More silly ideas-MAP2

[Shannen Durphey]

Mike Pitts wrote:
> 
> | I kinda liked the idea of opening the MAP reference to
> | atmosphere so the readings are relative to current BAR.
> | I wonder why this isn't the method that's employed?
> | There must be some sort of problem with it?
> 
> <<$$$,  like everything else gm does money rules..  If they can get close
> with
> a software fix, then that's the way they go.  But, for 3 HP I'll buy a
> second MAP.>>
> 
> If one were to drill a hole in the chamber on the backside,
> opening the MAP up to atmosphere, isn't that the same as
> reading a separate MAP for BAR and doing the subtraction? If so, that seems
> like the cheapest yet still accurate
> way of reading true MAP, since it would already be corrected
> for atmospheric pressure.
> 
> I think I have a spare MAP lying around, I guess I'll
> have to open it up take a look. 8-)
> 
> -Mike
Am I wrong?  Opening the sealed side of a MAP will yeild no (well, an
incorrect) baro reading at key on, engine off.  The sensor is a strain
gauge, and there will be no strain with both sides at equal pressure.
I was thinking of a switch on a timer, and a little info from one of
the gurus.  If the ECM reads BARO after X seconds at WOT, then can we
use a timer set for X seconds after WOT to toggle between MAP sensor
and separate, dedicated BARO sensor?
Shannen