Advice requested for choosing aftermarket EFI system

[Robert]

Hi Bruce,
Thanks for your input. I'm not knowledgeable enough to hack a stock ECM, and
my experience with piggy backing ( EEC Tuner ) has been less than perfect.
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. At
least with a stand alone aftermarket system, assuming that it is a good
system, you are in total control.
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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