One BAR equals 14.7 psi at every point of altitude?
 

Hello people. I have a quick question. I live on El Paso, it around 3 to 4k feet in altitude. My boost gauge reads the regular boost pattern in every gear except 5th. I can hit 1 bar when I go WOT on 5th. I am worried since our cars on stock form cannot handle 14.7 psi. However, I was told that 1 bar is not equal to 14.7 psi where we live. I was told that it is closer to 12.2 or so. That it varies with altitude, is this true? Thanks for the help. Cheers

Ok, this part I am positive of: i bar = 14.5 psi. 14.7 is the stoichiometric a/f ratio. In 5th gear you are likely to see more boost than the other gears b/c of more load on the turbos.

This part, not so sure: 1 bar is 1 bar, no matter where you are :). For example, the air is thinner in colorado.....your turbos would have to work harder to push the same amount of boost as a person at sea level.

Someone else chime in :)

From http://www.scuderiaciriani.com

"Many owners still get boost conversions wrong because they confuse the different standards, or don't know what unit of measurement their boost gauge uses. It should be stated on the dial face.

My HKS boost gauge reads in Kg/Cm^2. The following is rounded to one decimal point.

One ATM is equal to 14.7 PSI.

One Kg/Cm^2 is equal to 14.2 PSI.

One BAR is equal to 14.5 PSI.

(ATM = atmosphere, the normal pressure at sea level of earth's atmosphere) "

For anyone that actually cares (and since I'm bored), I have some additional precision:

1 bar = 14.503774 psi
1 atm = 14.695949 psi

what the hell..... i thought that "bar" was atm, same with kg^2 or whatever.... why do they have like 15 different things.... why not just use atm?

so gay....

1 bar on the gauge means the pressure in the manifold is 14.5 psi above ambient, regardless of elevation. But at 3500 ft, ambient air pressure is 13 psi, vs 14.7 at sea level.

Mass (amount) of air in the manifold is based on ambient + boost pressure. So at one bar boost in el paso, power will be down by 1.7/29.2, or about 6 %, vs sea level.

OEM ecu fuel cut limits for boost are listed in absolute pressure, boost + ambient. So at high elevations, you can run higher boost without fuel cut, vs sea level.

Had a quick question regarding elevation...

I was wondering how would AFR's be effected if boost was not adjusted at high elevation? I'm assuming it would get richer...am I correct? Thanks guys.

at the same manifold air temps it would be the same, if humidity is the same. not going to happen as at 5,000 feet the turbos will have to work harder to compress the thin air to x.x psi.