OK, I've been reading Meuller's crap too long, Just little bit of boost Options

[DNHunt]

How about a small electric compressor directly in the intake that runs constantly to provide a small amount of boost maxing out at say 4 psi. Boost is regulated by a stepper motor controlling a very small wastegate or very large idle air control valve. The stepper is contolled by the ECU using input from the throttle position sensor. Not much compression of the air and it could come from a cold air intake so no intercooler. It's pretty simple electronics. Would it work and is it worth the trouble?

Fire away (IMG:http://www.914world.com/bbs2/html/emoticons/ar15.gif)

Dave

[jsteele22]

I think the weak link with the electric supercharger idea is the cost.
And the cost is driven by the sheer size of the numbers involved.
The energy is stored in a bank of (heavy, expensive) batteries. During the several seconds of fun, you've got several 100's of amps flowing through some fat cables. Then once you're cruising, the system gradually kicks in the special high-current alternator required for such a massive store of energy. So even without the control system, there are several heavy, big-ticket items. Anybody that tries to stick a CPU fan in a rubber hose has missed the main point : to get more output power, you've got to expend a proportionately large amount of energy/power to get enough air compressed. So while a well-designed electric supercharger sounds like a very cool project to tinker with, if you just want a lot of power for a little $, keep looking.


I do like the idea of gradually storing up energy that gets used only during the comparatively rare times when boost is really needed. But converting mechanical energy into electricity, then storing the electric energy, then converting that back into mechanical energy is very, very wasteful. One idea that might be fun to play around with is using compressed air. An A/C compressor could gradually pump up a bank of gas cylinders (okay, so a 914 might not be ideal for this...) and the gas could even be cooled to increase the density (like normal intercooling, but done ahead of time). Then open up a valve on a big pipe to let the fun begin. But once again, this would be a pricey, novelty sort of setup that even more plainly begs the question : why not use nitrous ?