http://www.turbomagazine.com/tech/0406tur_knight_turbo_electric_supercharger/

This one will flow enough air for a small engine.
But look at the setup. Not exactly a $39.99 undertaking.
Current draw for a large engine will be tremdous...

A tube with a little fan on it will not flow enough air for an engine.
That's why blowers have industrial-strength rotors, screws or impellers to compress enough air.

 

Manifold pressure less than 7 PSI is merely a "blown engine" or "boosted". The term "supercharged is an engineering term and technnally (SP?) Ford is wrong but the word supercharger sells more than the word boosted.

A device driven mechanically by the engine to boost manifold pressure would be called a blower.

 

OK... interesting. I would have figure blown was more having to do with drag cars and their roots set ups. Boosted does bring back memories of being a child to big to fit in a high chair, but not big enough to eat sitting in a chair.

The things you learn.

-Kerry

 

I just call any engine running over atmospheric pressure (ambient) "a forced induction engine".

I'll let others define and argue specific terms. Me, I'm gonna make stuff

 

So Frederic, from seeing your posts on other threads, I know your a think it through WiZ (pat on back smiley inserted here). Do you know how to determine how much horsepower would be loss through alternator/electric motor vs direct drive super. Would there be any benefit whatsoever to be able to modulate the compressor wheel RPM's seperately from engine RPM's? One benefit would be the availability of "full boost" at extremely low RPM's. Of course the electric motors would need brakes on them so not to overboost so severly on deceleration.

It could become quite controllable to go with an electric system, but would it have any advantage?

TG

 

Electric supercharger! If you want more power, just strap on a leaf blower.

http://videos.streetfire.net/search/...ad23ca9564.htm

 

haha i wish i had a dyno. that video was sooo cool.

 

hahahahahahahahahahahahahaha....suprised they didnt blow the welds on there intake with all that boost and nawz man.

That gave me a crazy idea tho...you could make a go-cart with a leafblower engine and plumb the blower into the intake of the engine. It would work!

 

to figure horse power loss of the electric blower you would need to know several factors . first you would need to know current draw (amperage )of the blower motor at full boost this will be affected by engine rpm and effeciency due to resistance to the fan once the fan actually compresses air motor load will increase and will make current draw vary .so a hypothetical set rpm on the engine and blower motor would need to be used so amperage would stay constant . then you would need to know magnetic draw (clamping force ) of the altenator when supplying that amount of current (more current draw more clamping force ) this then could be then converted to hp or torque .

 

Sorry I missed your reply. This thread came back as "read" for days, then today it appeared as "unread". So, I never clicked on it.

Converting rotation energy (crankshaft) to electrical energy (via alternator) has losses associated with the conversion. While alternators have bearings, there is some friction, and this friction results in heat - which is energy that is not being utilized to make electricity.

Converting electrical energy (from alternator) into rotation energy (motor rotation) suffers from the same problem - friction, but also motor design, number of poles, all sorts of things, so there are a lot of inefficiencies with this conversion as well.

A typical, average, run of the mill belt-driven supercharger typically takes about 10% of the crankshaft's HP for itself. So if you have a 300HP engine, 30HP of that is going into the supercharger to achieve a reasonable level of boost.

To achieve whatever boost level the above results in, we can calculate backwards what the alternator --> electric motor has to do in order to achieve the same thing.

Since 746 watts equates to 1 horsepower... and we need 30HP in my above example...

W (watts) = V (volts)* I (amps)
746W = 14V * I
53.29A = I

For each HP we need to drive the electric supercharger, we need 53.29 amps. So for 30 HP in my above example, you need 1598.7 amps going into the motor.

We're not done yet

I did an experiment a while back whereas I tried to calculate the losses of an alternator driving a motor, to determine the power going in versus the power going out, and with the junk I used I approximated the loss of the two things together to be in the 50% range. So if that is in fact true, that means you really need about 3200 amps to drive an electric supercharger to the same boost level as an ordinary, belt driven supercharger.

Now, you have two choices. You can say holy s--- and not think about it again, or you can think about this a bit more.

If you did size an electric supercharger that big, you don't have to run it off the alternator - instead, you could run it off large battery banks the way some of the competition-class audio guys do.

A typical car battery can provide say, 500A of cranking power for the starter. You could have several of them in parallel, so that for a short time anyway, you could drive an electric supercharger for that short time. Then disengage things, and recharge the batteries when you don't need boost.

Very doable, in fact these types of experiments have been done in the past 40-50 years or so - it's not a new idea.

It's just a really complex, difficult to manufacture reliably and affordably, type idea. But it's reasonable and doable if you have the means and energy.

Personally, simplicity is wonderful. Supercharger with a belt, providing boost all day long when you mash the pedal with your right foot.

Actually, I prefer turbocharging for a variety of reasons, but I won't go into that since that's not addressing your question. But in a nutshell, that's how you calculate the power required to drive an electric supercharger.

Essentially it comes down to "a heck of a lot".

Top fuel funny cars for example, which produce what, 8000 HP or something insane like that? Easily expell 800-900 HP to drive the huge supercharger on top of the engine. If you were to watch the engines run on a dyno, in extreme slow motion, you'd actually see the belt stretch on the take up side and slap around on the other side... almost an inch. Imagine the power involved to stretch a 3" or 4" wide rubber belt with fiberglass or metal wire reinforcement, a whole inch. Coincidentally, it's about 800-900 HP, or about 600KW of energy.

Hope that helps!

 

I use a leaf blower on my engine and get better results but the cost of extension cords is killing me

 

CPR is my local Speed Shop. Those guys are nuts...

 

you might as well change out the blinker fluid while your at it and get new spark plugs as well... LOL

 

i found that blinker fluid for ya too!

 

well frederic, i'm still cuttin the grass w/the old 70's-ish snapper w/a kohler mabey a a 12-71gmc would look pretty good hanging off the side. think you could think me up a manifold solution??