MAP support in non-CSL software

[mooninite]

Does the US DME software support a MAP sensor?

I'm rolling around the idea of a CSL airbox... would rather not load the CSL DME software since I already have my tune loaded I made myself.

I haven't seen anyone else question this so I wanted to put it out there. Thanks!

[Martyn]

Nope, MAP sensor requires CSL software.

[mooninite]

Certainly the logic is present... but just disabled in the data section. Was it discovered the MAP sensor logic doesn't exist in non-CSL firmware?

[Tomba]

Certainly the logic is present... but just disabled in the data section. Was it discovered the MAP sensor logic doesn't exist in non-CSL firmware?

The MAP sensor on the CSL was connected to the same input as the MAF sensor on a regular ECU. There is no software switch known the change to MAF or speed density. Only complete program and data changes.

If you still want the stock software you could consider to run alpha-n. This mode is actually quite good on these ECUs. From what I was told by a person that has disassembled the CSL software the MAP input does only little modification to the injection and ignition. Full load is ambient pressure and I would assume it runs on the alpha-n models. BMW probably used the MAP input to make sure it would pass the emission test by then.
Nearly all race engines I have seen use alpha-n models with non CSL software.

[MpowerE36]

Tomba is right. Here a post about it :

https://nam3forum.com/forums/forum/s...8452#post98452

[terra]

Certainly the logic is present... but just disabled in the data section. Was it discovered the MAP sensor logic doesn't exist in non-CSL firmware?

Logic is not present at all.

[mooninite]

Thanks for all of the replies. Great info.

[ac427]

The MAP sensor on the CSL was connected to the same input as the MAF sensor on a regular ECU. There is no software switch known the change to MAF or speed density. Only complete program and data changes.

If you still want the stock software you could consider to run alpha-n. This mode is actually quite good on these ECUs. From what I was told by a person that has disassembled the CSL software the MAP input does only little modification to the injection and ignition. Full load is ambient pressure and I would assume it runs on the alpha-n models. BMW probably used the MAP input to make sure it would pass the emission test by then.
Nearly all race engines I have seen use alpha-n models with non CSL software.

The MAP sensor output goes to a different pin on the ECU though.

Olza also mentioned that the MAP sensor was a backup device to the ECU on-board barometric sensor which all MSS54's have. This depressed me after spending all that money on genuine CSL parts.

[MpowerE36]

When the engine is not running, CSL software makes a comparaison between the pressure of the ECU on-board barometric sensor and the pressure of the MAP sensor. It allows to check if the MAP sensor works properly. Indeed, in these conditions, these two devices should approximately give the same pressure.

In normal conditions and when the coolant temperature is higher than 80°C, the RF calculated from the MAP sensor is used to do limited corrections (+/-2.5% maximum) of the RF calculated from the TPS (Alpha/N map 20x24). Most of people think that the CSL engine management system is a true speed-density but it is not. It is just a very fine Alpha/N engine management system.

Max value : 0xE5F0 (16bit ; signed ; formula=X/640 ; unit : rf(%))
Min value : 0xE5EE (16bit ; signed ; formula=X/640 ; unit : rf(%))

[ac427]

On old M3F i created a thread about the role of the MAP sensor after i heard from a top tuner that it was only used as a secondary device.

It was fitted because there had to be a secondary pressure sensor in case of failure and there was no MAF big enough for the CSL intake diameter.

I was a little bit worried by this and couldn't see why a device mounted nearer the cylinder head wouldn't be used as the primary pressure sensor instead of the ECU sensor.

olza actually disassembled the whole MAP routine to prove the point.

[MpowerE36]

MAP sensor is used in normal condition but with a very limited impact on the RF as I said before.

Yes, RF from MAP sensor is also used in case of failure (throttle position for example).

I also disassembled the whole MAP routine that is why I try to answer your questions.

[ac427]

MAP sensor is used in normal condition but with a very limited impact on the RF as I said before.

Yes, RF from MAP sensor is also used in case of failure (throttle position for example).

I also disassembled the whole MAP routine that is why I try to answer your question.

Thanks, i didn't mean it to look like i disbelieve you, it was more to add some history to the post.

[MpowerE36]

Thanks, i didn't mean it to look like i disbelieve you, it was more to add some history to the post.

No problem