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Tech Overview

Nitrous Oxide systems is the third alternative way of forced induction. In simple terms Oxygen combined with nitrogen (to help dampen it) is injected into the inlet manifold at high pressure to give additional air the engine otherwise would not swallow. This additional air has to be accurately metered with additional fuel at the right air fuel mixture so to create the burn & in turn create the extra power.

Nitrous Oxide in small power increases of say 20 to 80hp on suitable capacity engines can be very reliable & great fun. Nitrous Oxide in large power increases 80hp to 200+hp on small motorcycle engines can be very violent & very hurtful on the engine when things go wrong. It becomes a far more specialized operation when injecting large amount of forced fed gas into small motorcycle engines. The costs of which over a protracted period can exceed that of other forms of forced induction. Nitrous systems to buy into as a performance enhancing beginner is the cheapest route non the less.

There are two principal types of nitrous oxide system that people refer to, they are…

Both of these options have their pros & cons that we are happy to discuss over the phone. On modern fuel injected engines the preference for road & racing applications has been to use dry systems. They offer better fuel accuracy & better safety from ignitable fuel vapour splash back in the air boxes of modern machines.

The air fuel ratio setting of nitrous oxide systems is determined by many factors & you need to get them right or engine failure can result. Things that can affect the air fuel ratio are as follows…..

To enable the adjust-ability of all the above can involve nitrous bottle heaters, fuel pressure regulators & engine managements etc etc. Also progressive nitrous controllers play their part in allowing wheel traction & engine safety from hard power hits.

tech overview

supercharging motorcycles

Similar to Turbocharging but instead of using exhaust gas pressure to drive impellers that then force feeds the engine induction; it uses the rotating speed of the crankshaft to drive a supercharger via belt / gears.

As the rpm of the engine increases so does the supercharger impeller increases in speed & thus boost increases. The amount of boost created therefore is directly relevant to the engine speed. Due to the size issue certain types of supercharger are not suitable for motorcycle application.

These tend to be the traditional Roots, Screw & whipple type. For compactness motorcycles have found the use of turbo style impellers driven by a gearbox a more compact design that fits easier onto a smaller bike engine.

There are several brands of aftermarket Supercharger available for use on motorcycles for example Procharger, Rotrex & Vortex to name but a few. Kawasaki have even introduced a range of factory supercharged motorcycles using a gear driven impeller. Their performance is very curtailed in stock form though offering room for good performance gains.

to debunk one myth

From our testing none of these styles of supercharger will create more low down power than an equivalent turbo. The reason is simple. There is the relevant losses of driving the supercharger to take into account but also the impeller needs to reach a certain speed from which it can give positive pressure.

A good Supercharged engine feels & acts like a much larger capacity aspirated engine. The throttle response is instant & more predictable & linear than a turbo. This is because the Supercharger is creating boost by the revs of the engine & not by the load of the throttle. This means it is creating boost on slow acceleration & fast acceleration & on a constant cruise & even on a deceleration if the rpm is high enough. This also makes the dump valve more aggressive during closed throttle in getting rid of the excess pressure. In turn though due to the superchargers nature it builds up a lot more heat than an equivalent turbo & will consume a lot more fuel than a turbo as the enrichened boosted area in the fuel map is much larger. So the instant throttle response comes at a price. More maintenance is typically needed in the belts & pulleys & associated bearings. A loose or slipping belt would loose boost & in turn power & make the map go rich.

Also be aware a supercharger will not create the same HP or Torque of a Turbo at the same boost pressure on an engine. Still the instant throttle response & with it boost on demand is addictive & makes for a great road bike or specific race application.

Big CC Racing do not recommend the use of superchargers on 1000cc motorcycle engines & below due to the poor return in power levels & performance against cost comparisons.

Big CC Racing have chosen the use of Procharger Superchargers over other brands for several reasons Firstly their direct drive gearbox has no slippage unlike the Rotrex which uses traction oil that can overheat. In turn it has no need for an oil cooling system with oil header tank etc making install on a motorcycle much easier.

The biggest factor in choosing Procharger is the horsepower return per psi of boost is just so much higher. At 10 psi pressure a Procharger with its advanced design billet wheel impellers creates 20 to 25 hp more than any equivalent Rotrex we have tested on our dyno.

chargecooling & supercharging

Is available with Supercharged applications & will deliver a power increase through the reduction of heat into the engine. Be aware that typically using the same pulleys you will experience a reduction in boost pressure. This is because the inlet air temp has fallen & in turn the pressure as the cooler air is not so expanded. 10 psi boost with a good chargecooler would typically become 7-8psi boost. This in turn helps reduce dynamic compression. A turbo by comparison would still make the same boost but more power still as the boost is controlled by the wastegate & it would self correct the air flow.

