Electric superchargers

[bert]

Hi all,

Just wondering if anybody has had any experience fitting an electric supercharger to a VW and what their findings were.

http://www.force-flow.com/info_x4brushless.aspx

Seems sound in theory, especially at wide-open throttle. Not sure about their claims that it improves fuel economy when it's not operating (whenever foot is not to the floor).

Also their Fuel Saver device seems iffy to me from a thermodynamics perspective. http://www.force-flow.com/ff_turbine.htm

However they are an Aussie company and seem to be somewhat legit, could be a way to reduce turbo-lag for those serious about their 0-100 times... Or it could be a complete crock...

[gareth_oau]

hey blue_reality, perhaps a new project for mightycarmods?

[BL33SU]

hahhaha dnt bother

[Manaz]

Or it could be a complete crock...

This is where my money is.

A "regular" (PD or centrifugal) supercharger takes a not-insignificant amount of power to drive it hard enough to provide sufficient boost that it's worth installing. Any electric device would likely need to have a similar mount of power (provided as electricity rather than kinetic energy from a belt) to provide the same sort of boost. And that means taxing the electrical system pretty damned hard - harder than any of the electrical supercharger devices I've yet seen could possibly run (given their size/design and the electrical systems in most cars).

[The_Hawk]

I have read a few things lately about these topics, one in the Club VeeDub mag with an excerpt from Popular Mechanics, another about an Australian product watchdog.

In short the Australian group removed a number of "fuel saver" for sale in Australia as they didn't do what they claimed at all, a number of others had to change their product descriptions. They went onto say none of the devices they tested actually did anything useful.

Popular mechanics tested a bunch of fuel savers, again in short, those that went into the intake caused less power and less torque (one actually stopped the car from running). If I remember correctly it was something like a 10 - 20% REDUCTION in power and economy. The ones that did the "best job" had some sort of 'magnetic' effect or similar and stuck onto the airbox or intake pipe or fuel rails... by best effect I mean it didn't actually impede performance... Didn't help either, but at least you didn't loose anything. They went on to say, that while it may sound crazy, the car companies are not keeping some magical secret that will give you better economy up their sleeve for a rainy day.


As for the electric supercharger. In theory it could work if it could spin fast enough, but there is a good chance that it will do little other than impede the flow of air in the intake, especially at full throttle when even a NA engine can suck down insane amounts of air all by it's little self. Once again, long story short, chances are it will hinder, not help.

[gareth_oau]

Brockie must be turning in his grave, all these tryhards failing after his very successful 'polariser'

[chockz]

IT DOES NOT WORK! DO NOT BOTHER!

Why am i so sure abt this?

coz i tried one on my previous car (civic) =(


chock

[Greg Roles]

Problem is to actually deliver the HUGE amount of air that a typical engine flows, the motor has to be pretty magic, and the power consumption is going to be HUGE. Even mythbusters tried this with a air broom, and it was a restriction even flat out.

From autospeed:

The amount of air that flows into the cylinder, compared with the cylinder volume, is called the engine's breathing - or volumetric - efficiency. In a 3 litre six cylinder engine, each cylinder has a swept volume of 500cc. If the cylinder breathes in only 400cc on the intake stroke, the engine is said to have an 80 per cent volumetric efficiency (ie 400/500 = 0.8 or 80 per cent). Volumetric efficiency will depend on lots of factors (including how well the ports flow), but let's say that the VE of the example engine is in fact 80 per cent. If this 3 litre engine is revving at 6000 rpm full throttle, this means that it inhales 7200 litres of air per minute (remember, one intake stroke per two rpm), or 120 litres per second. To put it in different units, each minute this engine consumes 254 cubic feet of air. To put that into context, a little 60mm diameter PC cooling fan flows only about 18 cubic feet per minute. So, just to flow the amount of air that this naturally aspirated, 3 litre engine needs, you'd need an array of fourteen 60mm fans working flat-out. And that's without creating any boost at all....

Nothing on e-bay will do anything but actually BE a restriction.

Having said that, there are serious versions out there, at serious prices....

http://autospeed.com/cms/title_Elect...3/article.html

[marinemw]

It works

Bert
I have one of the original "force-flow" units, it draws approx 42amps and makes 4hp at the back wheels difference on a dyno. Its on my Lotus 7 with a 4age twincam, a cheap power gain and it works.
Rgds

[The_Hawk]

Having said that, there are serious versions out there, at serious prices....

I was just running the numbers for a VR6 @ 80% VE and I get this

Revs 	CFM
500	19.8
1000	39.6
1500	59.3
2000	79.1
2500	98.9
3000	118.7
3500	138.4
4000	158.2
4500	178.0
5000	197.8
5500	217.5
6000	237.3
6500	257.1

I then look at something simple like this:

http://www.sidewindercomputers.com/deaf12recgrh.html

(Here is also a smaller alternative:
http://www.jaycar.com.au/productView...T&SUBCATID=725 )

Yeah it's for a PC and I don't know if it will carry and actual pressure, but theoretically with the right adaptor plate it is damn close to delivering the required air at redline. I wonder if it were turned onto 100% all the time if it would provide some boost down low, then not hinder redline power...

wait... it's only capable of a maximum pressure of 27.48mm H20 or 0.039PSI...


So we can get the air moving at speed, but need to get something with enough torque behind it to actually drive it at pressure.

Isn't maths interesting!

[Manaz]

Axial fans (where the air flows out along the axis of the fan motor) are also terrible at producing static pressure (hence why they'll flow a lot in an open space, but not if you start putting restrictions on the intake/exhaust side of things).

Cage/squirrel fans (where the air flows out perpendicular to the axis of the motor) are better at producing pressure, but generally don't flow as much cfm in free air as axial fans do for a given power draw).