My biased opinions

[Greg Hermann]

>Mike Pitts wrote:
>>
>> >>I thought a few of you guys were working on a sequential
>> >>speed density ecm to adapt to the buicks? sequential and
>> >>DIS on a syty...ahh, that would be nice...
>>
>> FelPro already worked on this.  8-)
>>
>
> If you've got 3 grand to plop down.
>
>
>> I don't think sequential is "all-that" unless you are trying
>> to make big injectors idle cleanly.  Or you don't like the
>> hydraulic shock on the fuel rail associated with batch fire.
>> FWIW: My GN runs alot better with a batch fire DFI than it
>> does with the sequential OEM ECM.
>
> Good point. The fuel system is a "fluid" system, and we use
>accumulators on things like that, to control shock. (kinda like the fuel
>pump pulsator everyone, including me, pitches)
>
BUT--<<WATCH IT>> !!  with using an accumulator on a system with a rising
rate regulator--the "capacitance" you add this way will screw up fuel
pressure response rate!!!! An accumulator with a stiff enough spring to
just absorb hammer shocks above your max regulated pressure and a real
small volume would be OK--no real volume storage to it--but with a softer
spring and any significant volume storage, an accumulator CAN screw things
up ROYALLY!! EVEN WITH  fuel pressure regulated at a constant pressure
difference above boost, same concern, cuz the gauge pressure of your fuel
rails will still be changing relative to the accumulator's reference
pressure.

Regards, Greg
>

>> Adding wideband O2 capability to the OEM ECM...now that would
>> be trick in my book!  Adapting a system which uses a large
>
> That'd be cool. Been wanting to do that, too.
>
>> =====================================================
>>
>> |>One thing I have always wanted to do, is to make the
>> |>7148 ecm programmable, kinda like a DFI.
>>
>> I think making the 7148 programmable is a waste of time.
>> That ECM is so outdated it's pathetic.  Plus most of the
>> ROM is permanently embedded (without MAJOR modification).
>>
>
> Hehe.. like usual, I do value your most biased opinion and comments,
>Mike. I think you are one smart cookie, personally. :^)
> The thing I was looking at is the massive changing of the wiring and
>sensors on the TR's, going to a different animal all together. If it
>wasn't such a pain, I would have already been running my car on one.
>
>> This is not a flame, it's just that I've been inside a
>> newer P4 PCM and have "seen the light". Compared to C3's,
>> the P4's rock!  It's like comparing an Apple-II to a
>> Pentium-II.
>
> Kinda looked like that to me, too.  No flame taken. :)
>
>
>> Personaly I am working with an 8625, which is similar to
>> the 7749 but has electronic trans capability as well. I've
>> even located some EEPROM in the MCU which was unused and
>> have already written a code patch to place the VE table in
>> that location and another patch to allow me to alter it
>> from a laptop.  (ala: DFI-like capability)  But like
>> Brian's 3-bar code, it's not ready for prime time yet.
>
> Very interesting! Gonna figure out the data logging side of things? Got
>this figured out for your GN?  Keep me.. er.. us posted!
>
>***********************************************************************
>Dan Smith      84 Regal   12.13 at 112     GSCA# 1459
>St.Charles, Missouri
>mailto:dcsmith at gnttype.org
>http://www.tetranet.net/users/morepoweral
>***********************************************************************