Supercharger, whistles, chirps and sonic booms ft Kawasaki Ninja H2

Supercharger, whistles, chirps and sonic booms ft Kawasaki Ninja H2

Most people need alarm clocks to wake up from their slumber. When your battery dies, you need to jump-start your vehicle. When you need to quicken the pace, you need to downshift. What all that implies is that sometimes you need to ‘shock’ the ‘system’. The Motorcycle industry was the ‘system’ and the Supercharger, aka the Kawasaki Ninja H2, was the ‘shock’. 

Innovation doesn’t come easy but it has to come often or else, boredom strikes swiftly. But what does one do in the name of innovation to leave a mark… forever! Do something that even the passage of time itself cannot kill or make something that is revered for ages. But what? 

Supercharge a motorcycle, give it more than 300 bhp, make it touch 400 km/h and make it reliable too. Sounds too good to be true but… then again, the Japs have always been good at that kind of stuff. Take a bow, Kawasaki, for making a motorcycle saying the name of which is incomplete without profanities. And that’s a compliment. Perhaps one of the biggest we can give. 

The ‘Avatar’ in a world of benders

The Kawasaki Ninja H2 came out in 2014 when the industry… Let’s just say that it was not the most enjoyable period. Kawasaki, perhaps, grew tired of the good ol mills and new graphics. The legendary Ninja moniker needed a game-changer. But how? 

Turbochargers and superchargers had been around for a while. But motorcycles with those… There were a few experiments but nothing concrete. So while Nick Fury went ‘Ant, Boot.’, Kawasaki went ‘System, shock.’ And while most of us have lapped up the spec-sheets and those who have ridden it are all praises (including us), the execution of such a thing COULD NOT have been easy. So let’s talk about it. 

An engine needs fuel and air to produce power. More fuel equals more power, yes, but it needs oxygen to burn just like everything else (including us). Anyway, one way to go about it is the age-old adage no replacement for displacement. But the problem is the added weight… even more so in case of motorcycles. 

When you eliminate the impossible, whatever remains, however improbable, must be the truth. So, someone went push more air… push more air and so, superchargers and turbochargers or forced induction happened. This method gained popularity in aircrafts which suffered from power loss at high altitudes due to the less dense air. But on the ground, some adventurous folks were like I turbocharge, I go fast, I have big cojones. And that’s how it started. 

Without diving too deep into the differences between turbocharging and supercharging, we’ll simply talk about the fundamental difference. Forced induction devices are, in simple terms, air compressors. In turbocharging, the impeller (the ‘air maker’) is driven by the exhaust gases and is superchargers, it is attached to the crankshaft for the spinnies

Turbochargers suffer from turbo lag which happens because of the time it takes for the exhaust gases to spool the turbocharger for optimal boost. That can be taken care of by Twin-Turbo’ing or Bi-Turbo’ing which simply means two turbos and too bulky for a motorcycle. And even if someone tried it, the added bulk of a necessary intercooler (to cool the compressed air (which, if not done, could cause detonation or knock) was a massive dissuading factor. 

The folks at Kawasaki went ‘Hmm, what do we do?’ and suddenly someone googled ‘River Mark’ and they were like ‘Aha, let’s ask Kawasaki Heavy Industries if they have something’. And of course, they did. An industry that has spent years ruling the land, sea, and most importantly, air… of course, they did. 

Kawasaki’s Gas Turbine and Machinery division (they manufacture jet engines) came up with the proverbial Chemical X, a small and efficient centrifugal supercharger. And that, friends, is the crown jewel of the Ninja H2. 

We rode the Kawasaki Ninja H2 for 20,000+ km during the PowerTrip360. 

That is how the 998cc inline-4 engine makes that astronomical amount of power in the H2R and that’s what makes the street-legal H2 so exciting. The sheer amount of raw power and torque, ready to scram you through the space-time continuum, ready to scare The Flash into submission… That is perhaps the exact feeling that was amiss for so long before the H2 came out! 

But what is so exciting about it? It’s just supercharging. Yes, but to truly understand the genius of this motorcycle, we must talk, briefly, about superchargers. There’s the Twin-Screw supercharger, there’s the Roots supercharger and then there’s the centrifugal supercharger. 

In order to keep it brief, the only thing we need to know is that the centrifugal supercharger is the most thermally efficient way of forced induction (therefore no intercoolers) but they also lack the low-end grunt. They need to be spinning fast to provide a significant boost. They’re peaky and that’s not good for an already peaky inline-4. So, what next? Magic… or science that we don’t understand yet. 

