Honda Developing Supercharged Africa Twin

[Hugh Janus]

Scotty, I need more power. Honda’s looking to supercharge the Africa Twin to get it. (Jeff Allen/)

We’ve got our hands on proof that Honda’s engineers are working on a forced-induction version of the CRF1100L Africa Twin with an updated, direct-injected engine boosted via a twin-screw supercharger.

The evidence comes in the form of several newly published patent documents that have emerged via the Japanese patent office. They show detailed designs for the supercharger system, which has been designed to fit around what appears to be a largely unchanged Africa Twin chassis. Allied to a direct-injected version of the parallel-twin, 1,084cc Unicam engine used in the existing CRF1100L, the result should be an adventure bike with far more than the 101 hp the current Africa Twin can muster, along with a big hike in torque.

RELATED: Is Honda Developing An Africa Twin Street Model?

New design drawings suggest Honda’s new supercharger will fit into the existing Africa Twin’s chassis. (Japanese Patent Office/)

While the Africa Twin is among the most convincing adventure bikes on the market thanks to its light weight and serious off-road ability, there’s no doubt it’s short on power, at least on paper, when compared to its rivals. BMW’s R 1250 GS makes a third more horses than the Honda, with 134 hp, while Ducati’s Multistrada 1260 manages a claimed 158 hp. In 2021, the upcoming Multistrada V4 will raise the bar even further with something north of 170 hp on tap despite using an engine that’s not much larger than the Africa Twin’s.

Honda’s supercharger looks like a twin-screw type, which should be better suited to low-rev applications. (Japanese Patent Office/)

Kawasaki’s H2 range has already conclusively proved that engine-driven superchargers have a future on two wheels. With none of the unpredictable throttle response or lag of an exhaust-driven turbocharger, superchargers instead offer a gradual increase in boost as revs rise, offering a feeling more akin to a larger-capacity, normally aspirated engine than a small, boosted unit.

Honda’s design might be supercharged, but it’s quite different than the Kawasaki H2′s arrangement. For starters, Honda has opted to use a twin-screw supercharger instead of the centrifugal supercharger that Kawasaki employs. That means the Honda design is a “positive displacement” supercharger, which is good for a wider spread of torque from very low revs, while the Kawasaki’s centrifugal supercharger—which works like the compressor section of a turbocharger—is more suited to high-end power and needs more revs before it’s able to provide a significant amount of boost.

RELATED: 2020 Honda Africa Twin DCT First Ride

Patents show the supercharger mounted above the Africa Twin’s gearbox, with dual injectors getting fuel via a camshaft-driven pump. (Japanese Patent Office/)

Honda’s design drawings show the supercharger mounted above the Africa Twin’s gearbox, in roughly the same place that Kawasaki puts its centrifugal blower, with the intake air routed from the air cleaner into the left-hand side of the blower.

In the supercharger the air is compressed and pushed into an intake duct, before going through two conventional throttle bodies and into the engine. There are two sets of fuel injectors, with one pair mounted in the intakes just ahead of the throttle plates and a second pair squirting fuel directly into the combustion chambers.

It’s not the first time we’ve seen evidence that Honda is working on a direct-injected Africa Twin—the first patents for such an engine emerged more than a year ago—but we haven’t seen a dual-injected, supercharged version before. The latest set of patents expands on the direct-injection idea, explaining how a camshaft-driven high-pressure pump provides the fuel supply to injectors sitting between the inlet valves in each cylinder. These fire relatively late, after the exhaust valves have closed, at an angle that means the fuel is caught in the airflow entering the cylinders through the intake valves in a way that reduces the amount of fuel sticking to the cylinder walls.

RELATED: Honda Developing Direct-Injected Africa Twin

Intake air comes from the air cleaner to the left side of the blower. (Japanese Patent Office/)

Honda’s design incorporates a bypass system to allow air to move between the air cleaner housing and intake passage at low revs or small throttle openings. A computer-controlled butterfly valve opens and closes the bypass as necessary and a pressure-relief valve is also fitted in the intake duct to release any excess boost—say, when the throttle is snapped shut at high revs, directing the overflow back into the air cleaner housing.

Injectors between the inlet valves of each cylinder fire after exhaust valves have closed. (Japanese Patent Office/)

Although a patent filing alone doesn’t mean that a bike is definitely going into production, it clearly shows what a company is spending its R&D budget on. And with multiple patents filed around the supercharged, direct-injected Africa Twin—and extremely well-resolved designs on display—there’s every indication that this is a live project at Honda. There are probably prototype supercharged Africa Twins already under test somewhere in Honda’s development department. Will they reach showrooms? We’ll have to wait and see, but since the market’s appetite for powerful adventure bikes is showing no sign of waning, and Honda doesn’t currently have a player in that part of the field, don’t bet against seeing more of this project in years to come.

Source