More silly ideas-MAP2

[Greg Hermann]

>About the A/C pressurizing the interior of the car...
>
>I asked my Dad how many pounds of pressure he thought the A/C
>pressurized his Riviera when we were cruisin around a while back... Like
>when I was 8 yrs old or so!!  I'm now 30... Haven't EVER heard of anyone
>else ever mentioning this or anything until NOW!
>
>He said it may pressurize the cabin by up to about 5 lbs. or so!  Anyone
>have a different guess?

Nahhh--the fan in the AC unit is lucky if it makes 1 or 1.5  INCHES, WATER
COLUMN of pressure inside the car, even when it is on high (and you do not
have the control on recirc.

More pressure involved from the "stagnation" pressure of the air going into
the vent if you are going down the highway fast and the intake is in a high
pressure location--like at the bottom of the windshield.

The stagnation pressure of air at 70 mph (at sea level) is about 2.4" of
water column, to give you an idea.

While on this one--if you are going to put a constant barometric reference
into an ecu, it makes sense to take total pressure at the inlet to the air
cleaner, so that any "ram-air" effect due to vehicle speed is compensated
for! Course--a serious controls-programmer sort could use a more neutral
barometric pick-up point, and compensate for vehicle speed ram-air effects
using the VSS input to the ecu!

Greg