Advice requested for choosing aftermarket EFI system

[Bruce]

From: "Robert" <robert_hiebert at sunshine.net>
> Thanks for your input. I'm not knowledgeable enough to hack a stock ECM,

Some have been already done

>and
> my experience with piggy backing ( EEC Tuner ) has been less than perfect.

Wouldn't that be an indicator of what some of the aftermarket stuff is?.

> As I see it, unless you have absolute and complete knowledge of how the
OEM
> system works and how all the tags interact, there is always a danger that
> there will be a communications failure or some other unforeseen problem.

Any you think some aftermarket firms are more aware of that then the likes
of GM?.   Gonna carry a spare ecm just in case?.  Who do you think the
aftermarkets copy?.

> At
> least with a stand alone aftermarket system, assuming that it is a good
> system, you are in total control.

Key word *assuming*.
The aftermarkets are distilled mins., can be good for a straight out race
car, can be a PITA for a street car.
Bruce

> Regards,
> Robert
> ----- Original Message -----
> From: "Bruce" <nacelp at bright.net>
> To: <diy_efi at diy-efi.org>
> Sent: Thursday, January 03, 2002 4:15 PM
> Subject: Re: Advice requested for choosing aftermarket EFI system
>
>
> >     I'd really appreciate some opinions on experiences any of you may
have
> > had with any of these manufacturers, as well as what features would be
> best
> > suited to my application. These questions, posed to some of the dealers
> were
> > met with unsatisfactory responses, or no response at all. They are as
> > follows.
> > Given the application;
> >
> > 1 - Is there any advantage in multi toothed crank angle sensors or 4
> magnet
> > crank angle sensors as opposed to the stock hall effect distributor pick
> up?
> >
> > For your use no.
> >
> > 2 - Is there any advantage to direct fire, waste spark ( 4 coils )
> ignition
> > as opposed to distributor?
> >
> > Coil near plug is the way to go, IMO.
> > It probably border line sounds crazy, but I think there is alot in
> allowing
> > the coil/coils cooling alot between firing cycles, keeps the primary
> > resistance lower.
> > A long the same lines, DIS is better then single coil.
> > The DIS and CNP eliminate the HV points of failure that a distributor
has.
> >
> > 3 - Is there any advantage to sequential,  "semi-sequential"  (
cylinders
> > paired for ignition with paired injectors),  or batch fired every engine
> > revolution, as opposed to batch fired on alternate engine revolutions?
> >
> > Only SEFI advantage at all is a small amount at idle, or when running
huge
> > injectors at short durations at idle.   99% of the time the injectors
are
> > just spraying fuel at the back of a closed intacke valve.
> >
> > 4 - Is there any advantage in tuning for use with 92 octane fuel as
> opposed
> > to 87?
> >
> > IMO, YES.
> > I did fleet service of tow trucks, cop cars, recovery vehicles, and the
> > higher octane fueled vehicles always lasted longer.   Not 10-30 vehicles
> but
> > rather closer to 100 and millions of miles.
> >
> > 5 - Would it be better to use MAP, or TPS for load sensing?
> >
> > Both.
> > My suggestion is find a hac'd ecm and work off of that.  I carry a spare
> ecm
> > in my car, cost $35.   Kill a aftermarket one, and just wait for UPS or
> Fed
> > Ex to drop off a replacement.  For racing, and rare street use the
> > aftermarkets have their place, for a work horse oem application, my
money
> > would be on a modified stock one
> > Bruce
> >
> > Thanks in advance.
> > Robert


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