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Old 27-11-2017, 11:03 AM
rotrex rotrex is offline
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Join Date: Jan 2014
Location: Germany
Posts: 187
Default Re: Nozzle spray angle...

positive displacement superchargers can be very noisy. They oscillate in several vibrational modes of their rotors and cases at certain rpm ranges. This is one of the reasons OEM installed positive displacement blowers are mounted in a pretty stiff way to the block or are heavily braced.
A particular example that suffers form this are the EP§ Jackson racing superchargers on Honda K20 engines. IT pretty much renders the knock detection useless in certain rpm ranges, IIRC some 5000-6000 rpm.

The Rotrex SC runs very smooth and is rather quiet compared to a roots type blower. Although with a cone type of open air filter the intake sounds like a jet fighter, a sound similar (same) as turbocharger intake noise.
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