MAP map or MAF map

[Jim Buchanan]

Bryan Zublin:
> I thought that one of the benefits of the MAF was that correction for 
> barometric pressure (altitude) was NOT required.  I do not have practical 
> experience with MAFs, I am merely repeating what I have read in the 
> literature (mainly SAE papers).  Regarding the air temp compensation, isn't 
> this inherent in the MAF because of the reference temp sensor that is 
> upstream of the hot wire?

Are the air-flow sensors that use a flapper and a potentitiometer and the
ones that use a counterbalanced disk in a cone doing essentially the same
thing as a hot-wire MAF?

I've often wondered about this.

If they are, then at least in practice you can get by without measuring the
barometric pressure with a MAF since most of the above-mentioned systems do
not.

AT least two of the above systems _do_ measure temperature, however one
measures engine-block temperature, the other measures cylinder-head
temperature. I assume this is for mixture adjustment as the engine warms
up.


Jim Buchanan        c22jrb at kopt0002.delcoelect.com     jbuchana at holli.com 
=================== http://www.holli.com/~jbuchana =======================
"Some people will tell you that slow is good-and it might be on some
 days-but I am here to tell you fast is better. I've always believed this
 in spite of the trouble it's caused me." -Hunter Thomson
=================== '73 BMW R75/5 "Frau Bluecher" ========================