The Aprilia's top-end performance is totally addictive, building strong and hard from the 11,000 rpm switchover point on the variable-intake system, all the way to the 15,000 rpm limiter, at which point the electronic program on the ride-by-wire throttle simply stops the engine revving any higher. There's no staccato cutout, no jerky hiccup-just no more rpm. Bottom-gear pickup from a closed throttle is explosive, so this is best left for use only when leaving pit lane or the starting grid, when the Aprilia Racing ECU's launch control can do its stuff. Otherwise, always use second gear even out of slow hairpins, even with the tall Mugello gearing. The Aprilia will pull hard from as low as 7000 rpm; it's much torquier than the even more oversquare BMW S1000RR.
This twin-cylinder type flexibility enabled Biaggi to gear the V4 to use just five gears at Brno, where the Aprilia was comfortably fastest through the speed traps at 282.70mph-in fifth gear! The Aprilia jumps out of turns like no other current superbike, and especially not a twin-cylinder one-as Nori Haga found at Magny-Cours, where the works Ducati rider spent many laps parked behind Biaggi's RSV4, unable to match the Aprilia's acceleration out of the French track's many second-gear turns. By the time he eventually muscled his way past, it was too late to catch Ben Spies for the race win.
World Superbikes are rapidly...
World Superbikes are rapidly approaching MotoGP machines in electronic trickery. The two buttons on the left clip-on manipulate the six levels of traction control, while the two buttons on the right are for launch control and pit lane speed limiter.
Aprilia's own in-house-designed...
Aprilia's own in-house-designed APX2 ECU mounted up front controls all aspects of engine and fueling control, as well as datalogging features; all can be mapped out to the specific turn on each track via the system's GPS capability.
Rear swingarm is obviously...
Rear swingarm is obviously a hand-built works part; note the rear wheel sensors built into its structure. Note the fuel pump peeking out from the fuel tank extension underneath the seat. Akrapovic Evo titanium exhaust handles spent gases.
This is one of the most distinctive-sounding Superbikes made. Yet the V4 Aprilia has the best of both worlds and very little of the worst, because it has a high-revving multi's total horsepower numbers, coupled with the flat torque curve of a twin. Working with the light, precise steering of the twin-spar frame derived from Aprilia's World title-winning bikes, this allows you to use lots of turn speed on the RSV4 in second and third gear corners at Mugello, once you've convinced yourself to use a gear higher than normal, and utilize the torque curve of that remarkable engine while revelling in the clean throttle response that contrasts so greatly with the brusque pickup in bottom gear.
So too is the major thrust of acceleration the RSV4 delivers out of a corner once you dial the power back on, with Aprilia's own in-house traction control developed on Marco Simoncelli's 2008 World champion Gilera RSA250 imperceptibly fluttering the V4's distinctive droning engine note. It may have taken the best part of the season to get it perfectly dialled in, but the Aprilia Racing ECU's traction control program is stellar, delivering more confidence as the laps go by, and you start to instinctively understand the feedback that you're getting from it-to the point that you can then start experimenting with the TC settings via the two buttons on the pad mounted on the left clip-on, with six different levels of intervention. The system can be fine-tuned by modifying the parameters corner-by-corner via the GPS system incorporated in it.