More silly ideas-MAP2

[Matt S Bower]

Ok the idea should work, the neat setup for this would be what Ludis
said about coding it into the ECM.  I'm in the same boat of that is over
my head to get that done.  If you just compensate the value based on the
second sensor before going to the ecm should still work with some
retuning.  In this case would you have to disable the baro reading at
koeo or wouldn't this be fairly constant.  Either way you would still
want to kill the baro reading at WOT.

Good luck Bruce  (damn airline safety regs always have to cost ya)

Bruce Plecan wrote:
> 
> Yes, there is code for a baro calculation, near WOT.
> But, it isn't a direct reading, which is what I'm after.
> The display on the scan tool is 98 K/Pa, so whatever it's doing is fine for
> gm but not for ultimate performance.   On the 747 is also, a rather crude,
> setup up since it just ignores IAT/MAT.
>   For bracket racing what I have is great, but I ain't bracket racing.
> Bruce
>   CSH, HQ will be closing for a least a few days starting 6/7/99.
> If you think a plane fare is expensive, buy one with O2 for a nasal cannula.
> You can't take your own tank, so you have to buy the O2 from them....
> 
> | Seems to me I've seen code where the MAP is read at WOT for get a new Baro
> | reading. In fact doesn't the 747 have something in there about this?
> |
> | Is this right Mr. Fenske?
> |
> | Terry
> | -----Original Message-----
> | From: Matt S Bower <m.s.bower at cummins.com>
> | To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
> | Date: Friday, June 04, 1999 10:05 AM
> | Subject: Re: More silly ideas-MAP2
> |
> |
> | >
> | >
> | >Jeff M wrote:
> | >>
> | >> Bruce wrote:
> | >>
> | >> >In theory.  when you have Air Densities of 96% to 101% and the
> | >> >scanner shows the engine is at 98 K/Pa under both sets of conditions
> | then
> | >> >there is a fly in the ointment.
> | >>
> | >> MAP gives you pressure and BARO readings (one in the sensed same), and
> | >> density is calculated by adding air temperature computations via a MAT
> | >> sensor (aside from the changes humidity does to the equation, but no RH
> | >> sensors in GM vehicles yet ;-).
> | >>
> | >> To back up a bit, is not Barometric Pressure the measure of air
> pressure
> | >> relative to being at different altitudes and in varying climatic
> | conditions?
> | >> Then when the engine is exposed to these varying outside pressures, it
> | will
> | >> experience different cylinder filling (raw VE tables would not
> compensate
> | >> for this fully) while running.  And since warmer air is less dense (and
> | the
> | >> reverse as well), MAT needs to be added to the equation so (near) true
> | air
> | >> measuring can be performed.  So your fly has definitely landed but I
> | >> wonder if there is a need to compensate for this as it is already done
> on
> | >> better designed cars/computers.  MAP is used to measure barometric
> | readings
> | >> at start up  on many GM vehicles and as an example, the Syclone/Typhoon
> | use
> | >> the MAP to show on my scanner (Diacom Plus) Barometric Pressure,
> Manifold
> | >> Absolute Pressure and Boost Pressure, all supplied via the one MAP
> | sensor.
> | >> Maybe your program (vehicle?) does not do this BARO check and
> associated
> | >> compensation and if so then I would suggest extracting the computation
> | used
> | >> by the Sy/Tys (or others) to be incorporated into your vehicle's
> computer
> | >> program to get you what you want.
> | >
> | >I think you missed the point on this one.  He does have the baro check
> | >but he wants a way for it to continously read baro, not just at start
> | >up.  He wants to make the system more sensative, in a sense, to changes
> | >to be more accurate and try to make it self adjusting to changes is
> | >altitude or the such while he's at it.
> | >
> | >
> | > Another note on GM MAP sensors, they come
> | >> in many ranges depending on application (stay with me here) and not
> just
> | 1
> | >> bar, 2 bar and 3 bar.  GM has found (as it gets it together) that the
> | >> reality of there being more than 1 bar of pressure at altitudes below
> see
> | >> level had a more dramatic effect on some vehicles than others so, GM
> has
> | 1.1
> | >> and 1.2 and 1.25....... "1 bar" MAP sensors.
> | >>
> | >> More FYI:                                            multiply by
> | >> Bars to Atmospheres                           0.9869233
> | >> Bars to Inches Mercury                      29.529983
> | >> Bars to Inches of Water                    401.48716
> | >> Bars to Kilograms per sq centimeter     1.0197162
> | >> Bars to Kilopascals                           100.00 (exact)
> | >> Bars to Psi                                         14.503774
> | >>
> | >> >Weither do to filtering,  the design of the sensor, or pulsation
> | >> characteristics, that the >sensor is reading something is wrong.
> Without
> | >> an emission lab to do the research >something needs done to compensate
> | for
> | >> it.   "My" baro/map idea isn't perfect, but it's a >whole lot better
> | than,
> | >> being in error all the time, IMHO.....
> | >> >Grumpy
> | >>
> | >> You are right about being better, and that is the challenge we all do
> | enjoy.
> | >>
> | >> Jeff Middaugh
> | >> tystorm at email.msn.com
> | >
> |