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Discussion in 'PSI Superchargers Tech Questions' started by WIZBANG, Dec 22, 2008.
Does anybody know what the cfm rating is for this monster ?
9.8 Liters per revolution of the input/drive shaft.
Depends how fast you spin it.
It´s 0.346 cubic feet a turn
If you run it 50 over and rev the motor 8000 it would give you 4153 cfm or 70 cubic feet a second
Hmmm, so by numbers, the Whipple doesn't move as much air as a14-71 Hi-Helix ??? What it does is, not rob the power to turn it ???????
I'm interested to follow where this post goes. I'm not a math person..... What I do understand Whipple VS. 1471 HH is at the rpm and overdrive mentioned above, the whipple has the efficiency increased as RPM goes up and the 1471HH will have fallen off tremendously.
Does a 1471HH roots even compare to a screw (Whipple) anywhere in the boost spectrum? Thank you for any feedback.
The PSI is even less at 552 ci or 9.04565933 liters
9.8 liters = 598.032692 cubic inches
The explanation is pretty simple, sort of....
A Roots supercharger is an air "mover". When the lobes rotate, a volume enters the cavities and that volume gets moved to the other side of the case for use by the engine.
A screw charger is an air "compressor". When the lobes rotate, a volume enters the cavities, and then that volume gets compressed within the case, and finally that compressed volume gets moved to the other side of the case for use by the engine.
What that means by the time the swallowed stuff gets to the chambers, is the subject of dozens of books & texts & white papers.
Suffice it to say that a screw compressor is vastly more efficient at gathering and compressing and delivering a swallowed charge against prevailing manifold pressure (boost), and will result in more power within the chambers for reasons of superior VE and AE versus either the roots or the HH. That being said, there are both advantages and disadvantages between the screw & roots & HH. Depends upon the type of racing, and the fuel being used.
Yes, both the R980 and the A980 Whipple are theoretically 9.8 litres of displacement (swallowing volume) at "some" shaft speed versus boost pressure.
Superchargers, like turbos, have performance maps based upon pressure ratio (pressure across the device) versus shaft RPM and adiabatic efficiency (raise in temperature across the device) versus shaft RPM.
Then there's the mechanical efficiency and net power output, both of which are inferior to the turbo device..........
Sorry my bad, I was asking for cu in, not cfm.
Thanks for the asnwer !!!!!!!