Ford MAP sensor 1S7A-9F479-AB (Bosch 0 261 230 044) baro calibration

[Hanns Per]

I am looking for the calibration figures for this sensor pls.  Had no success in the web.

thks in advance

Hanns Per

[aerobod - near CYYC]

Hanns Per, if this is the standard Ford combined IAT / MAP sensor as used by Caterham, here is the stock calibration with ambient pressure being referenced as 0 Bar:

0V -0.992 Bar

1.0V -0.749 Bar

2.0V -0.506 Bar

3.0V -0.263 Bar

4.0V -0.020 Bar

5.0V 0.223 Bar

 

 

[Hanns Per]

Thank with the SBD Baro , Volts in steps of 1/3 Volt and the Ford sensor I have also increases bar with increased volts?

0.0V 0.000 bar    0.071    0.141    0.212    0.283    0.353    0.424    0.495    0.565    0.636    0.707    0.777    0.848    0.919    0.989   5.0V  1.060 bar
 

[aerobod - near CYYC]

Hi Hanns Per, that is the same calibration I have for the standalone SBD baro sensor, but it is calibrated in Easimap relative to absolute pressure as opposed to the MAP sensor being calibrated relative to ambient pressure. The Ford MAP sensor used by Caterham seems to have a slightly different sensitivity, about 20% different from the SBD one, both are linear for voltage vs pressure, though.

[Hanns Per]

Hi James, I have the am. figures also for the my SBD baro sensor but since I will make me an airbox I will go back to the Ford combined MAP Sensor  which was on the Plenum when I got the car in 2005.  Today I had 0.97 bar with the SBD sensor, with this info I could  define the correct value for the Ford /Bosch sensor also showing 0.97 bar But I miss all the other points :-(

Hanns Per

[aerobod - near CYYC]

Looking back at my logs, I'm at an altitude of 1250m, but my Ford MAP sensor typically reads around -0.127 and the SBD baro sensor 0.870 when the engine is off. There may be a small calibration difference, but adding 1.0 Bar to the Ford values when used as a MAP to calibrate it as a baro sensor would be fairly accurate. This would give the pressure values for each of the 1/3 V increments:

(0V) 0.008 0.089 0.170 0.251 0.332 0.413 0.495 0.575 0.656 0.737 0.818 0.899 0.980 1.061 1.142 1.223 (5V)

If your SBD sensor baro calibration at 0.970 Bar pressure is measuring 4.60V, the Ford MAP sensor would be measuring 3.96V.

Bear in mind though that having the sensor inside the airbox could cause a slight inaccurate reading of baro pressure due to air flow characteristics that could change with engine RPM, as opposed to just changing with ambient pressure changes.

[Hanns Per]

Thats what I just found in a 2015 map qhwew I usws this sensor

0.000    0.083    0.165    0.248    0.331    0.413    0.496    0.579    0.661    0.744    0.827    0.909    0.992    1.075    1.157    1.240
 

[Hanns Per]

I had my SBD baro sensor under the scuttle which I think was wrong because I realized under the bonnet the pressure increases with speed. I will feed the airbox from the front which will lead to a higher pressure in the airbox. I could make a valve to release the higher pressure? 

[aerobod - near CYYC]

If you can get some ram effect into the air box, it is worth putting the baro sensor in there and adjusting for any inaccuracy in measuring ambient pressure by adjusting the fuel maps a small amount. My baro sensor is on top of the ECU and IAT sensor is near the engine mount closest to the air intake of my R400D, as I don't have an airbox, just the K&N cone filter attached to the throttle body on the plenum intake.

If you are not using a rolling road to fine tune the fuel maps and don't have a wideband Lambda sensor, it is worth changing the stock narrow band sensor to a wideband system. I played around with a custom cold air intake and found the air intake changes required about 0.02 Lambda compensation across the board and about double that in a couple of areas, especially in the 5,500RPM area.

I did all the adjustments after capturing about an hours worth of data in Easimap from road use across a varied range of revs and throttle positions. Basically I took the logged files and output in 50ms intervals to CSV format and then input into a spreadsheet (LibreOffice in my case) and created a pivot table of averaged Lambda values for a matrix of RPM (in 500RPM increments) vs throttle site (rounded to the nearest integer). This pivot table was then used to nudge the fuel injector opening times appropriately to achieve the desired Lambda values. After adjustment another logging session and output pivot table confirmed the adjusted values were then correct.

[Hanns Per]

very impressive I have my map from a rolling road but thank You very much for writing me You approach worthwhile crosschecking. Where do You see the advantage of having 2 air pressure sensors in "ambient" environment?

[aerobod - near CYYC]

I don't use the MAP sensor anymore for mixture adjustment, just for data logging of the plenum pressure. With the external baro sensor I can deal with ambient pressure changes over the 2,000m vertical I can encounter in the mountains, but I changed to AlphaN mapping with altitude compensation from the default Caterham MAP mapping which doesn't compensate for altitude changes (defaulting to 1.040 Bar ambient).

On my car I have the baro sensor input on pin 28 of the ECU and MAP sensor on the default pin 21.