Preparation for the STILLEN supercharger

stormcrow · 03-05-2010, 10:50 AM

Quote:

Originally Posted by Kyle@STILLEN

It was absolutely under 10 psi. Keep in mind that the dyno we showed was using the same kit that we plan on sending to CARB for approval. It would be pretty challenging to get a 10 pound kit through CARB.

So, then why not tout the PSI? What is the big secret? BTW, I don't see getting a 10psi kit past CARB. Vortech has already done it with some of their T-trim blowers, IIRC.

Really, what are we looking at here? More or less than 8psi? This question can be answered without giving away the 'trade secret'.

Quote:

Originally Posted by RCZ

You can do it with less than 10psi.

You are getting mixed up with spooling time vs. size of a turbo charger when looking at that graph. A sc's size has nothing to do with when it spools, it is mechanically driven, so what you want to talk about is power delivery and the ramp effect of the gearing within the scharger.

Easily explains it? The similarities with a turbo is in the way power is delivered. Since it is a compressor wheel, it will compress more air the faster it spins, like a turbo would as it spools up. That's about where the similarities end though because there is no hotside wheel that needs to be spun and spooled by exhaust gas...

Are you kidding? Of course an SC's size has to do when it spools. Bigger compressor wheel, less CFM at lower RPM. Hence the reason why you can change either the pulley size that drives it OR the compressor size, itself, to change key aspects of air delivery. It really doesn't matter if drive is coming from a belt or from exhaust. Key physics do not change.

Analogy - A bike wheel spun by a chain and crank. The larger the wheel, the slower its rotation at a given speed of crank spin. Change to a smaller wheel and what do you get? Faster spinning wheel. Now imagine these wheels are compressor fans...which is going to produce more CFM at a constant lower speed or as the RPMs ramp up? The truth is, it takes the larger Vortech more RPMs to push the same CFM as the smaller compressor of the Rotrex at lower RPMs. It's not a huge amount, but definitely significant enough to show the differences in torque. The plus side of this? More power to be had when running higher boost as the larger blower will not run out of steam as quickly.

And, I don't think anyone at Stillen would disagree.

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