High Flow MAF revisited - (Porsche 928 voltage MAF)

[Dave Zug]

My interest is to stay with correct system for the year car (89). plus
theres the "because it's there" factor. .. and I beleive when I get to 200
G/S its always on the way to WOT anyway so I don't care if its 258 or 450
just as long as I can tune the unknown area based on RPM.

anyone cruise at 200G/S?

Oh, Did I receive that right... I can flip the Freq bit and use a BUICK MAF?
there ARE large MAFS available for the buick (GN/T etc) from modern
musclecar I think. still cost lot$ and still have to re-cal.


----- Original Message -----
From: Mark Romans <romans at pacbell.net>
To: <gmecm at efi332.eng.ohio-state.edu>
Sent: Sunday, January 16, 2000 9:46 AM
Subject: Re: High Flow MAF revisited - (Porsche 928 voltage MAF)


> Regarding installing a larger MAF sensor. Bruce is right, there is more to
> it than just installing a larger MAF.  The code only recognizes up to 255
> grams/sec.  So even if you get a maf that will read 500 grams/sec the ecm
> won't.  There are probably some people on this list who could write a
patch
> to make the ecm recognize 510 grams/sec but I am not one of them and it
> would take a tremendous amount of time.
>
> Installing a later model gm freq maf is really involved too, the 165 ecm
> using 89 code doesn't recognize freq or over 255 grams/sec so there are
> several issues involved.
>
> I suspect that if one is really serious it would be easier to convert to
730
> ecm or Speed Pro FI with wide band and be done with it.
>
> Mark
> -----Original Message-----
> From: Thomas Matthews <tmatthew at stny.lrun.com>
> To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
> Date: Sunday, January 16, 2000 6:01 AM
> Subject: Re: High Flow MAF revisited - (Porsche 928 voltage MAF)
>
>
> >I figured that it would take a lot of messing around to get it right...
> >But are they similar in their non linear response?
> >Now if someone had the table of 89 MAF voltage to GPS, then could compare
> >the linearity of the two sensors, and fudge the tables in the ECM to
> >compensate for the difference- I would guess that would leave you pretty
> >close.
> >I guess the real answer would be to build a straight F/V converter, and
> flow
> >the 2 sensors to build a response curve of each, CFM /vs voltage, but I
> have
> >no access to a flow bench...
> >SLP used to sell the 3.5 Bosch MAF with a translator, FYI... If anyone
had
> a
> >contact at SLP or one of these translators that they could reverse
> engineer,
> >that would be a quick solution, but then we're still stuck with the Bosch
> >part... but it has been proven to work.
> >I have a totally virgin NIB Bosch MAF, and I'll purchase a LT1 sensor, if
> >the rest of us can come up with time on a flow bench, a translator, and
the
> >voltage to GPS table in the 89 165 code...
> >Any takers?
> >Tom
> >
> >----- Original Message -----
> >From: "Bruce Plecan" <nacelp at bright.net>
> >To: <gmecm at efi332.eng.ohio-state.edu>
> >Sent: Sunday, January 16, 2000 8:27 AM
> >Subject: Re: High Flow MAF revisited - (Porsche 928 voltage MAF)
> >
> >
> >> Either sensor has the common trait, of not being linear.  Look at K
> >Kelly's
> >> chart.
> >> There ain't no way some simple little V/F or F/V or combination there
of
> >is
> >> going to do what you want, acurately.  One other option, rewrite the
> code,
> >> ya right, like that is easy.  Or use a Microprocessor, and do it
right..
> >> If some one who is really good with code had enough info., that would
be
> >> doable (and with a tad more work we could have a MAP to MAF or MAF to
> MAP)
> >> converter.  Now, the last option would be clever, IMHO.
> >>   Grumpy
> >
> >
>
>