I have been doing some research for a while and trying to find the best way forward for my build to give increased but useable power.
Functionality that is important to me is:
One good post I found was on Hayabusa.org in reply to a question about "Pro's & Cons of a Supercharger". Seems quite balanced from someone who sells both solutions.
Post reads:
" I both turbocharge & Supercharge motorcycles for a living. When you compare the two there is a lot in to take into account.
The Superchargers just like Turbochargers come in various shapes & sizes but on road going motorcycles there are only two truly available ones that work effectively. The Rotrex & the Procharger. The Procharger will make more beans at the same level of boost because it is relying on moving volumes of air rather than the speed of air. The turn ratio in the procharger is less than the faster Rotrex but the Rotrex does not have as big an impeller or as big a scroll or as big an inlet & it does create more heat through the fact is moves less air faster. The Rotrex is much quieter & a lot easier to fit as the prochargers are more bulky. So they both have their plus points.
With both these types people should not fool themselves by comparing to the old wipple & roots style units that give instant boost. These are in effect turbo impellers driven through gearboxes & a belt from the end of the crankshaft. Neither in a decompressed engine make any more than a stock motor upto 3500 to 4000rpm on a Busa nor do they make any more low down than a correctly sized turbo. The reason is the airflow needs to build via rpm speed to a suitable level where the engine turns from vacuum to positive.
Superchargers are hindered in daily use by the requirement to adjust belts, & replace pulleys, & engine seals & bearings all of which have to be designed to rotate at 11,000rpm under load.
Yes superchargers loose power in their driving by the force needed to rotate the unit.
Superchargers boost all the time after going positive from vacuum. You have to think about this. It means if you are accelerating quickly or slowly or constant cruising or even decelerating or bashing down the gearbox going into a bend the boost is linked with the rpm & thus it is boosting even on deceleration though it may be vented off the hot air is still there...
That is the principal reason why I would never consider bolting a Supercharger to a stock engine they heat soak & are more liable to give engine failure due to the increased boost usage. A turbo by comparison only boosts when you load it. In other words pull the the throttle back. You can red line a turbo at 10% throttle & make no boost at all & obviously at a cruising speed on roads it remains off boost.
This then means that the turbo can be mapped with much less fuel usage than a supercharged engine as the enriched state only needs to be when it is generating boost which unfortunately for the supercharger is every throttle position from 3500 onwards.....
Supercharged engines will naturally make more exhaust noise than turbo engines. A serious consideration at certain race tracks. This is because the increased exhaust gas from aspirated is unchecked & at a higher level, so if your aspirated engine was marginal these will be mucho noisier on the exhaust. The turbo naturally quietens the exhaust by the spinning of the impeller.
Turbos can be linear in boost delivery & should not suffer lag on motorcycles. If yours does then you are using the wrong size or something is crap. if you feel you need immediate power from a set of lights just put it on full throttle & lob the clutch. You will soon realise its too quick anyway when its flipped over backwards. Superchargers do have that instant feel on the throttle that a turbo does not have.
When comparing supercharger power with turbo it is important same as in rotrex v procharger to do it boost level for boost level. Remember with the turbo you can just add more boost by a controller without the need to swap pulleys. You will find the all important inlet temp is much worse on the superchargers than on the turbos this again will restrict the boost on usable road fuels & the power potentials."
Functionality that is important to me is:
- Linear power delivery
- Target power of 350 wheel hp
- Good torque low down in the rev range
- Reliable and safe power
- Option of different maps to load in to the MBE ECU
- Ability to adjust the power level based on conditions with switchable boost
- To put the power down to the road in a controlled manner with minimal wheel spin
- To be able to drive at motorway speeds off boost
- Modulate boost based on throttle position up to full boost
- To be able to increase the power in the future if required
- Quiet enough for Track Days
- Fast enough to scare me
One good post I found was on Hayabusa.org in reply to a question about "Pro's & Cons of a Supercharger". Seems quite balanced from someone who sells both solutions.
Post reads:
" I both turbocharge & Supercharge motorcycles for a living. When you compare the two there is a lot in to take into account.
The Superchargers just like Turbochargers come in various shapes & sizes but on road going motorcycles there are only two truly available ones that work effectively. The Rotrex & the Procharger. The Procharger will make more beans at the same level of boost because it is relying on moving volumes of air rather than the speed of air. The turn ratio in the procharger is less than the faster Rotrex but the Rotrex does not have as big an impeller or as big a scroll or as big an inlet & it does create more heat through the fact is moves less air faster. The Rotrex is much quieter & a lot easier to fit as the prochargers are more bulky. So they both have their plus points.
With both these types people should not fool themselves by comparing to the old wipple & roots style units that give instant boost. These are in effect turbo impellers driven through gearboxes & a belt from the end of the crankshaft. Neither in a decompressed engine make any more than a stock motor upto 3500 to 4000rpm on a Busa nor do they make any more low down than a correctly sized turbo. The reason is the airflow needs to build via rpm speed to a suitable level where the engine turns from vacuum to positive.
Superchargers are hindered in daily use by the requirement to adjust belts, & replace pulleys, & engine seals & bearings all of which have to be designed to rotate at 11,000rpm under load.
Yes superchargers loose power in their driving by the force needed to rotate the unit.
Superchargers boost all the time after going positive from vacuum. You have to think about this. It means if you are accelerating quickly or slowly or constant cruising or even decelerating or bashing down the gearbox going into a bend the boost is linked with the rpm & thus it is boosting even on deceleration though it may be vented off the hot air is still there...
That is the principal reason why I would never consider bolting a Supercharger to a stock engine they heat soak & are more liable to give engine failure due to the increased boost usage. A turbo by comparison only boosts when you load it. In other words pull the the throttle back. You can red line a turbo at 10% throttle & make no boost at all & obviously at a cruising speed on roads it remains off boost.
This then means that the turbo can be mapped with much less fuel usage than a supercharged engine as the enriched state only needs to be when it is generating boost which unfortunately for the supercharger is every throttle position from 3500 onwards.....
Supercharged engines will naturally make more exhaust noise than turbo engines. A serious consideration at certain race tracks. This is because the increased exhaust gas from aspirated is unchecked & at a higher level, so if your aspirated engine was marginal these will be mucho noisier on the exhaust. The turbo naturally quietens the exhaust by the spinning of the impeller.
Turbos can be linear in boost delivery & should not suffer lag on motorcycles. If yours does then you are using the wrong size or something is crap. if you feel you need immediate power from a set of lights just put it on full throttle & lob the clutch. You will soon realise its too quick anyway when its flipped over backwards. Superchargers do have that instant feel on the throttle that a turbo does not have.
When comparing supercharger power with turbo it is important same as in rotrex v procharger to do it boost level for boost level. Remember with the turbo you can just add more boost by a controller without the need to swap pulleys. You will find the all important inlet temp is much worse on the superchargers than on the turbos this again will restrict the boost on usable road fuels & the power potentials."
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