Enabled by potential, limited by… err… limiter

Next is the magnum opus of what this whole article is all about; the planetary gear drive with a two-step system. A simple explanation is that using the right kind of gear, you can have the impeller of the supercharger spinning fast enough to generate enough boost even at lower engine RPMs. The caveat is the excessive boost at higher engine RPMs.

Enter the two-step system. So, at lower engine RPMs, the first drive is activated which translates to a faster spinning impeller and thus, more boost while at higher RPMs, the second drive is activated which makes sure that the boost is not excessive by reducing the speed of the impeller by using a different gear (one with a lower ratio). 

The bottom line is that the planetary drive makes sure that the Ninja H2’s supercharger is never short of boost to provide and the two-step system ensures that there is never too much, perfectly balanced, as all things should be. And trust us, those who are thinking that there is no such thing as excessive- a 2.7” impeller that can spin at up to 1,30,000 rpm… it’s breathtaking, and not in a good way if left unchecked. 

At an engine RPM of 14,000, the impeller is spinning 9.5 times faster. That is the beauty of the planetary drive system. And yes, that’s with the second step of the drive which makes the impeller spin slower relative to the engine RPM. The first one which is active at lower RPMs has an even higher ratio. 

The significance of the famous River Mark

So, supercharger, good tech, more boost, more power, more torque, more responsiveness and a heck of a lot of fun. But motorcycle engines spin up quickly and run really high compression ratios so it is not exactly as easy as bolting a supercharger on an engine and we are good to go. 

In addition to the reduction of the compression ratio inside the cylinders, a lot of exotic (and very tough) materials are at play in the H2’s engine. It is a delightful symphony of the choicest of technology, heavily seasoned with the best of the components, garnished with Japanese precision, and served with a positively sublime sound to accelerate your pulse and induce an adrenaline rush that would make Pavlov proud… And that’s just the engine! 

Coming to perhaps the most important thing- even more important than the sheer satisfaction that the performance of the H2 provides or the fact that it is an unrivalled masterpiece of engineering- the soundtrack. This Ninja doesn’t need to deploy stealth tactics, it is a master of the Dark Arts and its whirring melody is the ‘Imperio’. While inline-4s sound awesome, the Ninja H2 sounds even better with the chirps and whistles. And those are two different things. Let us explain.

A BatMobile against the might Ninja H2? Bring it on!

So, when you rev the engine, boost is produced and you go cray cray fast. But that happens to the boost when you let up the throttle or when you upshift or downshift? Chirp happens. The airbox features a relief valve which lets unnecessary (at that particular moment) boost out and hence, the chirp. The same thing happens in case of turbochargers if you’re familiar with the term ‘blow-off valves’. 

Here, take a listen: 

VOLUME UP! the best part of the #ninjah2 is not the power ( 280 bhp ), it’s the sweet insane flutter of the #supercharger ! ————-#xBhp #kawasaki #akrapovic #bikersoul #bikerlifestyle #bikersofinstagram #superbikesinindia #superbikes #motorheads #motogram #motorcycles #instamoto #instamotogallery #motographer #australianmotorcycle #australia #puttyroad #agvhelmets #daineseCrew #sonyactioncam Akrapovic Exhaust System #xbhp

Posted by MotoGrapher on Friday, 15 March 2019


Now, the whistle is an entirely different thing. As we mentioned earlier, the impeller can spin up to 1,30,000 RPMs sucking and compressing an insane amount of air. At high engine RPMs, and hence, impeller RPMs, that is what you hear as a high pitched whistle along with the already sweet note of an inline-4 ripping away. It even lets off tiny sonic booms… and we are still talking about a motorcycle here. 

There have been a lot of Ninjas (and others) from Kawasaki that have had a humongous impact on the motorcycle world. And while the mirror-finish paint may have taken away a lot of the ‘green’ from the Ninja, it is still a Hulk… in every sense of the word. 

It may not be serums and gamma radiation, but what the Hulk does to a city when he goes bananas, it is the same thing that the H2 is capable of doing to the psyche of the unfortunate folk who encounters one on the road and says, “You’re big, fought bigger…” Or maybe you don’t let them say even that and just speed away and let the chirps, whistles, and sonic booms drown out the hissing sounds of the freshly inflicted burns.

While the above may be enough to deem the Ninja H2 as a game-changing motorcycle, there’s a lot more. The overall design, the attention to detail, the aerodynamics at play, and the choice of components to keep this monster on a leash. So, at the end of the day, the River Mark logo that the H2 dons on its face… it has earned it. 



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