12v DC Blower - Fuel Economy, Hypermiling, EcoModding News and Forum

BHarvey · 07-01-2012, 02:40 PM

Been thinking about rigging 1 or 2 blowers powered by a 12v car battery in the trunk, to fill in some of the air at the back of the car, mainly on uphill sections or anytime a good load is present.

Reading about the Coanda slots started my thinking about this and the choices are down to either a 12v car battery set up, or a big scuba tank at 3k+ psi.

I remember reading that at a rate of .2 psi would net 10%+ better mpg, BUT, as we all know low pressure equal massive flow and I fear the scuba tank would run out before the gas tank(which usually lasts me 18-20 hours).

My thoughts are two holes, one on either side of the license plate for the blower/s to feed air into the void behind the car. Found many different types that range in amp requirements and CFM.

Otherwise, twin .5 amp, 32 cfm blowers would yield 64 cfm at 1 amp on a 500 amp/hour battery should easily last any trip I might encounter.

What do you think would be needed to see a gain?

Frank Lee · 07-01-2012, 02:55 PM

I think it'll take more than two holes unless they're HUUUUGE

Ryland · 07-01-2012, 09:53 PM

at 64cfm, it would help a great deal... if you were driving a pine wood derby car... really, with a frontal area of 1.5 square inches 64cfm would push a pine wood derby car along at about 65mph if there wasn't any friction on the skin, so it would make about as much difference as cutting 1.5 square inches off one of your mud flaps.

2000mc · 07-01-2012, 10:10 PM

how about the exact opposite? holes in the back to help draw air through the vents so you don't need to use your hvac blower. put a slide over a hole and make a variable sized hole instead of variable fan speed.

ksa8907 · 07-01-2012, 10:11 PM

I've considered something similar, running large diameter hose to the rear of the car with the front of the hose pulling air from a high pressure zone.

2000mc · 07-01-2012, 11:36 PM

Quote:

Originally Posted by ksa8907

I've considered something similar, running large diameter hose to the rear of the car with the front of the hose pulling air from a high pressure zone.

http://ecomodder.com/forum/showthrea...fits-9667.html

Ryland · 07-02-2012, 01:13 AM

Why not cut out the passenger side of the car to get ride of that high pressure zone?

oil pan 4 · 07-02-2012, 03:20 AM

Quote:

Originally Posted by ksa8907

I've considered something similar, running large diameter hose to the rear of the car with the front of the hose pulling air from a high pressure zone.

This was found of cars and trucks up until about the 1970s.
The old F100s had a foot operated vent on the passanger side.

Using blowers to change aero reminds me of blown flaps used back in the 1960s, they fell out of favor because of the added complexity and tremendous amount of power required to move enough air to change wing aerodynamics.