[Gmecm] Choosing ECM?

Fri Sep 16 22:46:47 UTC 2011

Code 59 is a hacked up version of GM ECU code/firmware.  There is a
group of people working on it at http://www.code59.org  Go check it
out.

The code59 program Uses a 3bar map sensor by default. Thats ~300kPa.
The software originally came form the Buick grand national. Do a
youtube search for that car.  It was a turbo car thats way it had the
300kPa sensor.  If you want to use a 1bar sensor(Im guessing its an NA
engine) you can. I would not put a voltage divider on it.  The ECU
typically does a pretty good job without it.   The problem is with a
loopy cam the changes in pressure are very high between intake valve
open and close at idle.  I think most people fix the problem with
plumbing and not electronics.  Or they ignore MAP at idle.

The code59 program also take all the sensors you are wishing to add
into account for tuning(Intake air temp, coolent temp, TPS and more).
If you want to run LowZ injectors you can change out the injector
drivers in the ECU or you can use a driver board ment for megasquirt.
Lots of people like this one
http://www.jbperf.com/p&h_board/index.html

Also if you have trouble sourcing a US ECM  in europe(I guess your in
europe because you used KPa and not bar) you can check out this site
for info on the euro and aus ECM's.
http://www.delcohacking.net/forums/
They focus on the European and Australian model ECMs  I would just
hunt around on there for one that can run code59 or some similar
software.
The 808 ECM is very popular on that site and may be easy to find
outside the US.  The 7727 and 7730 and its replacements are probably
the most common in Junkyards in the US right now.  GM made a lot of
FWD V6 cars in the 90's.  These can run the code 59 program but they
have high Z injectors drivers. The 7749 which is hard to find, was
used in Turboed cars(buick GN and pontiac turbo sunbird). It has peak
and hold or lowZ injector drivers.

-Avery

On Fri, Sep 16, 2011 at 3:01 PM, Thomas Martin <n0dih1 at gmail.com> wrote:
> He comes off the transbrake now at 6000 rpm and shifts at 8000 rpm.? Alpha N
> is really what he wants, he is planning at the moment, to keep his existing
> distributor and MSD7 in there.
>
> I was thinking if he idles at say 70 kPa and goes to 100 kPa, we could scale
> the MAP with a voltage divider and give him idle at 30 kPa and then he has a
> bit more granularity to run on the VE table.
>
> What is Code 59?? Or is it who?
>
> We are looking at low impedance 90 lb/hr injectors, so I will have to design
> up a high to low impedance driver ckt.? That should be no worries there.
>
> I told him it would be helpful to have a IAT and CTS sensor, but we could do
> without and fix it them too, or put in dash switches for it so he can set
> based on his weather station.? I like the IAT measuring the IAT as it will
> show actual track temps of the air coming in.?? And compensate for cold
> start up.
>
> Tom
>
>
>
> On Fri, Sep 16, 2011 at 4:51 PM, Avery Nisbet <anisbet at gmail.com> wrote:
>>
>> Code 59 has fixed the max RPM limit already. I think its work up to or
>> over 7k now.
>>
>> You could tune for just RPM. ?Because the load will only change when
>> you change tracks or if the weather changes at the track.
>> Replace the Map sensor with a resistor and the TPS will be your only
>> load scaling input. ?There are a lot of EFI systems that work this
>> way.
>> Im sure the GM or mega$quirt stuff can be tricked into do this pretty
>> easily.
>>
>> -Avery
>>
>> On Thu, Sep 15, 2011 at 6:12 AM, David Allen <davida1 at hiwaay.net> wrote:
>> > Thomas,?I would assume that cam does not have a smooth idle and does not
>> > have much vacuum at idle. You may have your work cut out for you tuning
>> > that
>> > thing!
>> >
>> > What level of horsepower and RPM is it running?? Different ECM's and
>> > programs have limitations on the max RPM it can calculate. If you exceed
>> > that RPM it won't output the data correctly and the tables may or may
>> > not be
>> > scalable to that area.
>> >
>> > Not trying to discourage you from this project - just warning of a few
>> > things you will have to overcome.? Others on the list can give more info
>> > on
>> > specifics. I've never run into any RPM limits because my builds have
>> > used
>> > turbos and not high RPM.
>> >
>> > Sincerely,
>> > David
>> >
>> > ----- Original Message -----
>> > From: Thomas Martin
>> > To: gmecm at diy-efi.org
>> > Sent: Wednesday, September 14, 2011 9:48 AM
>> > Subject: [Gmecm] Choosing ECM?
>> > Friend of mine is looking to run his 9.70 at 134-135 mph Olds Small Block
>> > powered race car on EFI. ?Cam is around 324 degrees at the seat.
>> > For those who have run the OBD1 PCM/ECM's, what would be a good choice?
>> > ?He
>> > primarily needs it to handle fueling and timing. ?Or would it really be
>> > better to go with a LS1 PCM like an 0411 and OBD2? ?Not worried about
>> > flashing at the track to make changes.
>> > It needs to idle, and goes WOT. ?It spends very little time anywhere
>> > else.
>> > ?Currently has Nitrous (125 hp shot).
>> > I have RT-CATS Tuner and TunerProRT, Moates APU1 (Burner/real time/RS232
>> > interface/emulator combo) and he has a TPI computer now, he has to look
>> > and
>> > see what PN hardware he has. ?And he has a bunch of PROM's for it.
>> > Thanks!
>> > Tom
>> >
>> >
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