Bottoz' Atom Mods, Step #1

[rfmarz@frontiernet]

McFred brings up an interesting point. If there is any kind of skirting in the front, the pressure under the car is lower. I wonder where the pressure is actually lower. THAT would be the correct direction for the air to flow towards.

[McFred]

[quote="forcesevens"]
I hear the bottom of cars have higher pressure.[/quote]

Higher than what?  It's lower than ambient when the car is moving through the air.  When fluid has to speed up to go around something (because it's incompressible) its pressure drops (conservation of energy, aka Bernoulli's principal).  This is what causes helmet lift, the need for airports, etc.  So when air has to speed up to get around a car body, its pressure drops on all sides of the car and the pressure drop is often biased to generate downforce by designing the shape of the underside of the car, front lip, etc. to produce a lower pressure below the car than above.  You do not necessarily need a "wing" to get downforce.  Anyway, whether or not the pressure "under" the front section of an atom is higher or lower than just behind the front radiator is not an easy armchair calculation imo.  The pressure behind the radiator is certainly lower than in front, but how the limited body paneling at that section factors in would be difficult to say.  I'd guess that it doesn't really matter much which way the fan points, but it's easy enough to just go out and observe the natural direction of flow and point the fan the same way.  If there's too much turbulence to use the string/ribbon method, you could maybe see if the fan will windmill and use that to see which direction the flow prefers.  Another thing to consider, is whether running the fan the "right" way means running it opposite to the rotation direction the fan blades were designed for.  That might hurt the fan efficiency more than you'd gain from going with the natural flow.  Just thinking out loud, but I guess the answer for now is water injection 

http://en.wikipedia.org/wiki/Bernoulli%27s_principle

[rfmarz@frontiernet]

Along those lines, if we had a small air dam in front of the air intake, it would create a vacuum and help the fan blowing down.

[Kempo]

Regardless of pressure it is not  a good idea to use the fan to push the air down instead of pulling air up from the bottom of the car. If you use the fan to push the air down you would be heating the H/E radiator instead of cooling it. The air you would be pushing down has just gone trough the engine coolant radiator and will be hotter that the ambient temperature so it will be like trying to cool it with a hair dryer blower.

[rfmarz@frontiernet]

I don't quite understand.

[Kempo]

I don't know what that terminal on the fuse box is for(don't have the car with me at the moment). But it looks to me you have connected it to a battery direct power source on the fuse box. That is why it turns on even if the ignition switch is off. You need to connect it to a circuit that is controlled by the ignition switch.



Hope this helps,

Hugo

[bolus]

there is a jumper on the back that needs to be removed I believe, otherwise it draws power from the OBD port.  It should be in the directions

This may help:
http://cobaltss.net/forums/showthread.p ... nterceptor
http://www.cobaltss.net/forums/showthre ... nterceptor

[Wmcmanus]

[quote="Spanky"]
I am electronicly impaired. [/quote]

I believe the term is 'mechanically declined'.  Me too!