Cycle News - Archive Issues - 2000's

i{Ekt Vee Two Sprintex Horley-Dovidson V-Rod rotating impellor to accel- erate air to high velocity, creating pressure as it backs up within the port. Or the Roots- type vane blower that positively dis- places a given amount of air into the discharge port, again caeating pressure in the manifold as a result of overfilling the engine with air. "The difrererrce betvreen ours and tlEirs is that the Roors iust blows air into the plenum chamber, brought it to market. So successfully, that Vance & Hines - a company not noted for second-best engineering, as well as the official H-D drag-racing team and NHRA Pro Stock Champions with their V-Rod inspired racer - are now marketing the Sprintex V-Rod kits in North America. Wi(h more ahan 70.000 V-Rods leaving Kansas City in the past four years, it seems likely there's enough potential customers around the world for this amount of bolt- on performance to iustify the $6200 invest- ment, even before Vee Two addresses the Ducati application that's coming up next. To create a 644-pound motorcycle with 142 rear-wheel horsepower (compared to 102 hp for the same engine on the same dyno before being "Sprintexed") that wheelspins off the line and will also wheel- ie in spite of its rangy l7l4mm wheelbase, no mechanical alterations are needed to the stock Harley motor. lnstead, the Sprintex kit (that entails a 30.8-pound weight penalty to a stock V- Rod) includes a dedicated compressor unit that is compact enough to fit under the stock V-Rod dummy-tank cover (the real fuel tank is beneath the seat), and is driven via a Gates poly-V belt off a pulley on the efld of a longer replacement for the shaft that is normally turning the Harley motor's water pump. This entails junking the stock pump and replacing it with an electric one - an operation that on its own releases an extra 5 hp on the Vee Two dyno. Br-rt except for the alloy tower on the right of the engine between the cylinders, there are no other give- aways to the conversion havinS been done and. what's more, you can rcinstall the original H-D parts at any time, for whereas ours compresses the air inside the blower," explains Henry "That's why you s€e 'Kompressor' on the back of Benzes - the Sprintex design is similar, and the Sreat advantage is a lower discharge temperature, which creates a denser charge and greater volumetric efficiency, which is also the reason we don't need an intercooler We use 8-psi pressure for the V-Rod, but can tlveak ( up to 20 psi. because the Sprintex unit has adjustable boost for hagh-performance applications like drag racing. Do you want another go with the boost cranked r,rp, after you've had a bit of practice at mastering the clutch? There's a bloke round here with a Porsche 996 - maybe yor-r can go find him to mumbo with, if HSV Holdens are too tame?" An additional benefit of the Sprintex desiSn is that boost can be eliminated to reduce load, improve rideability and enhance economy with a simple blow-off valve, which diverts boost when it's not required, like when cruising on a freeway. So riding round town with the engine turn- ing over lazily, the supercharged V-Rod is as relaxed an easy rider as Harley intended it to be, pullinS cleanly off idle away from city intersections with not much hint of the gargantuan grunt that's waiting to be unleashed - with iust an 0.5 kgm difference in torque between 3500 rpm and 7000 rpm. ls that flat, or what? ''The big difference i5 that tt€ stock Harley motor makes its maximum torque at almo6t 9000 rpm, so close to redline," says Sprintex CEO Tony Hamihon. ''Ours makes 80 per- cent of its peak torque at 3200 rpm, and that's dre difference. And though we've got the Vance & Hines pipe fitted for the sound of thunde[ the kit is designed to work widi a stock Harley exhaust. Wherher )oLrr V-Rod's fitted with a catalytic converter like here in 04 or without one as in the USA, it makes no eflective difference - our systern will give you the same hoEepower with or without the cat which underlines why the Sprirtex q/stem is so good in restoring the performance lost by rneeting emissions rules." So crank up the gas, and the Sprintex- blown motor completely fulfills your expectations of urge with wrist-yanking insistence and zero throttle lag. lt's a total- ly tractable real-world performance pack- age in a way that no turbo motorcycle l've ridden has ever been. That presumably comes not only from the presence of the blow-off valve, but also from the mapped- in refinement delivered by the electronics that ry the boost in accordance with such parameters as engine rpm and throt- tle openings - making the absence of a boost 8au8e on the bike rather puzzling. But, rather improbably, this is a com- pletely civilized street dragster in every sense of the term, with only the on/off action of the zero-wear carbon clutch a hindrance to rideabilit/. This is fifted to counter the hiSh-wear factor of the stan- dard V-Rod clutch when subiected to this kind of performance, but is also zero-slip. Vee Two will soon have a centrafugal- type street .lutch to combat this, which they'll sellas a V-Rod a{termarket part sep- arate to the supercharger kit, offering srn- gle-finger operation while delivering pro- Eressive bite. They'll also be able to sell that to their Ducati customers. "When it comes to new technology and innovative engineering, nobody dares to risk bein8 first - but nobody wants to be second," says Hamilton. "Sprintex is so confident of the benefits of our tech- nology, we're prepared to develop a ded- icated supercharging package for any manulacturer on a no-risk basis - they don't pay us a cent upfront, until we prove to them that it works. That's the way we've successfully developed our links in the automotive sector, and we're happy to do the same thing with bikes, where it seems manufacturers are sur- prisingly conservatrve about adopting new technology. Look how long it took for fuel injection to become common- place on bikes, even though everyone knew it had to happen eventually. We believe supercharging is equally rnevitable, especially as a means ofge[ting around ever-stricteremissions legislation. Harley are finding that out for themselves right now - so, who's next?" Okay, any akers? Gll 34 MAY 24, zeo6 . CYCLE NEWS maybe if you wanted to trade up to next year's model. "The original Harley EFI has twin throt- tle bodies sitting an an airbox complete with filte('' explained Brook. "But we remove all this and drop in the Sprintex compressor and our own plenum chamber, then fit our own 53mm throftle body with a single buterflI. We retain the stock in,ec- tors, but there's a third supplementary one that comes on at full boost. because the stock ones can't flow enough fuel to keep up. But set up like this, the engine idles as sweetly as it does when stock." That's because the third iniector is con- trolled by a secondary Vee Two ECU that is part of the kit, while the stock ECu is also retained (as on all Sprintex super- charger installations), to remain in control of closedJoop fLrnctions that the vehicle has been homologated under - as wellas to take advantage of the manufacturer's work in mapping the ECU to compensate effec- tively for variations in climate or altitude. "We're not tryinS to be 'cleverer' than Harley or Ducxi," says Brook. "iust ofrer sub- stantial extra perforrrEnce while piggybacking onto their existing engine management. Like we say - it's bolt-on performance!" The Sprintex supercharger comprises twin intermeshing helical-screw rotors, one convex and the other concave. They counter-rotate without ever touching inside an alloy housing that is machined from solid by Vee Two, and thus, displace a set amount of air from the inlet system to the discharge port wirh each rotation. The design actually compresses the charge berween the rotors and rhe housing, difer- entiating it from other q/pes of supercharger, such as the centrifugal blower, which has a ."t I "' a 'a' I t i .1; l 1 t t/ t 4 \ { I V.o Two'r Bieok H.nry, lhc broins behind tlre superthorged V.Rod,

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