2 bar SD tune
05-13-2009, 02:58 PM
#1
2 bar SD tune My car has a 2 Bar SD tune on it right now and was tuned on only 10 lbs of boost. How high will a 2 BAR tune read boost to? Is it 15 lbs? If my car was tuned on 10 lbs of boost is it safe to up it to 15 lbs without adjusting the tune? I would be adding higher octane fuel to do so.
05-13-2009, 03:29 PM
#2
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The 2 Bar sensor is good to 15PSI. Whether your tune is good to 15PSI is unknown. Did your tuner make a reasonable VE table above the 10PSI mark? The only way to know for sure is to log it with a Wide Band O2 sensor.
Jeff
Jeff
05-13-2009, 07:06 PM
#5
First, there is a lot of fudging and rounding off going on.
Second, there are actually 3 standards for pressure being used:
Bars, or barometric pressure (at sea level during calm conditions = 1 Bar).
PSI, or pounds per square inch. 1 bar is considered to be 14.5 psi., which is what you are referring to.
kPa, or kiloPascals, which is what the manufacturers actually rate their MAP sensors at.
The conversion is this:
100 kPa = 1 Bar
Finally, you need to go to the place you are getting the sensor from, and examine their published data.
For example, I went over to lsxtune and collected the data they publish:
1 Bar - 15 to 102 kPa
2 Bar - 0 to 220 kPa
3 Bar - 40 to 304 kPa
So, to be completely accurate, you should collect the data and convert. Or you can use generalities and get close enough.
Finally, you can use the Bar to Psi conversion to get the accepted correct values:
1 Bar = 14.5 psi
2 Bar = 29.0 psi
3 Bar = 43.5 psi (LT1 fuel pressure)
4 Bar = 58.0 psi (LS1 fuel pressure)
Second, there are actually 3 standards for pressure being used:
Bars, or barometric pressure (at sea level during calm conditions = 1 Bar).
PSI, or pounds per square inch. 1 bar is considered to be 14.5 psi., which is what you are referring to.
kPa, or kiloPascals, which is what the manufacturers actually rate their MAP sensors at.
The conversion is this:
100 kPa = 1 Bar
Finally, you need to go to the place you are getting the sensor from, and examine their published data.
For example, I went over to lsxtune and collected the data they publish:
1 Bar - 15 to 102 kPa
2 Bar - 0 to 220 kPa
3 Bar - 40 to 304 kPa
So, to be completely accurate, you should collect the data and convert. Or you can use generalities and get close enough.
Finally, you can use the Bar to Psi conversion to get the accepted correct values:
1 Bar = 14.5 psi
2 Bar = 29.0 psi
3 Bar = 43.5 psi (LT1 fuel pressure)
4 Bar = 58.0 psi (LS1 fuel pressure)
05-13-2009, 10:22 PM
#6
I like using a calculator like this
http://www.dragsource.com/index.php?...s&calctoview=8
You have to subtract atmospheric pressure (14.5= 1 bar) though, as stated above.
http://www.dragsource.com/index.php?...s&calctoview=8
You have to subtract atmospheric pressure (14.5= 1 bar) though, as stated above.
05-14-2009, 07:38 AM
#7
First, there is a lot of fudging and rounding off going on.
Second, there are actually 3 standards for pressure being used:
Bars, or barometric pressure (at sea level during calm conditions = 1 Bar).
PSI, or pounds per square inch. 1 bar is considered to be 14.5 psi., which is what you are referring to.
kPa, or kiloPascals, which is what the manufacturers actually rate their MAP sensors at.
The conversion is this:
100 kPa = 1 Bar
Finally, you need to go to the place you are getting the sensor from, and examine their published data.
For example, I went over to lsxtune and collected the data they publish:
1 Bar - 15 to 102 kPa
2 Bar - 0 to 220 kPa
3 Bar - 40 to 304 kPa
So, to be completely accurate, you should collect the data and convert. Or you can use generalities and get close enough.
Finally, you can use the Bar to Psi conversion to get the accepted correct values:
1 Bar = 14.5 psi
2 Bar = 29.0 psi
3 Bar = 43.5 psi (LT1 fuel pressure)
4 Bar = 58.0 psi (LS1 fuel pressure)
Second, there are actually 3 standards for pressure being used:
Bars, or barometric pressure (at sea level during calm conditions = 1 Bar).
PSI, or pounds per square inch. 1 bar is considered to be 14.5 psi., which is what you are referring to.
kPa, or kiloPascals, which is what the manufacturers actually rate their MAP sensors at.
The conversion is this:
100 kPa = 1 Bar
Finally, you need to go to the place you are getting the sensor from, and examine their published data.
For example, I went over to lsxtune and collected the data they publish:
1 Bar - 15 to 102 kPa
2 Bar - 0 to 220 kPa
3 Bar - 40 to 304 kPa
So, to be completely accurate, you should collect the data and convert. Or you can use generalities and get close enough.
Finally, you can use the Bar to Psi conversion to get the accepted correct values:
1 Bar = 14.5 psi
2 Bar = 29.0 psi
3 Bar = 43.5 psi (LT1 fuel pressure)
4 Bar = 58.0 psi (LS1 fuel pressure)
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05-14-2009, 09:34 AM
#8
It is my understanding that the 1 bar can only read vacuum pressure to 1 bar(14.5psi) which is actually 0psi of boost because that is the atmospheric pressure of earth, the 2 bar will read up to 14.5psi of boost above atmosphere and the 3 bar up to 30psi.
05-14-2009, 09:46 AM
#11
Atmospheric pressure is 14.7XX - 14.9 PSI (depending on which standard you use), meaning 1 Bar, or a stock MAP sensor, those values listed don't look to be 100% accurate.
