Part Throttle tuning for MAF (was MAF tables have a max of 255)

[timsiford at hushmail.com]

Mark,

Right on!

Tim

At Mon, 25 Sep 2000 10:20:27 -0700, romans at starstream.net (Romans, Mark) 
wrote:

>
>Initial fuel*(BLM/128) = adjusted fuel.
>So if the BL is 135 and the maf is reading 50 grams/sec then you need 
>to add
>about 5.5%
>to the grams sec maf calibration for the area of 50 grams/sec. So it 
>would
>be 52.73 grams
>sec instead of 50 grams/sec.  I would also skew the area around the 
>50
>grams/ sec area
>upward a bit too.  If the whole map is reading like this then you can 
>either
>change the injector
>constant or raise or lower the fuel pressure.
>(I think my math is right)
>Mark
>----- Original Message -----
>From: "JN" <jwn at sgi.net>
>To: <gmecm at diy-efi.org>
>Sent: Monday, September 25, 2000 5:11 AM
>Subject: Re: Part Throttle tuning for MAF (was MAF tables have a max 
>of 255)
>
>
>> I may be way off here but I think to do what you want you have to 
>modify
>the
>> MAF tables.  The MAF tables contain values that tell the ECM how much 
>air
>is
>> being ingested in the motor. If the MAF is ported, these figures become
>> skewed.  There is no BPW vs load as you mention that I know of.  The 
>MAF
>> should calculate that on its own.  Again, I'm kinda new at this so 
>I might
>> be way off.
>> Please let me know what you find out since I have an 89 Corvette that 
>I am
>> building a 396 for with a Super Ram.
>> Jason Norris
>> ----- Original Message -----
>> From: <timsiford at hushmail.com>
>> To: <gmecm at diy-efi.org>
>> Sent: Sunday, September 24, 2000 1:03 PM
>> Subject: Part Throttle tuning for MAF (was MAF tables have a max of 
>255)
>>
>>
>> > Hmmmm,
>> >
>> > How come the $32 and $32B code both have a BPW Fuel vs Load (g/sec) 
>and
>> > the $6E does not?  Or, is it just that TunerCat shows the BPW table 
>in
>the
>> > $32 and $32B but not in the $6E?
>> >
>> > The reason that I am asking is this....
>> > With an '89 corvette TPI (heads/cam - 165, $6E), Diacom reports 
>a BLM of
>> > 118 at 1500rpms with a load of 40 g/sec (diacom actually reports 
>4000
>but
>> > I assume they really mean 40?).  This is NOT at WOT.  I'd like to 
>be
>able
>> > to modify the image so that the BLMs are close to 128 almost all 
>of the
>> > time.  If I had a $32 or $32B I would adjust the BPW vs Load (g/sec).
>> However,
>> >  this table doesn't exist in the versions of the $6E calibration 
>file
>that
>> > I have for BOTH TunerCat and the Demo GMEPRO.  Am I missing something
>> here?
>> >  How do you tune part throttle closed loop operation on MAF '89 
>code
>> ($6E)?
>> >  Can anyone shed any light or help out here?  The speed density 
>setups
>are
>> > a cinch.  But, there doesn't seem to be any documentation on the
>internet
>> > or in the diy-efi archives on how to tune PART throttle on the MAF 
>code.
>> >
>> > ANY help is GREATLY appreciated.
>> > Tim
>> >
>> >
>> > At Sun, 24 Sep 2000 10:49:57 -0400, "JN" <jwn at sgi.net> wrote:
>> >
>> > >
>> > >It can't be changed but from what I know it can be fooled.  Use 
>the
>> > >PE vs
>> > >RPM table to add more fuel in the upper RPM's.  The MAF is used 
>mainly
>> > >from
>> > >what I understand in closed loop non PE driving modes.
>> > >
>> > >Jason
>> > >----- Original Message -----
>> > >From: <timsiford at hushmail.com>
>> > >To: <gmecm at diy-efi.org>
>> > >Sent: Saturday, September 23, 2000 8:29 AM
>> > >Subject: MAF tables have a max of 255
>> > >
>> > >
>> > >> Quick question:
>> > >> I know a fair amount about speed density setups (730) and am 
>doing
>> > >my best
>> > >> to learn the MAF setups ($6E / 165).  Why is the maximum MAF 
>value
>> > >= 255
>> > >> and can this be changed?
>> > >>
>> > >> Tim
>> > >
>> > >---------------------------------------------------------------
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>> > >
>>
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