classciv

just saw this thing on ebay that is an electric supercharger that hooks up on your intake manifold. and then they say there is a switch to turn it on at full throtle. just wondering if anyone has tried them out or knows what the deal is, they are selling for around $100 and say they give 50 hp. ????? true or not ?????

NJIN BUILDR

They do make power adding electric superchargers but the price is closer to $3000.The cheap ones only get in the way of airflow.
Glenn

classciv

thats what i wanted to know, because if you have to turn it on when the throtle is wide open, what is it doing when the throtle is not wide open, and it is shut off?

Turbo E

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by classciv &raquo;</TD></TR><TR><TD CLASS="quote">just saw this thing on ebay that is an electric supercharger that hooks up on your intake manifold. and then they say there is a switch to turn it on at full throtle. just wondering if anyone has tried them out or knows what the deal is, they are selling for around $100 and say they give 50 hp. ????? true or not ?????</TD></TR></TABLE>

500 posts and you're still asking questions like this????

anyways. no

classciv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo E 604 &raquo;</TD></TR><TR><TD CLASS="quote">

500 posts and you're still asking questions like this????

anyways. no</TD></TR></TABLE>

if you think about it, it makes sence, basically i was asking to see if anyone had tried them out to see what effect they did have, or if there was a cheeper supercharger setup that actually did anything at all. never hurts to ask questions, although i usually dont because for some reason people like to post things that have nothing to do with the question itself.

Chris F

If you do the math, you need a ton of power to push air in the intake at a high rate and a high pressure, even at perfect efficiency. Dozens of horsepower (tens of thousands of watts). You'd need an electric motor drawing 1,000 amps to get close to the power of a normal supercharger or turbo.

Gotta pay to play...

-Chris

Chris F

Math is fun.

cfm = (cid)(rpm)(0.5)(Ev)(Pr)/1728

Assume you have a 1.6L civic. Round it up to 100 cid.
RPM we'll say 7000, towards redline.
Ev = .85 efficiency
Pr ... if you want 0.5 bar (7.3 PSI) of boost, that's 1.5 pressure ratio.

You have 258 cu. ft. per minute. 446250 cu in per minute. <U>Intake flow is 7437.5 cu.in. per second.</U>

Assume perfect (100% efficiency) air pump, and calculate power needed to pump it at 7.3 PSI. 7437.5 in^3/s * 7.3 lb/in^2 = <U>54293.75 lb-in/s</U> (This calculation is pretty rough... it depends on the size of your charge pipes etc..)

Convert it to HP... (google is a handy converter)
http://www.google.com/search?h...in+HP
54 293.75 ((pound force * inch) / sec) = 8.22632576 HP

Convert it to Watts...
http://www.google.com/search?h...Watts
54 293.75 ((pound force * inch) / sec) = <U>6134.37006 Watts</U>

Now, how much current do you need to drive a 6100 watt motor with a 12 volt battery? 510 Amps. Your battery won't last long. And anyway, you'd be happy if your pump was 75% efficient (approaching typical T3 Turbo efficiency), so you really need more power than that.



-Chris

TorganFM.

The real electric superchargers I have seen are $3k+ and have huge capacitors that store a ridiculous amount of energy, and can run for like 15 seconds at a time. To me it just doesn't seem worth it. $3k for a drag race only supercharger.

Chris F

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DanW &raquo;</TD></TR><TR><TD CLASS="quote">The real electric superchargers I have seen are $3k+ and have huge capacitors that store a ridiculous amount of energy, and can run for like 15 seconds at a time. To me it just doesn't seem worth it. $3k for a drag race only supercharger.</TD></TR></TABLE>

Yeah. A real electric motor on a real compressor will do the job, but f*** it, might as well put a belt on the thing and drive it from the motor.

This thing (below) is going to be mostly useless. 1 PSI, probably.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ebay_cheap_supercharger &raquo;</TD></TR><TR><TD CLASS="quote">DO NOT BE FOOLED BY the home depot style ventilation, centrifugal blowers now being offered on eBaY for $50. they are 2.7amps/12volts and will do nothing with their 35watts of power. ALSO, Do not be fooled by the "Build your own clone eRAM for under $60" these guys are selling plans that point you to parts that will not make a fan with anywhere near the pressure and flow of the eRAM. These instructions point you to websites of a 1lb thrust fan and 15amp motor. It will do nothing for your engine!! The eRAM is 700WATTS, thats 3+lbs of thrust, and 1psi of pressure/900cfm!! The motor and axial flow compressor fan alone would cost you over $275 if you bought the parts on your own!! (and thats without wiring,microswitch,connectors,adapter tubes, relays, assembly, testing and balancing etc!) Do the math, Save your money for a real axial flow electric supercharger, that works and works for the right reasons!! </TD></TR></TABLE>

TorganFM.

http://www.autospeed.com/cms/A_2063/article.html

ESC thingy. I got some of my figures wrong, but there is about the only worthwhile thing you will find.

JRciv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by classciv &raquo;</TD></TR><TR><TD CLASS="quote">

if you think about it, it makes sence, basically i was asking to see if anyone had tried them out to see what effect they did have, or if there was a cheeper supercharger setup that actually did anything at all. never hurts to ask questions, although i usually dont because for some reason people like to post things that have nothing to do with the question itself.</TD></TR></TABLE>


Hey don't get uppity - you're the one asking a question that has been answered a million times before.


First of all, the cheap superchargers only offer a few psi and have no fuel management or means of tuning. Not a good idea.

The good superchargers (Thomas Knight is all I know of) work fine, but have their pros and cons.

Pros:
-Up to 20psi
-No parasitic power loss because the belt isn't crank driven
-No lag - electric motors make max torque at zero rpm so boost is instant

Cons:
-18,000watt power consumption requires battery bank in the trunk which is heavy.
-Only good for short passes - the alternator takes a while to charge the battery bank back up.
-It's really more like nitrous than anything. Not for street cars.