downwardspiral

twincharger

This is all it says, doesnt really get into how it works though.

waxyourboard

hahaa! i like how it's '0 to 60' is still 7.9 seconds!

Anyways, in that article it says that when the turbo starts to kick in, the supercharger begins to disengage. It doesnt say start to 'fade off' possibly the suepercharger pulley is being run with a clutch-type pulley... kinda like an a/c compressor, sometimes it's on, sometimes it's off.

If it's not like that, i dunno, i'm not a pro on this... but because the boost on a centrifugal charger is created in the housing, there's more pressure given in the same volume of air... and your roots/twin screw type superchargers depend on volume of air, it would still increase the pressure of the air... it'd be the same as running just a turbo at regular air pressure. Or running a supercharger at one and a half times air pressure. (ex. sea level, or a mile + up... boost levels do increase their psi (1 atm = 14.4 psi appx = sea level)) There is more pressure being created, but still the same volume of air being delivered (more molecules in the same amount of space)




oh, and i found out why centrifugals can run more psi.. quote from the strokerengine.com... "the total effective CR (compression ratio) occurs at max boost, a level that's reached only at higher rpm where there's less engine loading."
So because there's less resistance on the engine, you can pump up the boost without causing detonation. (like revving the engine in neutral)

angcobra

It is quite common in the idustrial world to have engines that have both superchargers and turbos. Many Fairbanks Morse Diesel engines used for trains use twin turbos feeding into a shaft driven supercharger. The power plant I worked at had 5 backup Diesel Generators each had twin turbos with aftercooler fed into shaft driven supercharger.

wayleft

okay my understanding is:

roots type push air through the motor(also called Positive dislacement)

centrifugal types compress air to higher than Standard Pressure(14.7) and add that air to the air that natural pressure pushes in.

Twin screws do both they push compressed air through(positive displacement)

If Im wrong please correct me.

Vash the Stampede

personally i like how rootblowers sound.. even on the new Cobalt SS hahha

but if it was up to me.. i will defintly get centrifugal or a turbo. because you don't always need power.. unless your gunning it. which is what a centrifugal would do perfectly. and do it well

OnyxCobra

roots style blowers arent always giving u the power either, just when u wail on it its already right there pushing full capacity.

angcobra

The purpose of all SC and turbos is to provide intake air at higher than atmospheric pressure. In theory boost equal to twice the atmospheric pressure (14.8) will double the HP of a engine from when it is NA.
Roots and twin screw are both positive displacement, which means you get a set amount of air volume per revolution of the SC. The benefit of this is always having compressed air (boost) even at low engine RPM. The twin screw is more efficient than roots so it will perform better at high RPM.
Centrifugal provides increased air volume per revolution the faster it turns up to it's maximum efficency. Not much boost at low RPM but more boost the faster it turns. Many race cars prefer the centrifugal because less boost (HP) is made at the start to help with traction but as soon as the car is moving and the RPMs go up the boost (HP) is also up.