How do the 'BAR' numbers (1-32) corespond to actual pressure?
 

Does anyone know?

I mean sure you can look at the scale down the bottom and approximate, but im wondering if anyone actually knows what BAR number relates to what InHG/KPa or PSI?

Thanks Evil Aviator, but I already know how to convert from KPa to PSI and whatnot.

What I am looking for is how the BAR numbers corespond to actual KPa values.

You can find 0, 25, 50, 75, 100 fairly easy... But what about the values in between?
Ie, there are 4 graduations between 0 and 25 and its hard to tell where the bar lines are.

100kPA = 1atm, I think - or it might be 1bar.
1atm = 14.7psi
1bar = 14.5psi
It's kinda close.
I just round up to 15psi just to make the calculations easier.
So half of that is 7 or 7.5psi.
On a 3bar "map", 1 "bar" is about 1-2psi...
The E11 should give you accurate kPA readings in the upper right hand corner when you're changing bars?


-Ted

Well I dont have an E11, its for an F9a.
But if you do have an E11 or if someone else does, it would really help me if you could tell me which bar represents which KPa value. Ie, bar 18 = <value>KPa

And yeah 100kpa = 1 bar = 14.5 Psi.

Still doesn't help my problem.. :)

bar - kPA
1 -100
2 -90.32
3 -80.65
4 -70.97
5 -61.29
6 -51.61
7 -41.94
8 -32.26
9 -22.58
10 -12.90
11 -3.23
12 6.45
13 16.13
14 25.81
15 35.48
16 45.16
17 54.84
18 64.52
19 74.19
20 83.87
21 93.55
22 103.23
23 112.90
24 122.58
25 132.26
26 141.94
27 151.61
28 161.29
29 170.97
30 180.65
31 190.32
32 200.00


-Ted

I see, you want to know the pressure values of the 32 "bars" on your F9.

Unfortunately, this is not a simple question. It depends on whether you are using TPS or MAP for load sensing. If using a MAP sensor, then it will also depend on which MAP sensor you have, and even then the value would be in absolute pressure, while I assume you are looking for boost or vacuum pressure.

The easiest way to correlate the F9 bars to boost or vacuum pressure is to buy a boost/vacuum gauge. Since ambient pressure and temperature changes will change this correlation, you will always need to reference the boost/vacuum gauge for an accurate value, or you will need to convert the absolute pressure to gauge pressure.

For just a general correlation, I guess you could assume a linear distribution of the MAP or TPS, and calculate values from there. It will not be accurate, but will give you a ball park figure. Example for 2BAR MAP:

Given:
2BAR MAP sensor in the F9 is -100kPa to 100kPa = 200kPa total range
and the F9 has 32 "bars" displayed, then...

200kPa / 32 = 6.25kPa per "bar", therefore...

F9 "bar" #16 = 0kPa, and each sequential "bar" before or after that is + or - 6kPa, depending on which direction you go.

Now, this is based on absolute pressure, so you would need to correct this value if your ambient weather conditions differ from 15degC and 1013.2 mb barometer. Or, you could just use a boost/vacuum gauge and be done with it. ;)

He is looking for the value of the load bands of the F9. Darn Haltech just had to call them "bars" to confuse everybody. At least Wolf uses "percent". ;)

Thanks guys I already drew up a graph from some known points to work out values but it just doesnt work too good I want it acurate.

RETed do you have another set of values like that but for a 2bar MAP sensor?

Well, the easy way to partly figure out what kind of pressure is in respect to the bars is like this, just divide the number of bars by PSI and you get a rough estimate, 3 bar map sensor you divide the first amount of bars by 30psi), if you have a 2 or a 1 bar then it works the same way, # of bars divided by PSI total.

Later,

He is just using the linear method like I described. Hmm, I just noticed I should have divided by 31 instead of 32. Oh well, I think you should still understand the main idea.

Here is a 2Bar list that I copied from an Excel spreadsheet that took me all of 3 min to produce. I would imagine that RETed did the same thing, but for a 3Bar sensor.

1 -100.00
2 -93.55
3 -87.10
4 -80.65
5 -74.19
6 -67.74
7 -61.29
8 -54.84
9 -48.39
10 -41.94
11 -35.48
12 -29.03
13 -22.58
14 -16.13
15 -9.68
16 -3.23
17 3.23
18 9.68
19 16.13
20 22.58
21 29.03
22 35.48
23 41.94
24 48.39
25 54.84
26 61.29
27 67.74
28 74.19
29 80.65
30 87.10
31 93.55
32 100.00

You will need to convert to gauge pressure to be more accurate.

bar - kPA
1 -100
2 -93.55
3 -87.10
4 -80.65
5 -74.19
6 -67.74
7 -61.29
8 -54.84
9 -48.39
10 -41.94
11 -35.48
12 -29.03
13 -22.58
14 -16.13
15 -9.68
16 -3.23
17 3.23
18 9.68
19 16.13
20 22.58
21 29.03
22 35.48
23 41.94
24 48.39
25 54.84
26 61.29
27 67.74
28 74.19
29 80.65
30 87.10
31 93.55
32 100

haha, Evil Aviator is good. :)

I actually paged through the E11 proggie and wrote down all the number.
BTW, http://www.haltech.com/ has downloads for these E11 programs.


-Ted

Doph, you did it the hard way! lol

This is a wrough calculation of the messurements.

^ Excellent :)

...So why are they different?....


How did you work yours out Claudio RX-7?

To be totally honest i guestimated it based on the number of total bars available and spread the range of the sensor according to them. Basically just dividing the scale by the number of bars. For example, if a 1 bar map sensor has a range of 0-29.4psi (101kpa) and you have 32 total bars, each bar will be at .918psi (3.156kpa), aproximately, from each other.

I have seen somewhere on the internet the scale vs. voltage of the 1 and 2 bar map sensors, but for the life of me i cant seem to find them anymore. Thats why i did the guestimate.
:D

The scale in the new Haltech windows software now shows more divitions in it, not just minium and max values, but they havent released a version of it with imperial units yet, its all still metric.