Berman's 7.3 build

lincolnlocker · Apr 27, 2014

dsberman94 said:
Holds at 25 while bp is in the 40s

Posted from ***itville, USA

How are you measuring bp?

dsberman94 · Apr 27, 2014

lincolnlocker said:
How are you measuring bp?

Insight

Posted from ***itville, USA

TyCorr · Apr 27, 2014

Yea bp is one of the available pid's on the cts. I use it too. It's absolute (think that's the term) reading though. Whereas boost is gauge pressure (ambient atmospheric pressure isn't measured) . You have to subtract atmospheric pressure from the bp reading for it to make sense.

TyCorr · Apr 27, 2014

If your bp sensor is ****ed the cts will show 18 psi all the time.

dsberman94 · Apr 27, 2014

TyCorr said:
If your bp sensor is ****ed the cts will show 18 psi all the time.

It definitely doesn't do this. I'll mess with is tomorrow and watch pb along with boost and I'll mess with the wastegate when I get home tomorrow. How do I know atmospheric pressure? Thanks for you help Ty and jake.

TyCorr · Apr 27, 2014

Atmospheric pressure is a constant unless you live at altitude. That's what effects guys up high.

Just as if you dug a hole 5k feet deep you'd have close to 30 psi of atmospheric pressure plus whatever forced induction.

dsberman94 · Apr 27, 2014

TyCorr said:
Atmospheric pressure is a constant unless you live at altitude. That's what effects guys up high.

Just as if you dug a hole 5k feet deep you'd have close to 30 psi of atmospheric pressure plus whatever forced induction.

So atmospheric pressure is right about 14.2 give or take a couple decimals for the slight elevation.

TyCorr · Apr 27, 2014

dsberman94 · Apr 27, 2014

TyCorr said:
No.

Ok so it's 14.2.

TyCorr · Apr 27, 2014

No its 14.7 at sea level. My phone keeps changing it to 14.2. I turned swipe off and corrected myself. It's literally the weight of the atmosphere.

I don't have the foggiest idea what it's like at 5k feet or 10k feet. No clue.

swinky · Apr 27, 2014

14.7 I thought

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dsberman94 · Apr 27, 2014

TyCorr said:
No its 14.7 at sea level. My phone keeps changing it to 14.2. I turned swipe off and corrected myself. It's literally the weight of the atmosphere.

I don't have the foggiest idea what it's like at 5k feet or 10k feet. No clue.

I'm too tired to figure out the math now so maybe tomorrow I'll get a few minutes. I sometimes enjoy doing stupid math like that. I'm curious as to what it is at my slight altitude and at higher elevations like bandimere and at low points like Death Valley. Ill do math and research tomorrow because I'm curious.

backwoodsboy · Apr 28, 2014

The fundamental equation is:
P = Po + dgh
Po = atmospheric pressure at sea level (101 kPa)
d = density of air
g = gravity (9.8m/s^2)
h = vertical distance in meters

This is skewed, as air is a compressible fluid. As such, density is not constant. You can use integrals though.

They more direct approach is:

p = 101325 (1 - 2.25577*10^-5)5.25588
where

p = air pressure (Pascal (Pa))

h = altitude above sea level (m)

1 Pa = 0.000145037738 pounds per square inch

Or you can do what engineers do and look at a table:

http://www.sablesys.com/baro-altitude.html

swinky · Apr 28, 2014

backwoodsboy said:
The fundamental equation is:
P = Po + dgh
Po = atmospheric pressure at sea level (101 kPa)
d = density of air
g = gravity (9.8m/s^2)
h = vertical distance in meters

This is skewed, as air is a compressible fluid. As such, density is not constant. You can use integrals though.

They more direct approach is:

p = 101325 (1 - 2.25577*10^-5)5.25588
where

p = air pressure (Pascal (Pa))

h = altitude above sea level (m)

1 Pa = 0.000145037738 pounds per square inch

Or you can do what engineers do and look at a table:

http://www.sablesys.com/baro-altitude.html