re: Supercharge my GTV? Pt 1

[Jon Pike <jhpike@domain.elided>]

>OK, this kit is probably a bit of a joke, but it prompts a question that I've
>wanted to ask for a while -- why wouldn't an electric fan work to pressurize
>the intake charge?  There are some pretty powerful electric motors out there,
>especially DC motors.
>

I had a good laugh too,  when I saw that thing!

I don't know about how undersized "240 cfm"  would be for a Probe motor, 
 but I'll lay odds that thing
probably can't move 50!  Looks like a computer fan in a tube,  with tiny 
wires powering it.. probably
insufficent as a blower motor for your car's heating and cooling system. 
 And if it did make any significant
pressure,  that aluminum foil hose would pop..

On the idea of a functional electric "turbo",  it could be done,  though 
you have some tough requirements
to meet,  with high airflow AND pressure to be made.  That's another 
thing wrong with this picture,  it's a
simple bladed fan.  They can move a lot of air,  but as the back 
pressure builds up the volume goes down
very fast.  As in maybe 1-2 psi and 0 cfm.  You would need a special 
multi stage design,  or something resembling
a "real" turbine.

OK, so you get an appropriate compressor to drive with motors.. maybe 
half a real turbo,  and a big motor,
(don't forget a gearbox,  the turbine isn't going to do much for you 
under 20-50,000rpm)  you start getting into
how much horspower it will take to compress your air.  I'm not very sure 
what ballpark we're talking about,
but I've heard of superchargers needing 10-20hp (?) off the motor.  Say 
that's a big block Chevy,  and you
only need 5hp..  Ok, with motor losses you're looking at about a kW per 
hp,  so you need 5000 watts to drive
your motor.  That's almost 417 amps,  above and beyond your normal car 
load.  Still over 100 A at 48 V..
A starter motor is 1-2 hp, and not designed for continous use,  imagine 
how big the 5hp one would be,
not to mention the size of your alternator!

Wow.. this turned out even worse than I expected it to..  You really get 
to see how good a solution a exhaust
powered turbo is..  or a regular supercharger.   Unless my guesses on 
how much cfm are needed are way off,
and how much hp it would take to drive a blower,   I think we aren't 
going to see the "electric turbo" anytime
soon...

I could be off here..  Anyone know something about the relative cfm 
needed for various sized engines?  Or,
how much hp it takes to make a certain flow and pressure?

Jon

PS,  this guy should be reported to ebay for fraud...
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