http://cgi.ebay.com/ebaymotors/ws/eB...category=46098

What a bargain!!! 250 cfm of Compressed Air Moving Power!!!!

 

Looks like someone fitted a filter onto a hair dryer.

 

Ha,hahahaha what a joke. I bet they sell the crap out of those to all the ricers.

 

my carb flows more than 250cfm

is that a hair dryer?

 

I saw that on eBay a couple days ago and just started LMFAO!

 

yeah, a turbo of about the same size needs to spin at 100,000 rpm or more to pump enough air. i'm sure that some cheap plastic fans can't spin that fast.

let's do a little math:

3.0 L engine at 3,000 rpm = 9,000 L/min of air

9,000 L/min = 9,000,000 cc/min = 550,000 cin/min = 320 cfm
and that's only at 3,000 rpm. it's twice that at redline.

let's say you wanted 2 pounds of boost. that's an increase from 15psi to 17psi,or 13%

so to add 2 pounds of boost you'd need somewhere near 360-370 cfm

i can't believe that these people can get away with selling such crap.

what i'd love to do is actually run a roots blower from a supercharger by a switched electric motor. that way you can have boost when you want it and no drag when you don't. you'd probably have to run a beefier alternator to be able to run enough current to a motor to pump enough air, but at least when you have the motor off, there'd be negligable drag.

 

Your math is off a by a factor of two right there. Considering that a 3.0 Toyota engine is a four-stroke engine, it takes two revolutions to draw 3.0 liters of air. So your first line should be:

3.0 L engine at 3,000 rpm = 4,500 L/min of air

 

Huh??? If the roots type blower is still in the airflow, it will heavily restrict airflow through it if it's not turning. Roots type rotors are designed to have very tight tolerances to their housing, if they aren't turning very little air can get by. Now I have seen something like this done using two superchargers. Visualize a 454 Chev with two small B&M superchargers mounted side-by-side on a custom pent-roof intake manifold. Each supercharger has a pair of small 4-barrel carbs. One supercharger is belt driven from the crank and runs all the time. The other is driven using an air conditioning style magnetic clutch and can be turned on when wanted.

 

If you want to get really technical, it's off by more that that, as no normally aspirated engien that I know of is capable of 100% volumetric efficiency. It would be reduced by another 20-35%.

 

Very true. At idle, a N/A engine "might" see 90% and it goes downhill from there to as low as 60% at redline. Usually VE reaches "best case" right about the torque peak of the power curve. After that, it drops off and so does torque/power.

 

Decided that the supercharger looked like quite a bargin, so I shelled out the bucks and went ahead with the install. It was pretty cool, LOTS more power, inclused a "master intall kit" for FREE.....and even threw in a FREE BLOCK HEATER!!!

Check the pics after install.

http://img67.exs.cx/img67/7896/supercharger.jpg

Here's the block heater before it went in...

http://img86.exs.cx/img86/6033/blockheater.jpg


Now I need one of those big Honda Civic wings to keep the rear tires on the ground at speed.

 

Pays to read the fine print before bidding eh?

 

Thats a good one! Haa, I bet my neighbors kid with the loud Honda already has one. I walked over there one day just to say hi and take a look under his hood, what a joke! blue vacuum lines, a Tornado intake thing, fake K&N filter setup, a $7 ebay strut brace that looked like a peice of all thread, the car has cut stock springs, and a very loud muffler big 18" cheap wheels, red calipers the words Limited on the doors and the list goes on! The bad thing is it was a really nice car when he bought it, a 99 Accord V6! Bling Bling yo, its a race car now... I love smoking him through the twisties in my Miata hell my 88 3.0 could beat him on these back roads