[Chasfield]

I have often wondered if low pressure electric supercharging is feasible.

These folk say "yes":

http://www.electricsupercharger.com/

These people say, "kind of, up to a point":

http://www.streettostrip.com/content/view/41/40/

Intriguing, but you need to be able to furnish 60 amps to get 1 PSI boost. At the bottom of this page there is mention of some guys who bolted a garden leaf blower onto a Honda Civic's induction system and got themselves a twenty horsepower gain.

That would spoil the lines of my Bullet though.

 

[ace.cafe]

Yes of course, in theory it is possible to electrically supercharge.
Aftr all, any supercharger is a mechanically-driven device that could be driven electrically if the power of the electric motors is strong enough.

The matter of a fan doing this is quite different, but a small amount might be possible, such as the E-Ram product claims.
They claim 4-6% gain.
The fan motor uses 1 hp, at least, in electrical consumption.

So, let's say we look at the Bullet.
What's 5% of the Bullet power?
A normal stock Bullet produces about 16hp at the rear wheel.
5% of that would be about 3/4 of a hp.
Okay, let's look at a typical Bullet like most people ride, with a free-flow exhaust and free-flow air filter, with a carb re-jet. That's about 20hp.
5% of that is 1hp.

So, assuming we actually did get the 5% gain that they claim, and could find some way to get our alternator to produce about 10 times more power than our alternators can put out, we could get 1hp out of it. And that also would equal the approximately 1hp of electrical consumption that it would take to power the electric fan.
This yields a net gain of zero.

However, if we had a 5-liter engine and got maybe 15hp out of the fan system, then the 1hp loss from electrical consumption might be more negligible. But in our case, we only get one hp out of it, and it takes one hp of electricity to power it, so for us it's useless.

However, this is not to say that improved air pressure in the airbox is useless.
It is known that almost all air intake systems with filters cannot maintain full atmospheric pressure during hi-demand riding such as racing or wide-throttle applications.They actually run at a few psi less than atmospheric, because the engine is sucking in air so quickly that the rest of the intake system can't keep up with demand, and the result is that the airbox runs at a few psi below atmospheric pressure, which impairs the ability of the engine to breathe by some percentage.
Simply by bringing the airbox up to normal pressure, and alleviating that few psi vacuum depression in the airbox, can give a similar result of power increase WITHOUT any actual boost of pressure over atmospheric.
This is the type of thing that a Bullet could gain from.
And that is achieved simply by keeping the airbox from going lower pressure than atmospheric. it doesn't require "boost" to achieve some gains, in most cases.
And basically, that is how "Ram-Air" works. Ram-Air doesn't really provide any "boost". It just helps to give enough pressure into the airbox that it doesn't go negative below normal  atmospheric pressure. And it works, and you can feel it.


Now, for the "leaf blower" thing.
We certainly couldn't power an electric leaf blower off our alternator either.
BUT...
if we were to use a gasoline-powered leaf blower with a little 2-stroke engine running it, and used that for a supercharger, we wouldn't be taking any power away from our engine.
So, assuming the gas-powered leaf blower had enough air output to work, and it is "self-powered" with its own engine, then we might see something out of that.
And if we were to hook-up some sort of variable throttle to the leaf blower engine, which corresponded to our motorcycle engine throttle cable, we could "tune" the output of the air from the leaf blower, so that it progressively blew more air into our engine as the throttle positions got further open.
I think it woud be a little "wierd", but it could probably work if you wanted to strap a gas-powered leaf blower to your Bullet.

[luoma]

Check out this interesting turbo-type concept at www.mindblowerchopper.com

Don't know if it really works ot not, but it should at least reduce restriction at intake. I guess f a hood scoop works, this should.

[luoma]

Didn't know Ace was posting at the same time I was. Looks like he's got it covered.

[Ice]

How about a leeetle squirt of Nitrous and a one of those intel a jet things 

[Vince]

     I just eat beans and sit near the air intake.

[cyrusb]

As Ace says, just getting the airbox pressure to atmospheric would be a gain, and I bet the leafblower would more than do that. But to go on to higher pressures would require you to pressurise the entire carburetor with some kind of leak tight enclosure. A real pain in the ass to do.Without it the fuel just squirts out the vents.

[Chasfield]

I guess somebody must have analysed the benefits of very low pressure supercharging and if it was a no-brainer it would be a standard fitment by now.

Intuitively though, you might expect that slightly pressurising the induction system, via an electric supercharger with much more modest current draw than the 60A quoted for 1PSI, would at least drive volumetric efficienty towards the desireable 100%. That is, it would overcome the imperfect aerodynamics of the internal surfaces of the average indcuction tract and aid cylinder filling at low rpm, particularly during the early stages of the induction stroke, when the piston is moving too slowly to do much useful breathing in.

Clearly, to acheive even 1 PSI of proper visible boost (~107% volumetric efficiency) is a whole different ball game.

[The Garbone]

Leaf blower?   If you use a chainsaw to run the supercharger it would be easier to set up.   Already has a sprocket to attach a chain and variable throttle,  all you have to do is get a 2 cable throttle setup for the bike an rig the connection.

[ace.cafe]

I guess somebody must have analysed the benefits of very low pressure supercharging and if it was a no-brainer it would be a standard fitment by now.

Intuitively though, you might expect that slightly pressurising the induction system, via an electric supercharger with much more modest current draw than the 60A quoted for 1PSI, would at least drive volumetric efficienty towards the desireable 100%. That is, it would overcome the imperfect aerodynamics of the internal surfaces of the average indcuction tract and aid cylinder filling at low rpm, particularly during the early stages of the induction stroke, when the piston is moving too slowly to do much useful breathing in.

Clearly, to acheive even 1 PSI of proper visible boost (~107% volumetric efficiency) is a whole different ball game.

Chasfield,
That's exactly what I'm doing with my ram-air induction system that everybody makes fun of, because it looks like a "cannon barrel" sticking out into the airstream on my bike.
However, it actually does produce the results that you describe, and I had to significantly change my jetting to suit, and I can feel the power increase from it.
You don't need a blower to get that done.
But, you need to have an air intake scoop or duct, and people don't seem to like the looks of what I made for my bike .But it damn sure works.
From my point of view, it doesn't look bad, and I really like the added torque and hp that it provides on my basically stock Bullet.
And I will have an enhanced version of that on my Ace Fireball Bullet when I get it done.
I figure it's worth about 2-3 foot-pounds of torque, and 2-3hp. I can really feel it in the midrange, big time.
It starts to look a whole lot better after you've passed a 53' truck on an uphill grade on a 2-lane highway at 65mph!

[Chasfield]

I guess free air is like free beer - might as well drink it.

 

[Darth Sid]

A ram air intake is definitely an inexpensive supercharger but aesthetics do get disturbed. Does that intake really need to be that wide and that far to the front?

[ace.cafe]

A ram air intake is definitely an inexpensive supercharger but aesthetics do get disturbed. Does that intake really need to be that wide and that far to the front?

No.
It could be smaller and shorter.
But it needs to have the entry forward of the engine in order to get cool air, and far enough to the side to be in the direct air stream. And if it's narrower, it doesn't provide as much pressure.
It all depends on how well you want it to work, and how much room you have, or are wiling to accept.