I was wanting to know everyones opinion on the beastly little s/c's. Im planning on going s/c'd and Rotrex seems to be the best out there to my knowledge so what does everyone have to say on the matter?
i notice people making comments like it's not a centrifugal supercharger all the time... a planetary step up gear design(planetary system) does not make this a class of it's own... paxton made a planetary design in the 50's... it's not a new design, it's just a very little implemented design...
and if the impeller itself spun 4 times faster than other centrifugals it would fall to pieces, and make peak boost at like 2,000 rpm, because 4 times faster than normal would be like 200,000-300,000rpm depending on how hard you spin your motor.
there are 2 lobe, 3 lobe, 4 lobe, helical designs for roots blowers, but it doesn't qualify each of them to be something besides roots. this planetary step up gear system is just a nice design for gear multiplication from the input shaft to the impeller so it doesn't spin the same rpm as the engine... and this mulitplication is why peak boost is made so high, and the boost is a square of the given rpm it's at and why it doesn't make boost down low or mid range... you can change the gearing and make peak boost at different areas.
here is a link to paxton mentioning a planetary design http://www.paxtonauto.com/history.html
i think it's just the import world that thinks this is something new and special :dontknow:
they're pretty efficient up top... as you can see by the s2000 dyno on this page, the power doesn't peak early, whereas a roots style will make more boost/power low and mid range... i suppose a benefit would be low cylinder pressures while driving normally... but this shouldn't make too big of a difference since pistons have certain heat thresholds anyway.