VE and BLM cell edges

[Bob Wooten]

I don't think that I am following completely.  Pardon the ignorance &
indulge me for a minute.  this Util allows me to enter in the BLM value as
I record them (diacom, data master etc) when i am running the car.  the
Util will now say, if you are here (X) & you want to be here (128) then you
need to change the VE table by this (Y).  This makes sense to me & follows
what Dan said two emails ago.  

I think that the other thing you are saying (& here is where i am lost) is
about the Cell edge values.  what I am reading here is that if the X axis
of the line is 600 rpm, then the question is that line from 600 rpm to 699
or is it from 501 to 600?.?.?.?.?  am I following or am i totally out to
lunch?  & I am not following the last paragraph about the KPA @ all (brain
dead).  

also I think that you are saying that you deciphered this information from
the ANHT hac (that i have not gotten to yet). 

If i am tracking right this sounds to me like a huge step towards science &
less of the "This feels like a touch here & a scosh there & a tad over @
this part".  

thanks
BW



> [Original Message]
> From: Dave Zug <dzug at delanet.com>
> To: <gmecm at diy-efi.org>
> Date: 1/17/01 6:00:42 PM
> Subject: VE and BLM cell edges
>
> I have attempted to put BLM based adjustments in perspective with the
layout
> of the lower VE table in the '730 / 727, with the stock BLM cell edge
> settings in mind.
> 
> Here is a link to a snapshot I made of the tuning aide util I have been
> messin with, I expanded it just a minute ago, to include the concept. This
> monster is growing as I enter new areas of actual tuning on my '730 swap.
> Don't ask.. Its outta control... still not ready for beta testers ;-(  It
> now will allow you to enter BLM recorded values and automatically adjust
> your VE lower table. (not upper yet, later). I think if others are doing
> similar packages that this is a useful addition, long as it is splained
good
> enough.
> 
> http://www.delanet.com/~tgp/92Z28/pics/blcells.jpg
> 
> Comments as to my interpretation of the cell edge values, which I am
> confident of since I not only looked at the HAC BL cell map picture that
> everyone has, but I also looked in the assembly code to see if the cells
are
> inclusive or exclusive, in relation to the cell edge values. they are
> exclusive (ie 700 rpm belongs in the HIGHER cell, not the lower one.)
> 
> This is not an original thought, but It seems to illustrate that if one
were
> to change the (Kpa) cell edge settings just a *bit*, that they would
> corrolate more easily to edges in the lower VE table..no?
> 
> 
> 
> ----- Original Message -----
> From: Dan Townsend <xybertron at cox-internet.com>
> To: <gmecm at diy-efi.org>
> Sent: Wednesday, January 17, 2001 10:33 AM
> Subject: Re: Questions from a newbie
> 
> 
> > You take the BLM and divide it by 128.  If it is say 150 then you
multiply
> > the VE by 1.17 so the VE goes up because you are lean and need more
fuel.
> > If the BLM is 100 then you multiply the VE by 0.78125 since you are
> running
> > rich and want less fuel.  Following now?
> >
> > Dan
> >
> > ----- Original Message -----
> > From: "Drew Skinner" <drew.skinner at lcra.org>
> > To: <gmecm at diy-efi.org>
> > Sent: Wednesday, January 17, 2001 8:20 AM
> > Subject: Re: Questions from a newbie
> >
> >
> > > Yeah, that's what got me thinking that I had a vacuum leak. My stock
VE
> > along with the cam netted some 4-5ms pulsewidths at idle, which had me
> > changing fuel soaked plugs every week and not odriving the car for fear
of
> > washing out rings and ther nasty things. After reading Bruce's tuning
tips
> > and prog101, I tried the old take %error in BLM and multiply VE and that
> > made everything much worse (~6-7ms PW) so I went the other way with VE.
> > >
> > > My stock programming at 40-50KPA and 750 or so rpm had the ECM looking
> at
> > VEs in the mid-high 60%, so I cut that back little by little and the
idle
> > PWs have come down to 2.0-2.4ms. I'm kinda at a loss, because this is
> > obviously the opposite of what the ECM seems to want, but the engine is
> much
> > happier. People (tuners) I have talked to with bigger cams and such have
> > mentioned that at low rpm (idle) larger cams with lots of overlap are
less
> > efficient and therefore require less fuel or VE in the table. Looking at
> > Bruce's VE table for the crossfire stuff I'm thinking I'm on the right
> > track, I tried building a table closer to his and the car wouldn't idle.
> So
> > I think I've found the two extremes and just need more iterations to get
> it
> > right. As it is I haven't touched the upper VE table so the car
hesitates
> as
> > it crosses the magical 1600rpm limit into the other VE table and PWs
jump
> up
> > about 1.5ms or so.
> > >
> > > Does this logic sound completely screwy or does it seem like I'm doing
> > alright here?
> > >
> > > Drew (waiting for the king sized CSH)
> > > '89 IROC
> > >
> > > >>> RRauscher at nni.com 01/16 6:51 PM >>>
> > >
> > > Drew,
> > >
> > > You mentioned trying to lean the VE table down, maybe a typo, but high
> > BLMs
> > > would be adding fuel. A 40-45 Kpa idle sounds good, about 16" vac.
With
> a
> > > 224 @ .050 & .465" lift, 108 LDA, runs about 50-55 Kpa in a 327.
> > >
> > > BobR.
> >
> >
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> 
>
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--- Bob Wooten
--- r71chevy at earthlink.net
--- www.r71camaro.homestead.com 


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