Best EFI Choice? (GM, EECIV, Mopar)

[Frederic Breitwieser]

Well, you have several choices.

>From what I can tell, GM systems, particularly late 80's stuff, are much
better documented and of course with most GM stuff, there is a higher level
of cross-compatibility among systems.  For my mopar 383 twin turbo stroker
(431cid) I used the 149 Sy/Ty ECM with a reasonable amount of success,
considering I did not complete the tuning aspect of the system.  I think you
will find the GM OEM stuff easier to work with, because people have spent an
enormous amount of time writing programmers, documenting code, documenting
chipsets, etc.  There is a lot of stuff in the DIYEFI archives that will
benefit you if you dig it out.  I bought a programming tool for 200 bucks
for the 149 ECM which is absolutely out of this word - and while its a DOS
program, it is doing everything I want.  I can give you the exact name and
link when I get home, I do not have my bookmarks handy.  There is also a
java-based programmer for some of the GMECMs which is also a good tool,
however I didn't see the need to load a 50MB java SDK to run a 64k Java
file.  To each their own.

EEC-IV is definately a good system, and appears to be more tolerant of
engine modifications than the GM stuff, as I ran a paxton blower on my V6
Lincoln for many years, and the EEC-IV figured it all out and managed the
engine appropriately.  Even at idle and WOT.  The only drawback to EEC is
that its not as clearly documented as the GM stuff on the web at this point
in time.  Over the next year that shall change, however at least from what I
can tell, its still a little behind the GM stuff.

Chrysler, well, forget it.  I've seen little to nothing for Chryslers, and I
have a complete 318 EFI TBI setup sitting in a box that I have no use for.
It was very frustrating to rip apart and try to reverse engineer, and I
opted to use the GM stuff instead.

Irregardless of which OEM system you utilize, you more than likely will have
to modify either the code or the inputs.  Input modification is how the
piggyback modules work - they interprete the data (analog signals) coming
in, then in turn, pass out different analog signals to the ECM.  By changing
the input to the ECM, these modules can modify system performance.  of
course you can change the code, but the obvious drawback is all the special
tools you need to buy or build.  The Syty programmer software I recommended
above is very good, however it requires programming a PROM, opening the ECM,
inserting said prom, then restarting the car.  not exactly effective for "on
the fly" racing.

An alternative to all these problems, and usuallly takes less time to
install, fabricate, and code, is one of the aftermarket ECMs.  Haltach and
Electromotive offer a variety of solutions that out of the box can have a
"default" engine similar to yours selected, then you build your
configuration form there with any normal serial port on a laptop (or a
desktop if you have a cart and a long cord ::grin::).  Anyway, I've used
both the haltech and the electromotive TEC II systems, and I prefer the
latter.  it has direct ignition much like the modern, newer GM stuff, and is
absolutely stable to 8000 RPM.  They are not cheap, however in one weekend,
you can install such a system, and have a fairly tuned running car in 2
days.  tweak from there.  You can also save cost by using junkyard sensors
rather than buying stuff brand new.

Too many options to really help you select, but hope I presented at least a
basic picture of what is available.

happy searching.