No, you need a 3 Bar if you want to be able to control at 18psi, the values he listed for each level include atmospheric pressure which is not generally considered boost. A 2 Bar MAP sensor is only good to control upto 14.7psi of boost. You need either a 2.5 Bar or 3 Bar to control anything above that.
No, you need a 3 Bar if you want to be able to control at 18psi, the values he listed for each level include atmospheric pressure which is not generally considered boost. A 2 Bar MAP sensor is only good to control upto 14.7psi of boost. You need either a 2.5 Bar or 3 Bar to control anything above that.
05-14-2009, 12:41 PM
#12
well, technically speaking, koolaid is correct. 1 bar is 100kpa. However, 1 bar is not necessarily standard atmospheric pressure, it is more like 101.3kPa or roughly 14.7psia. Regardless tho, koolaid was right again- you need to get the specs from the manufacturer of the sensor to be dead on.
And on the other subject, there are 2 different kinds of pressure ratings. psia, and psig. psia is absolute pressure, which is measured from a complete vacuume with 0 pressure. On earth, at sea level, the average pressure is 14.7psi- just slightly over 1 bar. however, we are so used to this, and so accustomed to it that we often just refer to pressure as anything OVER our standard atmosphere. so when people say a psi rating, in general, they are referring to psig. That is the pressure a gauge would measure over standard atmospheric pressure.. So in summary, 14.5psia=0psig=1bar=100kPa... Clear as mud now?
And on the other subject, there are 2 different kinds of pressure ratings. psia, and psig. psia is absolute pressure, which is measured from a complete vacuume with 0 pressure. On earth, at sea level, the average pressure is 14.7psi- just slightly over 1 bar. however, we are so used to this, and so accustomed to it that we often just refer to pressure as anything OVER our standard atmosphere. so when people say a psi rating, in general, they are referring to psig. That is the pressure a gauge would measure over standard atmospheric pressure.. So in summary, 14.5psia=0psig=1bar=100kPa... Clear as mud now?
05-14-2009, 01:49 PM
#13
And to continue the thread of thought (and add to the confusion) consider the 2 bar MAP sensor I got the specs for (and those are real specs, I did not make them up). Go here http://www.lsxtune.com/shop/index.php/cPath/129_143 to view them. They have multiple 1,2 & 3 bar sensors listed. I picked one of each at random.
220 kPa = 2.2 Bar. That is the top of the range the MAP sensor will yield accurate readings (they also list the voltage it outputs, which is what the PCM reads, but I did not want to make it even more confusing.
At 1 Bar = 14.5 psi, 2.2 Bar = 31.9 psi. You could take the shortcut, subtract atmospheric pressure, call it 1.2 Bar of boost, which is 17.4 psi of boost.
If you use 1 Bar = 14.7 psi, that yields ~17.7 psi of boost.
So, in theory, that particular MAP sensor will be accurate for up to 17.4-17.7 psi of boost.
I tend to use 14.5 psi b/c I am an engineer and we tend to approach everything in absolute values. For example, we tend to discuss things in units of mass instead of weight, since things will weigh differently on the moon. No, really.
220 kPa = 2.2 Bar. That is the top of the range the MAP sensor will yield accurate readings (they also list the voltage it outputs, which is what the PCM reads, but I did not want to make it even more confusing.
At 1 Bar = 14.5 psi, 2.2 Bar = 31.9 psi. You could take the shortcut, subtract atmospheric pressure, call it 1.2 Bar of boost, which is 17.4 psi of boost.
If you use 1 Bar = 14.7 psi, that yields ~17.7 psi of boost.
So, in theory, that particular MAP sensor will be accurate for up to 17.4-17.7 psi of boost.
I tend to use 14.5 psi b/c I am an engineer and we tend to approach everything in absolute values. For example, we tend to discuss things in units of mass instead of weight, since things will weigh differently on the moon. No, really.
05-14-2009, 03:46 PM
#15
05-14-2009, 05:34 PM
#17
a MAP sensor is not brain surgery, its a simple calibrated resistor pretty much.. All it does is take a constant 5V input and a ground, and then it outputs a signal 0-5V based on what it is measuring. So a 2 bar MAP sensor when it is sensing 2 bar of pressure will read 5V on the output signal, and 2.5V at 1 bar, and 0V at 0 bar. A 1 bar MAP sensor will read 5V at 1 bar, 2.5V at 1/2 bar, and 0V at 0 bar. And a 3 bar.. yep- you guessed it: 5V at 3 bar, 2.5V at 1.5 bar, and 0V at 0 bar...
05-14-2009, 06:19 PM
#18
You will want the 3 Bar sensor. Just understand that you will lose accuracy. Sorry to make it so difficult, but the range you want to be at is right at the edge of a 2 Bar and a 3 Bar. You cannot emphatically say "A 2 Bar sensor will only go to 15 pounds of boost" because they vary.
If you knew the actual numbers from the MAP sensor you currently have, you could tell how high it will go before being maxed out. You might try to find its part number and Goggling it.
If you knew the actual numbers from the MAP sensor you currently have, you could tell how high it will go before being maxed out. You might try to find its part number and Goggling it.
05-14-2009, 06:20 PM
#19
a MAP sensor is not brain surgery, its a simple calibrated resistor pretty much.. All it does is take a constant 5V input and a ground, and then it outputs a signal 0-5V based on what it is measuring. So a 2 bar MAP sensor when it is sensing 2 bar of pressure will read 5V on the output signal, and 2.5V at 1 bar, and 0V at 0 bar. A 1 bar MAP sensor will read 5V at 1 bar, 2.5V at 1/2 bar, and 0V at 0 bar. And a 3 bar.. yep- you guessed it: 5V at 3 bar, 2.5V at 1.5 bar, and 0V at 0 bar...
