Recently leaked patent filings hint at the famed ADV getting a supercharger
When Kawasaki had originally launched the H2 duo, the world watched in awe, and tomes upon tomes were written on the collaboration between Kawasaki’s Heavy Industries and motorcycle manufacturing facilities to develop, tune and ultimately manufacture the H2 and H2R. Subsequently, Kawasaki launched the H2 SX, covering the sports tourer segment, and finally the Z H2, effectively putting its stamp on the naked segment as well. That left only two broad segments, cruisers and ADVs. Guess what happened next?
Ah, we’re too bad at keeping secrets; so without further ado, let’s get to the matter at hand. Honda, in its infinite wisdom (both as a brand and in their proficiency in making off-road bikes and ADVs) has been developing a supercharged version of the CRF1100L Africa Twin at their R&D facility in Japan.
So what’s new?
As shown in the patent designs, Honda has placed the supercharger just above the transmission, similar to what Kawasaki has done with its H2 series of bikes. However, that is where the similarities end. This is because Kawasaki had adopted a purpose-built centrifugal supercharger which, in action, is similar to how the compressor of a turbocharger works, albeit being driven by engine revs, to push greater volumes of air into the engine. Consequently, they work best only when the engine itself is operating at full power.
Keeping this in mind, perhaps, Honda has used a twin-screw design. This involves two longitudinal rotors which not only sucks in air, but also compresses it before introducing this denser air mix into the engine. The benefit, therefore, is better thermal efficiency (the ratio between heat produced and amount of energy generated), with significant boost from lower RPMs. Additionally, a twin-screw supercharger does not use engine oil.
That said, a twin-screw arrangement is not without its disadvantages. Chief among them is a significant loss of power at lower RPMs (called parasitic loss) incurred as energy from the engine is applied to enhance the supercharger’s ability to function effectively and produce power. Next, while a centrifugal supercharger works best at the top-end (and not necessarily as well throughout the rev-range), a twin-screw supercharger, courtesy a wider spread of power, means there’s no real top-end ‘kick.’
Lastly, and most importantly, a twin-screw supercharger is not only costlier to manufacture, but also requires an intercooler, which will no doubt add significant weight to what is already a heavy (252kg) ADV. Hence, it’s safe to say Honda will have its hands full with the pricing and construction (and packaging) of this supercharged Africa Twin.
Now, let’s briefly move away from the supercharger’s chatter (see what we did there) and back onto, well, the engine itself. The (most probably) 1084cc single overhead cam (Unicam, in Honda parlance) parallel-twin, currently making 101bhp and 105Nm, will use both direct as well as indirect or port fuel injection, i.e. both within the combustion chamber as well as the intake port, which will no doubt make the Africa Twin more efficient, boosting power as well as complying with emissions regulations.
The final question...
...is of when will this supercharged Africa Twin go into production. And on that, your guess is as good as ours. No, we’re not being sardonic. You see, way back in 2017, leaked patent drawings from Honda showcased a supercharged V-twin engine in what looked like a naked streetfighter body, leading to wild guesses about a supercharged iteration to the CB1000, or even a naked variant of the VFR1200.
That said, the market for ADVs has progressed far beyond the Africa Twin. In fact, despite having a larger engine, it makes less power than the Kawasaki Versys 1000 (1043cc, 119bhp, 102Nm) and even the recently launched KTM 890 Adventure R (889cc, 105bhp, 100Nm). Further, it is not even in the vicinity of the established players like the BMW R1250GS (1254cc, 134bhp, 143Nm) or Ducati Multistrada 1260 (1262cc, 158bhp, 129Nm). And considering Ducati, this gap will only widen once the Multistrada V4 comes in to play, as this one is aimed directly at the mad, mad KTM 1290 Adventure, which makes 174bhp and 144Nm from its 1301cc V-twin engine. At this juncture, a supercharged ADV from Honda would really turn the tables.
So who wouldn’t want to see Honda wiping the smiles off the smug Europeans' faces? We know we would!