Do I need an Air Flow Meter?

[Bruce Plecan]

> >> You mention that I would probably need a sensor for barometric
pressure,
> >> air temp, and RPM.  The stock AirFlow Meter doesn't have any of this.
> > Doesn't have to, it's figuring mass

> Just picking a nit, but the Bosch "flapper-type" airflow meters (as the
> original poster was asking about) do have an air temperature sensor built
> into them, and provide it along with the flapper position.  The later
> "hot-wire" type of airflow meters are themselves temperature sensitive,
> so ambient temperature is accounted for automatically,

It still is calculating MASS, which was the point.
For proper tuning you need an air temp timing correction, IMO..

> To the first poster, if you know airflow correctly, you don't need to
> know engine speed.  Bosch K-Jet doesn't have an engine speed input.
> It does usually have some input related to the throttle position
> (depending on the type, this is either a MAP reference, or a TPS).

He was talkingabout removing it, and then to approximate the air being
consumed you need rpm, if designing a system other then AFM, or MAF

> > Just too hard in my opion to get enough resolution in using just a MAP
to
> > do it. Hard to tell at times if your actually doing what ya seem to be
> > doing because of Baro.
> I would think that MAP would be directly related to barometric pressure,
> since lower barometric would automatically mean lower MAP for otherwise
> identical conditions.  Since you want less fuel at altitude, and you'd
> get a lower MAP value at altitude, a fuel curve matched to MAP, with
> throttle compensation for acceleration, would be adequate.

Try doing it for a while and check back with me.
I would be much easier to develope a single table of 10 items then having to
do one of 100+.
To get the *proper* resolution IMP.

> It's funny how many people are suddenly showing up wanting to replace
> airflow meters with MAP output.  I'd thought about doing exactly the
> same thing to by L-Jet equipped Alfa.

By no means new.
Bruce
>
> james montebello

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org