Here's the actual boost levels of the Rotrex C30-94 Supercharger as measured by Sper Scientific meter just before the throttle bodies (post intercooler). The boost is actually a lot less linear than I expected, but there is little loss at 7000 RPM due to intercooler. The C30-94 is rated at 1 BAR boost at 7000 RPM, so the measured .935 BAR boost would seem to indicate that intercooler friction cuts boost by about 6%. I don't have an intercooler in temp yet, but IAT before throttle bodies was only 77F on a 70F day with fan blowing on intercooler. That's a respectable (and worthwhile) IAT given the boost levels.

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It looks good. Quite a bit of air flow, must make for a white knickled ride.

I don't understand why you would expect the boost to be more linear from a centrifugal compressor. As impeller speed doubles, mass flow will square.

Have you checked boost prior to the intercooler? Don't rely on rated flow numbers, measure it if possible. Have you checked air temps pre and post intercooler?

By any chance, have you checked the temp of the compressor gear housing at higher rpm, or just after a pull? I am curious how much the planetary gear drive heats up at higher speeds.

Good point, WT. I knew the boost would be somewhat curvilinear, but I was expecting a flatter curve. When I install the fitting for the intercooler IN temp sensor, I'll also place a fitting to measure the boost pre-intercooler. BTW, thanks for the tip on the SPA gauges... I'll be installing their very cool "Intercooler In-Out Temp" gauge. We shot the SC housing with the IR gun while dyno tuning, but I didn't write down the reading, and have forgotten... will record next time.

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