408 on the dyno friday

[pl4yboy]

According to the guys on HPT, the stock OS is good to 3bar with proper scaling.

[cjriojas]

What exactly do you mean by n-bar, n being an integer?

[pl4yboy]

What exactly do you mean by n-bar, n being an integer?

The ability for the OS to see N bars of psi and interperate it.

1 bar = 14.5037738 psi

2bar = 29 psi

1bar is good to around 10-12 psi of boost. It's good to leave a little left on the table. Most people go in increments of 10 in the boost world.

By bar, we are referring to the MAP sensor really. There are MAP sensors that read up to 3bars available for the GM OS.

[farmtruc]

Just not to confuse the guy asking the question.

2 bar is 14psi
3 bar is 29 (28)psi when speaking turbochargers/gauges/tire pressure, etc., zero referenced to atmosphere.

You're speaking of absolute pressure.


Don't forget, we live in a world that has an atmosphere, or at least some of us do

[pl4yboy]

Just not to confuse the guy asking the question.

2 bar is 14psi
3 bar is 29 (28)psi when speaking turbochargers/gauges/tire pressure, etc., zero referenced to atmosphere.

You're speaking of absolute pressure.


Don't forget, we live in a world that has an atmosphere, or at least some of us do

Sorry, I forgot. I'm used to the calculations I've done in Chem and Physics lately where it is asumed we are at 1 atm.

[George C]

was always under impressiong that 1 bar = 14.6, 2 bar was 29.2 which is 14.6 psi of boost, 3 bar is 43.5 [which is what most injectors are rated at] which is also 29 psi of boost

[Frenchy]

1 bar is atmospheric pressure at sea level. A column of air from sea level to the top of the atmosphere with a 1"x1" face weighs 14.6 pounds (this doesn't account for garbage in the air obviously). God damn I remembered something from school. So a 2 bar sensor reads 14.6 psi above atmospheric.

[cjriojas]

i didnt realize bar was referring to pressure, i thought it was something completely different

[farmtruc]

was always under impressiong that 1 bar = 14.6, 2 bar was 29.2 which is 14.6 psi of boost, 3 bar is 43.5 [which is what most injectors are rated at] which is also 29 psi of boost

You're trying to identify 1bar, which you did correctly, however, when speaking in terms of boost/tire pressure/fuel pressure, it's assumed you're referencing atmosphere at zero, not absolute pressure, which is atmosphere added into the equation.

1bar is what your stock engine is running at now, no pressure reading, 105kpa
2bar is 14psi - 210kpa VE table in hptuners, map sensor reads 14psi of boost (atmosphere + 1bar)
3bar is 29psi - 315kpa VE table in hptuners, map sensor reads 28psi of boost (atmosphere + 2bar)
etc...

I know, you know, what you're talking about when speaking boost/pressure/map sensor/bar, etc, just keeping it clear for those who are asking, because 2bar in relation to auto talk and fuel pressure isn't 29 (28) psi, it's 14psi.

I guess it just depends on how you're used to seeing it and calculating pressure, but almost everyone starts at zero, but when talking boost, assumes absolute pressure.

What a confusing thread.

I hope I didn't make any mistakes in this long post, hahaha.

[pl4yboy]

You're trying to identify 1bar, which you did correctly, however, when speaking in terms of boost/tire pressure/fuel pressure, it's assumed you're referencing atmosphere at zero, not absolute pressure, which is atmosphere added into the equation.

1bar is what your stock engine is running at now, no pressure reading, 105kpa
2bar is 14psi - 210kpa VE table in hptuners, map sensor reads 14psi of boost (atmosphere + 1bar)
3bar is 29psi - 315kpa VE table in hptuners, map sensor reads 28psi of boost (atmosphere + 2bar)
etc...

I know, you know, what you're talking about when speaking boost/pressure/map sensor/bar, etc, just keeping it clear for those who are asking, because 2bar in relation to auto talk and fuel pressure isn't 29 (28) psi, it's 14psi.

I guess it just depends on how you're used to seeing it and calculating pressure, but almost everyone starts at zero, but when talking boost, assumes absolute pressure.

What a confusing thread.

I hope I didn't make any mistakes in this long post, hahaha.

No its understandable. I was just confusing my regular daily calculations (including fuel and tire pressure). I wasn't aware that boost was referenced differently.