Mass Airflow Sensor

[rbt944]

Hi,
Can anybody clarify me as to why they don't make any hot-wire mass airflow sensor conversions for 84 and older 944's. Have they ever tried to make the conversions? Or are there some out there that I don't know about?
Thanks!!!

[Allldi]

I don't know of any conversions out there. In fact, I've never even heard of conversions for the post '84 944's. If you have, please let me know. Here is my guess as to why none exist. The hot wire sensors measure air mass whereas the mass air flow sensors measure air volume. Air mass is really what the computer needs to "know", so an air temperature sensor goes along with the air flow sensor to correct the air volume measurement into a rough air mass measurement. Designing a conversion would include redesigning the computer to just work from the single hotwire input rather than the two inputs from the mass air flow sensor and from the air temperature sensor. Also, I doubt that if there were any power gains that they would be worth the money. Like I said though, that is just my guess.

[Eduardo Castrejón Elbjorn]

I´m agree with Allldi;

Any 944 have the LH motronic (hotwire, air mass sensor), I don´t know the 968 ?.
The Lh motronic is almost the same as the L motronic, the diference is the use of the air mass sensor in place of the of the air flow sensor (vane plate).
The L motronic is used in the 944s,944s2 (2.7,3.0 16v)and have more features than the motronic (early 944 2.5 8v)
* Knock regulating
* Adaptive circuitry
* Diagnostic circuitry

The vane plate output voltage when open decreases and in the horwire incresases.

Then if you wan to modify your early 944 motronic to use hot wire sensor you will need to replace all your management system. And don´t exist a similar Lh motronic to be used in this engine then will be need to build or modify for this aplication.

If you still want and injection upgrade, bosch,haltech,dinan make racing fuel managements (astronimal costs).

Why Porsche use the vane plate in place of the hot wire ? if the hot wire exist in the beginnin of the 80´s. And is a lot better than the vane plate.
Pobable answers will be:
1.- Bosch sells to Porsche the technology of the fuel managements, then Bosch first obtain money with one system and later offer a better one (money business)
2.- Production costs- Even GM can´t continue to pay the hot wire (84-89 models) system and in 90-96 use a lot cheaper and worst map (manifold absolute pressure )system. until 97 returns to hotwire.

Yes, the hotwire is better than vaneplate but don´t confuse.
Our early 944 motronic was one of most advanced fuel management in his time. If not the best (production)
Also now is a excellent system ! really excellent !
Better than a lot of production fuel management systems like TBI, monotronic,etc.
You don´t need a hotwire, don´t worry with this, be happy with your great system.
Hope this helps
regards

My questions to other members

1.- I only know that Porsche have hotwire in the 928 LH jetronic and Lh motronic, in what other ? 968,993,996 ?

2.- Do somebody know about the new bmw fuel management ystem that don´t have body throttle ?
Use a servomotor to open the intake cam to give to the engine the necesary air ! wow !

[rbt944]

Okay. Thank you both for the info.