Sophotrope

This is a compressor map plot of the Vortech supercharger which I understand is identical to the Paxton Novi 1220 which is in the SOS SC kit. I have drawn the travel of the compression/boost point as it travels along the rev range of an F20C with the stage 1 pulley. It's surprising to me that the path spends so little of the time in the high efficiency range (maybe only after 6k rpm). Is this expected? For 6psi boost I wonder if it would have been better to have a smaller blower...

soulicious

I think the better question is why only run 6psi, LOL.

s2000Junky

Sophotrope

I knew that response was coming. Fair. But even running 15 PSI doesn't put the line into the (large) central area. It seems to me like the Novi 1220 with ~1000CFM is more efficient on a, say 3L engine. There must be more efficient options for engines like the f20C which flows about 300CFM at redline.

Sophotrope

Here's a comparison with 6 and 9 psi boost on Rotrex c30-94. Looks better to my uninformed self.

Sophotrope

Ok here's rotrex 38-81 which is ideal it seems; way to do basic due diligence, Kraftwerks I guess.

beechx1

Is your line on the C38-81 graph a 6 PSI max line? The KW kits are typically making about 12 PSI using this blower.

Sophotrope

Right, I drew a (rough!) 6 and 9 psi line on that. Just wondering "if you wanted a very low key system, which blower would you choose?" That said, a 12psi plot on the 38-81 is going to look real good too. Pretty much right up the middle

Sophotrope

This is a little more accurate, 6, 9, 12 psi

beechx1

Something doesn't look right. On your C38-81 plot the 12 PSI line shows that a pressure ratio of 1.8 (about 12 PSI) occurs at about 65,000 rpm. But the blower is actually turning closer to 90,000 rpm when installed on the cars that make 12 psi.