively making the steering quicker. You also end up with more weight on the wrists, but it changes the feel of the machine from a sport tourer to something more sport oriented.
Hannnibal's character has changed significantly. In combination with the now super-lively engine and shaper brakes, the quicker steering makes the whole thing feel like a bigger and more powerful GSX-R1000 (now there's a scary thought!), albeit with more comfortable suspension rates.
It may not be for everyone, but with a fresh set of Pirelli Diablo tyres on boards, Hannibal has become a truly exhilarating machine, though I'll confess right now it's going to take a while to come to terms with what's on tap. Oh, and access to a racetrack if it's ever to be truly cut loose...
What does it cost?
These figures are a rough guide.
Stage 1 - 190hp at the crank
Over Racing titanium 4-into-1 approx $3000;
BMC race filter $175;
Power Commander $570;
Allow 2-4 hours of workshop time for stage 1 at $66/hr, plus dyno charge.
Stage 2 - 220hp at the crank:
Engine work approx $4500;
Suspension rods $140 plus fitting;
Goodridge braided brake lines $220 plus fitting.
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