Re: BPW and Cylinder Vol.?

[Scot Sealander <Sealand@clarityconnect.com>]

Roger Heflin wrote:
 
> I am still trying to figure out how you guys are tuning this way.

You and me both!


> My thought on tuning was to leave the computer closed loop, and then
> based on how far the computer adjusts the BLM/int's at a given
> point then adjust the VE at that point based on that until things get
> reasonable close.

Here is another step in automating this.  A lot of the P4 ECMs have a 
provision to add a 2kx8 static RAM chip.  At ECM power on, transfer the
VE 
tables from PROM to the added RAM, and then run the engine from the RAM
VE
tables.  Instead of adjusting BLMs, allow the ECM to adjust the VE value 
in RAM in the location where you are operating the engine!

I have done this, and it works just super.  One problem is the pain of
reading the RAM before every shut down, and then adjusting the PROM
data.
Over and over and over.  ;-)

To fix that problem, I found that JDR carries a 2kx8 "Zeropower" SRAM.
They work great in the place of the old static RAM.  They have their own
built-in battery back-up, and remember the VE tables in between
start-ups.  
Now there is no need to read the RAM before every power down.  The ECM
is
constantly learning the VE curves of the engine as you drive!  Neat
stuff.

I only wrote a program to *read* the added RAM, but with a little more 
programming effort, one could easily adjust the VE values in RAM on the 
fly.  Who needs an expensive emulator getting in the way!  This solves a 
number of problems, as it will not have to "steal" CPU cycles the way
an emulator does, and there is not another PC program to bother with
and/or switch between.

For those running a '727 ECM, GM built an ECM with the 2k RAM already
populated.....  Don't remember the number, but '396 comes to mind...
Did use one for a while, worked really well.

Scot Sealander

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