Typically a chargecooler works by using water to cool the boost down in a radiator style matrix. The boost travels through the fins & the water travels through the water tubes cooling the fins down . That water would then need a radiator or ice tank to dissipate the heat into & a water pump & hoses etc to complete the package.

variable boost control

Is also available on Supercharged applications which Big CC have been able to do on custom installations for race customers. Something our competitors are yet to catch up on. We also have experience for race customers in spraying nitrous with supercharged applications. Be aware again max boost is determined not by the controller but by the rpm & the pulley ratios. The boost controller would unlike a turbo act in a manner to reduce the boost & bleed it off. We offer 2 stage & multistage boost options.

what power level can i get?

The power potentials of your Supercharger package depends on many factors.

A simple example: A Supercharger system non intercooled could run 10psi boost = 250hp max on pump fuel with the same pulleys & a chargecooler fitted it could drop to 8psi boost yet make 270hp. Compression & tuning of ignition & fuel A/F will equally give variances.

So when asking what power your bike will make it depends upon the package that you can afford to go with in so far as engine compression & strength, turbo size & turbo system choice intercooled or not & the safety of the tuning work. Big CC Racing are happy to go in depth with you to help select your best package available for your budget.

ok what is involved price wise?

There are 4 main cost factors to supercharging a bike. They are as follows….

tech overview

Let us try to answer some of the typically broad questions that people have in deciding to  turbocharge their motorcycle engine. Hope it helps or call us: 0118 977 6755

how does turbocharging work?

Turbocharging a motorcycle is the process of using exhaust pressure to drive an impeller that in turn on the same shaft drives another impeller that pushes air into the engine & creates a forced pressurisation of the inlet air for which a reciprocal fuel ratio has to be achieved . The sizing & choice of those impellers & their reciprocal housings & other turbo features such as boost control determine many aspects of power potential & power delivery which can be tailored to a specific application.

Certain standard motorcycle engines can add 50-100% power increases. Certain modified motorcycle engines can increase their power with racing fuels by over 500%! Big CC Racing are world leaders in motorcycle turbocharged horsepower.

When you upgrade a bike with a turbo the entire fuel system will need redesigning to feed the increased air flow. Most engines will need to be strengthened not just to get to the correct compression ratio but to add strength in parts.

Some electronics may need to be added to give both fuelling ignition & power control. Some electronics may require a complete change of ECU according to racing applications . Most street systems do not need anything too complicated.

why choose turbocharging V supercharging?

Turbocharging uses exhaust gas compared to Superchargers that suffer reciprocal losses driving the supercharger off the crankshaft so turbo’s have no real loss in energy by comparison.

Turbocharging is load or throttle reactive. Supercharging is crank speed reactive in boost. This means the rpm determines the boost not the throttle position thus in turn a supercharger generates much more heat. A turbo by comparison can be ridden successfully without creating any boost if desired by simply using low throttle openings.

Typically a turbo bike will create in positive pressure per psi of boost between 8 & 14hp where as a supercharger will struggle to create 5-8 hp per psi of boost without other enhancements.

Superchargers due to creating boost by rpm will need to be enriched much more with fuel reducing fuel economy .

Because a supercharger creates boost by rpm & not load it will be positive in boost not just on acceleration slow or fast but at a constant cruise or even on deceleration. The turbo only creates boost when you load the engine with more throttle. Less heat & more economy.

Turbocharging offers easier & variable boost control via its wastegate. You can choose the power to ride at according to road or race conditions etc.

what power level can i get?

The power potentials of your turbo package depends on many factors. Here are a few below

A simple example: A Stage 2 street turbo system non intercooled could run 12psi boost = 320hp max on pump fuel providing the engine compression ratio has been dropped sufficiently . On a fully built motor using high octane fuel it may run up to 450+hp but it would need a fully strengthened engine for this. If people choose to risk turbocharging a stock engine then the dynamic compression under boost is the restriction. A Hayabusa with stock compression at 11:1 cannot use more than 7psi boost safely on pump fuel.

So when asking what power your bike will make it depends upon the package that you can afford to go with in so far as engine compression & strength, turbo size & turbo system choice intercooled or not & the safety of the tuning work. Big CC Racing are happy to go in depth with you to help select your best turbo package to your budget.

ok what is involved price wise?

There are 4 main cost factors to turbocharging a bike. They are as follows….

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