Centrifugal supercharger question?

Question

 

i cant figure this out.
i understand turbos very well, but Centrifugal superchargers i cant figure out.

i was looking at vortechs site and looking at their charts. it shows their lowest one makes 550hp.

now i want to put one on my miata 1.6L. am i over complicating this. because i dont think i can get 550 hp out of this. im thinking you just swap the pulley to increase boost. and if it can make 550+ on a v8 why couldnt it make the same on a small 1.6? it should cram the same amount of air in the engine to burn so it should be able to make the same power.

is this right? if so could i get a “V-1 Si-Trim” and make 600hp with that little engine? you know after its built and tuned?

please clear this up for me its frustrating me! one side of me says that yes it can. then the other side is saying its not possible.

thank you.

 

Answer

 

Vortech rates their superchargers on what the max power it will support is. So an Si-Trim will support UP TO 550hp. If you want to make more than 550hp, you would need a bigger unit. Just like a turbo, you can change the boost presure that is output. Only difference is, you can’t just turn a screw or push a button to do it, you have to swap 1 or more pulleys. Just like a turbo, the power made is an effect of volume, not pressure. 15psi on, say my 4.6L V8 might be 45-50lb/min of air, which is roughly 450-500hp, but 15psi on the B6ZE in your Miata might only be 28-32lb/min, or 280-320hp. This of course means that the pulleys for the supercharger on your Miata will make the supercharger turn slower than on my V8 at the same psi, but with the same size crank and blower pulleys, it SHOULD move the same amount of air, and thus make the same amount of power on both engines.

EDIT: In response to BigeQ’s answer, uhhhh, no. A centrifugal supercharger doesn’t make boost quicker than a turbocharger. Sure, you might have 1psi at 1500rpm when the turbo is still in vacuum, but by 2500rpm, the centrifugal might only be at 3psi while the turbo is at 7. Centrifugal superchargers build boost as RPMs increase, so they don’t make the max boost until redline. Turbochargers (properly sized) will make peak boost earlier in the RPM range (before 3000rpm hopefully) and hold that pressure most of the way to redline, tapering off slightly until redline. Positive displacement superchargers make peak boost nearly instantly, and slowly taper off all the way to redline.